Electrons and holes

Indefinite hiatus

2010-10-29T08:23:00.000+02:00

This blog is put on indefinite hiatus.

SiOnyx Closes $12.5M from Bay Area and Seattle Firms, Goes After Camera Phone Market

2010-10-20T08:16:00.001+02:00

At Xconomy: SiOnyx Closes $12.5M from Bay Area and Seattle Firms, Goes After Camera Phone Market

Gone for two weeks

2010-10-01T17:21:00.002+02:00

The blog will not be updated the coming two weeks due to absence of its owner.

Paper watch: recent imaging papers

2010-10-01T09:02:00.003+02:00

A few recent papers (some of them open access).

First, via Austin's imaging blog, a history of confocal microscopy at Biotechniques.com.

At NanoLetters: "Very Black Infrared Detector from Vertically Aligned Carbon Nanotubes and Electric-Field Poling of Lithium Tantalate". From the abstract:

Vertically aligned multiwall carbon nanotubes were grown by water-assisted chemical vapor deposition on a large-area lithium tantalate pyroelectric detector. The processing parameters are nominally identical to those by which others have achieved the “world’s darkest substance” on a silicon substrate. The pyroelectric detector material, though a good candidate for such a coating, presents additional challenges and outcomes. After coating, a cycle of heating, electric field poling, and cooling was employed to restore the spontaneous polarization perpendicular to the detector electrodes. The detector responsivity is reported along with imaging as well as visible and infrared reflectance measurements of the detector and a silicon witness sample. We find that the detector responsivity is slightly compromised by the heat of processing and the coating properties are substrate dependent. However, it is possible to achieve nearly ideal values of detector reflectance uniformly less than 0.1% from 400 nm to 4 μm and less than 1% from 4 to 14 μm.

And finally, seen at Nature Photonics, an open access paper at the Virtual Journal for Biomedical Optics: "Wavefront image sensor chip". The abstract reads:

We report the implementation of an image sensor chip, termed wavefront image sensor chip (WIS), that can measure both intensity/amplitude and phase front variations of a light wave separately and quantitatively. By monitoring the tightly confined transmitted light spots through a circular aperture grid in a high Fresnel number regime, we can measure both intensity and phase front variations with a high sampling density (11 µm) and high sensitivity (the sensitivity of normalized phase gradient measurement is 0.1 mrad under the typical working condition). By using WIS in a standard microscope, we can collect both bright-field (transmitted light intensity) and normalized phase gradient images. Our experiments further demonstrate that the normalized phase gradient images of polystyrene microspheres, unstained and stained starfish embryos, and strongly birefringent potato starch granules are improved versions of their corresponding differential interference contrast (DIC) microscope images in that they are artifact-free and quantitative. Besides phase microscopy, WIS can benefit machine recognition, object ranging, and texture assessment for a variety of applications.

Paper watch: Metal-Insulator-Semiconductor Photodetectors

2010-09-29T08:21:00.002+02:00

A recent paper at the open access Sensors Journal: "Metal-Insulator-Semiconductor Photodetectors". The abstract reads:

The major radiation of the Sun can be roughly divided into three regions: ultraviolet, visible, and infrared light. Detection in these three regions is important to human beings. The metal-insulator-semiconductor photodetector, with a simpler process than the pn-junction photodetector and a lower dark current than the MSM photodetector, has been developed for light detection in these three regions. Ideal UV photodetectors with high UV-to-visible rejection ratio could be demonstrated with III-V metal-insulator-semiconductor UV photodetectors. The visible-light detection and near-infrared optical communications have been implemented with Si and Ge metal-insulator-semiconductor photodetectors. For mid- and long-wavelength infrared detection, metal-insulator-semiconductor SiGe/Si quantum dot infrared photodetectors have been developed, and the detection spectrum covers atmospheric transmission windows.

Paper watch: Custom transistor layout for RTS noise reduction in image sensors

2010-09-28T08:53:00.003+02:00

I will make an effort to overlook the issues from the previous post and point to this nice paper at Electronics Letters describing a custom transistor layout for RTS noise reduction in image sensors: "Custom transistor layout design techniques for random telegraph signal noise reduction in CMOS image sensors". The abstract reads:

Interface and near oxide traps in small gate area MOS transistors (gate area ≪1 μm²) lead to RTS noise which implies the emergence of noisy pixels in CMOS image sensors. To reduce this noise, two simple and efficient layout techniques of custom transistors have been imagined. These techniques have been successfully implemented in an image sensor test chip fabricated in a 0.35 μm CMOS image sensor process. Experimental results demonstrate a significant reduction of the noisy pixels for the two different techniques.

I like that the techniques have been "imagined" but also measured: Inception paper? :-)

One possible problem I see is that their transistors are done in a technology with LOCOS. Advanced technologies use STI, so I don't know how well the techniques translate to e.g. the latest CIS technologies by tsmc and others.

Is anybody editing the papers for Electronics Letters?

2010-09-28T08:41:00.005+02:00

Checking the weekly update of IEEXplore I see the following title for a paper in Electronics Letters: "nth-order multi-bit ΣΔ ADC using SAR quantiser". Being something I'm interested in, I follow the link to check what I think is a sigma-delta with a successive-approximation ADC as quantizer. To my excitement I read the following abstract: "An nth-order multi-bit delta-sigma (ΣΔ) analogue-to-digital converter (ADC) using a synthetic aperture radar (SAR) quantiser is proposed. By exploiting the residue voltage of a multi-bit SAR ADC, the proposed ADC performs as an nth-order noise shaping converter with only one opamp and removes the need for a feedback multi-bit DAC. In addition, the proposed architecture is very reconfigurable and can be implemented as a bandpass ADC.". Wow! That looks pretty cool, how do they manage to put a radar as quantizer and why don't they send it to ISSCC? :-D

Of course, thinking it's a typo that will not appear in the paper itself, I click and lo and behold, the same mistake is repeated in the abstract in the paper. Of course, checking the paper it's obvious it's a successive-approximation register quantizer.

Conclusion? Electronics Letters HUGE FAIL!

Commercial plenoptic cameras

2010-09-24T10:33:00.003+02:00

This escaped me: "The first plenoptic camera on the market".

The technology by Adobe in the video was presented in this paper of the IEEE Computational Photography mentioned in the previous post: "Rich image capture with plenoptic cameras". The abstract reads:

The plenoptic function was originally defined as a record of both the 3D structure of the lightfield and of its dependence on parameters such as wavelength, polarization, etc. Still, most work on these ideas has emphasized the 3D aspect of lightfield capture and manipulation, with less attention paid to other parameters. In this paper, we leverage the high resolution and flexible sampling trade-offs of the focused plenoptic camera to perform high-resolution capture of the rich “non 3D” structure of the plenoptic function. Two different techniques are presented and analyzed, using extended dynamic range photography as a particular example. The first technique simultaneously captures multiple exposures with a microlens array that has an interleaved set of different filters. The second technique places multiple filters at the main lens aperture. Experimental results validate our approach, producing 1.3Mpixel HDR images with a single capture.

High resolution large format cameras

2010-09-24T08:13:00.004+02:00

Hasselblad just announced today that they have developed a 200 Megapixel capture device (found via OISblog).

Coincidentally, yesterday the proceedings of the 2010 IEEE International Conference on Computational Photography were put on line at IEEEXplore, and among the papers there was this one by Moshe Ben-Ezra from Microsoft Research Asia: "High resolution large format tile-scan camera: Design, calibration, and extended depth of field". The abstract reads:

Emerging applications in virtual museums, cultural heritage, and digital art preservation require very high quality and high resolution imaging of objects with fine structure, shape, and texture. To this end we propose to use large format digital photography. We analyze and resolve some of the unique challenges that are presented by digital large format photography, in particular sensor-lens mismatch and extended depth of field. Based on our analysis we have designed and built a digital tile-scan large format camera capable of acquiring high quality and high resolution images of static scenes. We also developed calibration techniques that are specific to our camera as well as a novel and simple algorithm for focal stack processing of very large images with significant magnification variations.

Radiation testing of ICs with Ion-photon-emission microscopy

2010-09-15T08:17:00.001+02:00

A news item at SPIE regarding a new instrument at Sandia National Labs: "Radiation testing and imaging of micro-electronics"

[...] as technology advances, features in satellites and spacecraft are getting smaller and, therefore, more susceptible to radiation damage. IPEM, once fully developed and validated as a means of testing the radiation hardness of micro-electronics, will contribute to the development of new and emerging radiation-tolerant IC technologies far into the future.

Engineering history

2010-09-14T08:30:00.003+02:00

Most of us with access to it use IEEEXplore to check the latest issues of the IEEE journals. But they've also been busy uploading old issues of journals. This week, for example, they've uploaded several volumes from the late XIX century of the Transactions of the American Institute of Electrical Engineers. It is particularly interesting to see, after each paper, a written critical discussion of the contents of the paper by other experts. Why not bring this back?

Worth taking a look, if you have access.

Fuijitu's high speed ADC revisited

2010-09-14T08:22:00.003+02:00

Remember their 56GS/s ADC? Fujitsu has announced their new version, fabricated in a 40nm CMOS technology. Here's their page with info. Here are some slides about this new version.

New IEEE publication on affective computing

2010-09-09T08:39:00.002+02:00

No it's not a typo, it's affective with an "a". The IEEE Transactions on Affective Computing start with a very nice introductory paper by Rosalind W. Picard:

I did not want to work on or be associated with emotion, yet emotion was starting to look vital for solving the hard engineering problems we needed to solve. A scientist has to find what is true, not just do what is popular. I was becoming quietly convinced that engineering dreams to build intelligent machines would never succeed without incorporating insights about emotion. I knew somebody had to educate people about the evidence I was collecting and act on it. But I did not want to risk my reputation and I was too busy. I started looking around, trying to find somebody, ideally male and established, whom I could convince to develop this topic, which clearly needed more attention than I had time for.

Samsung's BSI image sensors for consumer applications

2010-09-07T11:34:00.003+02:00

Samsung reports their first BSI image sensors for consumer applications: press release.

Samsung's new BSI imagers show 30 percent enhancement in low light sensitivity over conventional front side illumination imagers of the same pixel size. By optimizing process parameters, Samsung was able to efficiently control crosstalk thereby improving the color, electrical and optical performance significantly.

The S5K4E5, a quarter-inch optical format 1.4 micron 5 megapixel (Mp) CMOS image sensor, is designed to support full resolution real-time video. By providing 30 frames per second (fps) full resolution frame rates it also enables the user to 'catch the shot' by capturing the frame as the user hits the shutter button thus reducing shot to shot lag time. The 5Mp imager has a wider chief ray angle that reduces the height of the imager package making it attractive for slim, small form factor smartphones with demanding z-height requirements.

The S5K2N1, a 1/2.33 inch optical format 1.4 micron 14.6Mp imager, offers 30fps capability at full resolution and leverages Samsung's low-power 90 nanometer logic process technology. Samsung is able to offer a dedicated thermal enhanced plastic lead ceramic carrier (TePLCC) package to more effectively dissipate the heat generated by the high performance device.

These imagers also offer the ability to capture full high definition (HD) resolution video images at 60fps.

Samples of the 5Mp S5K4E5 are available now with mass production starting in the fourth quarter of this year. The 14.6Mp S5K2N1 is expected to start sampling in the fourth quarter of 2010 with production scheduled in the first quarter of 2011.

EETimes: Researchers develop image sensor for rough environments

2010-09-07T11:28:00.002+02:00

There's nothing yet at the IMS website yet, but EETimes Europe reports on a design by Fraunhofer IMS of an image sensor able to work in an extended temperature range of -40 to 115 degrees Celsius.

Other uses for microlenses

2010-09-07T09:00:00.002+02:00

Although microlenses are mostly used at the "receiving end", in front of image sensors, they are also used (and useful) at the "transmitting end", in front of illuminators. This article at Photonics Spectra, from RPC Photonics, gives an introduction to this application for microlenses.

Paper watch: Machine hearing

2010-09-06T08:24:00.002+02:00

The latest issue of the IEEE Signal Processing Magazine, besides a series of interesting articles on algorithms for security video applications, includes also a good article from a research scientist at Google on machine hearing. The abstract reads:

If we had machines that could hear as humans do, we would expect them to be able to easily distinguish speech from music and background noises, to pull out the speech and music parts for special treatment, to know what direction sounds are coming from, to learn which noises are typical and which are noteworthy. Hearing machines should be able to organize what they hear; learn names for recognizable objects, actions, events, places, musical styles, instruments, and speakers; and retrieve sounds by reference to those names. These machines should be able to listen and react in real time, to take appropriate action on hearing noteworthy events, to participate in ongoing activities, whether in factories, in musical performances, or in phone conversations.

Lenses and cameras

2010-09-06T07:53:00.003+02:00

A somewhat old article which I missed, found at the OISBlog, on electrically tunable lenses.

As the predominant method of focusing images for over a century, mechanical lens motion sharply contradicts the biological methods found in nature. By leveraging principles based on these methods, manufacturers are now developing different types of small deformable lenses that can be tuned over various focal distances. Because these lens systems can be miniaturized relatively easily, they are finding applications in smart machine-vision cameras, endoscopy systems, and cell phones.

And a review of the Canon Expo 2010, with references to both their full wafer, 600 micron pixel and their 120Mpixel detectors. Cool stuff.

Paper watch: Graphene photonics and optoelectronics

2010-09-02T08:34:00.003+02:00

From Nature Photonics, a nice overview of the applications of graphene in the field of photonics: "Graphene photonics and optoelectronics": The abstract reads:

The richness of optical and electronic properties of graphene attracts enormous interest. Graphene has high mobility and optical transparency, in addition to flexibility, robustness and environmental stability. So far, the main focus has been on fundamental physics and electronic devices. However, we believe its true potential lies in photonics and optoelectronics, where the combination of its unique optical and electronic properties can be fully exploited, even in the absence of a bandgap, and the linear dispersion of the Dirac electrons enables ultrawideband tunability. The rise of graphene in photonics and optoelectronics is shown by several recent results, ranging from solar cells and light-emitting devices to touch screens, photodetectors and ultrafast lasers. Here we review the state-of-the-art in this emerging field.

Paper watch: Surface plasmon enhanced responsivity in a waveguided germanium metal-semiconductor-metal photodetector

2010-09-02T08:08:00.004+02:00

A paper at Applied Physics Letters which shows again possible advantages of plasmonics for photodetection. In this case for optical communications: "Surface plasmon enhanced responsivity in a waveguided germanium metal-semiconductor-metal photodetector". The abstract reads:

The authors report on high transverse magnetic (TM)-mode responsivity in a waveguided germanium Schottky-barrier metal-semiconductor-metal photodetector on silicon-on-insulator substrate for operating wavelength at 1550 nm. The employed aluminum interdigitated electrodes act as a one-dimensional rectangular grating above the depletion layer. By means of properly designed finger dimensions, surface plasmon polariton resonances can be excited at the interface of metal and silicon interfacial layer due to grating coupling. The resulting strong field intensities reach into active region, enabling high absorption under TM injection. At a voltage of 1 V, the TM-mode photocurrent is measured over three times than that of transverse electric mode, in spite of the relatively larger TM insertion loss in the silicon waveguide.

Miscellaneous entry: transmission lines, book excerpts, ...

2010-09-01T13:05:00.003+02:00

Unfortunately not much time is left to prepare better entries, so I'm putting together here several topics in one blog entry.

Beginning with a short (but very informative) note from Mentor Graphics on the effects of bends in transmission lines for SerDes circuits.

Continuing with a series on Zigbee applications from EETimes, extracted from a book. parts one, two, three, four, five, six and seven (so far).

Another series from EETimes, extracted from a book on oscillators.

And yet another series extracted from a book on antennas.

Omnivision Q1F2011 earnings call

2010-08-27T10:03:00.003+02:00

Via seeking alpha. some choice quotes:

[...]
First, let me share with you our commitment with BSI technologies development. Our commitment to the advancement of BSI technologies is second to none. As the first company to commercialize the use of this technology, our first generation OmniBSI pixel is already in mass production and has begun to ramp significantly in fiscal 2011 and serves as the basic for our entire 5-megapixel product line.

With the advancement of BSI-2, the second generation OmniBSI pixel, we have further expanded our leadership in pixel technology well ahead of our competitors. The second generation BSI architecture represents a major milestone in digital imaging technology in an aggressive form factor. Meanwhile, most significantly, these technologies serve the basic for meeting the trend towards ever higher pixel counts and establish a trend towards high quality pixel.

Another notable commitment enduring in core sensing technology is our CameraCube technology development. In particular, we remain focused on the development of advanced wafer level optics and packaging solutions for our next generation products and reduce product costs. To this end, we are consistently examining our options and look for solutions to achieve our goal.

Last, but not least, through fiscal 2010, our OmniPixel3-HS technologies continued to gain traction with broad market acceptance due to its leading low light sensitivity. Our latest high performance VGA sensor that is built with our popular 3.0 micron OmniPixel3-HS high sensitivity pixel is well accepted in automotive and the security markets, which also demand high definition color applications.
[...]
Currently, a major trend and expectation in imaging is the increasingly rapid marketplace adoption of high sensitivity, high definition images and video.
[...]
Our BSI products are proven to be a key differentiator that has enabled OmniVision to secure a range of high value customers and projects. We expect that our proprietary BSI technology will continue to be a decisive factor in securing further design wins during the next several quarters resulting in an increasingly prominent position within our vertical target markets.
[...]
In regards to technology of BSI, obviously to ship the quantities that we are shipping today, it’s a long learning curve. We regard that as extremely a big advantage to OmniVision, and our competitors will probably face that step when they get to it. And it’s not easy to ship the volumes we have.
[...]
We have been developing the backside illumination technology with our strategic partner TSMC for many years. This has been a five-year effort for us. And there has been a tremendous amount of intellectual property developed between the two companies in that process. And that’s very hard to reproduce and is very hard to reproduce in a short time period. So if you look at our success and the growth we’ve seen, it’s really been fueled by BSI. So that should give you an indication that a great portion of that learning has already taken place for us. So we think that as a big barrier for the competition.

Pixel ADC MSc Thesis online

2010-08-26T08:19:00.003+02:00

Oops, Image Sensors World beat me to the scoop, and I've been the daily supervisor at imec :-)

Cheng Ma's MSc thesis is available: "Pixel ADC Design for Hybrid CMOS Image Sensor". Good luck in your new job in Antwerp!

Paper watch: Image sensor papers at the IEEE TED

2010-08-20T08:17:00.004+02:00

The latest issue of IEEE Transactions on Electron Devices carries three (at first sight) interesting papers.

The first one is "eLeNA: A Parametric CMOS Active-Pixel Sensor for the Evaluation of Reset Noise Reduction Architectures". The abstract reads:

We present a novel complementary metal–oxide–semiconductor (CMOS) active-pixel sensor imager that incorporates different reset schemes to achieve lower reset noise levels. The sensor, eLeNA, features a 448 $times$ 512 array with a pixel pitch of 15 $muhbox{m}$, fabricated using a 0.18- $muhbox{m}$ CMOS process. Fourteen sections and five different reset methods were employed. Without using pinned diodes, we implanted structures for correlated double sampling. A noise of 6 $hbox{e}-$ is measured with a conversion gain of 49 $muhbox{V/e}-$. We will discuss various applications for the reset method that achieved the best overall performance, considering leakage current and read noise.

The second one is: "Simulation and Measurements of Stray Minority Carrier Protection Structures in CMOS Image Sensors". The abstract reads:

Recently, the rapid growth of CMOS technology has made it possible to integrate more periphery circuits into a CMOS image sensor. Although these periphery circuits improve image quality, they also lead to the generation of more stray minority carriers. Because the number of stray minority carriers is proportional to the frequency, the affected region increases with increasing operating frequency. Placing an appropriate absorber between the periphery circuits and the pixel has traditionally been accepted as the best solution for this issue. Four protection tactics were simulated in software and verified in a fabricated CMOS image sensor. The imager was fabricated using TSMC 1-poly 6-metal 0.18-$muhbox{m}$ process technology. On this chip, ten noise sources outside the pixel array were used to verify the effectiveness of the protection tactics in off-array tests, whereas in-pixel noise sources were used in in-pixel tests. To quantify the influence of stray minority carriers in the off-array test, the maximum depth of an affected region (DAR) was measured in a processed binary image. The off-array experimental results revealed that the DAR increased with either an increased operating frequency or a decreased separation between the noise source and the pixel array. The DAR of the affected pixels can be eliminated up to 48.1% and 23.8% by using the N-well and N-diffusion guard rings, respectively. The in-pixel experimental results have shown that the N-diffusion digital pixel implementation reduced the noise by 63.2% while only increasing the area by 10.68%. Detailed information about the effectiveness of different protection tactics in an imager design was collected in this paper. This paper can potentially provide a reference to help imager designers choose an appropriate protection tactic.

And the third one: "Per-Pixel Dark Current Spectroscopy Measurement and Analysis in CMOS Image Sensors". The abstract reads:

A per-pixel dark current spectroscopy measurement and analysis technique for identifying deep-level traps in CMOS imagers is presented. The short integration time transfer gate subtraction experimental technique used to obtain accurate results is described and discussed. The activation energies obtained for molybdenum (≈0.3 eV), tungsten (≈0.37 eV), and the phosphorus-vacancy (E-center) (≈0.44 eV) trap levels in silicon match published results measured with other techniques. The Meyer–Neldel Relationship (MNR) was observed between the Arrhenius preexponential frequency factor and activation energy. The trap capture cross-sectional calculation methodology using the MNR is presented. The cross sections of molybdenum, tungsten, and the E-center were calculated as ≈1 × 10−16 cm2,
≈1.5 × 10−16 cm2, and≈2.5 × 10−16 cm2, respectively, at 318 K. The data obtained suggest electric field enhanced emission, and Poole-Frenkel barrier force lowering of E-center defects occurs in the pinning implant regions. It is proposed that a changing Fermi level results in the correct activation energies being obtained below half the band gap and that the dark current measurement process is affected by the measurement time result of statistical mechanics. It is also tentatively suggested that, in this case, the observed MNR is a geometric relationship and not due to a physical process.

In case the abstract is a bit confusing, the authors conclude that: "The measurement and analysis technique presented could be useful to the image sensor industry for diagnosing fabrication plant contamination. It also has potential applications for the study of radiation induced traps in CMOS and CCD imagers."

Paper watch: Another step towards usable organic photodiodes

2010-08-19T08:21:00.002+02:00

New paper at Applied Physics Letters: "Organic heterojunction photodiodes exhibiting low voltage, imaging-speed photocurrent gain". The abstract reads:

We report the demonstration of fast and strong photocurrent gain in organic photodiodes with tailored charge blocking layers. The hole blocking layer between the anode and the photoactive layer leads to accumulation of photogenerated holes at its interface with the active layer, which causes a strong secondary electron injection from the anode and as such a high photocurrent gain. Using a bulk heterojunction of C₆₀ and copper phthalocyanine as the active layer, we have achieved photocurrent gains up to 500 across the visible spectrum and bandwidths on the order of 1 kHz, well above the imaging-compatible bandwidth (>60 Hz).

TOF camera projects in Europe

2010-08-19T08:12:00.003+02:00

An FP6 project for short range 3D imaging: ARTTS. Article at CORDIS.

An FP7 project for SPAD-based 3D imaging: MISPIA (could not find a project website).

Paper watch: Latest IEEEXplore update

2010-08-17T08:59:00.004+02:00

Plenty of noteworthy papers in today's IEEEXplore .These are some which will be on my to-read list, based on the abstracts.

First, from TCAS-II:"Event-Driven Data Acquisition and Digital Signal Processing—A Tutorial" from Yannis Tsividis. The abstract reads:

"Event-driven analog-to-digital conversion and associated digital signal processing techniques are reviewed. Such techniques, still in the research stage, have the potential to significantly reduce the consumption of energy and bandwidth resources in several important applications."

From IEEE's Transactions on Image Processing, a paper from Sony's Image Sensing Technology Department: "Generalized Assorted Pixel Camera: Postcapture Control of Resolution, Dynamic Range, and Spectrum". The abstract reads:

We propose the concept of a generalized assorted pixel (GAP) camera, which enables the user to capture a single image of a scene and, after the fact, control the tradeoff between spatial resolution, dynamic range and spectral detail. The GAP camera uses a complex array (or mosaic) of color filters. A major problem with using such an array is that the captured image is severely under-sampled for at least some of the filter types. This leads to reconstructed images with strong aliasing. We make four contributions in this paper: 1) we present a comprehensive optimization method to arrive at the spatial and spectral layout of the color filter array of a GAP camera. 2) We develop a novel algorithm for reconstructing the under-sampled channels of the image while minimizing aliasing artifacts. 3) We demonstrate how the user can capture a single image and then control the tradeoff of spatial resolution to generate a variety of images, including monochrome, high dynamic range (HDR) monochrome, RGB, HDR RGB, and multispectral images. 4) Finally, the performance of our GAP camera has been verified using extensive simulations that use multispectral images of real world scenes. A large database of these multispectral images has been made available at http://www1.cs.columbia.edu/CAVE/projects/gap_camera/ for use by the research community.

The latest Transactions on Nuclear Science serves as proceedings from the RADECS 2009 conference. Some choice papers:

"Current and Future Challenges in Radiation Effects on CMOS Electronics" from Sandia Labs
"Failure Modes and Hardness Assurance for Linear Integrated Circuits in Space Applications" from CIT's Jet Propulsion Lab.
"A Commercial 65 nm CMOS Technology for Space Applications: Heavy Ion, Proton and Gamma Test Results and Modeling" from ST.

From the conventional TNS issue:

A "copernican shift" in science?

2010-08-14T13:40:00.003+02:00

First it was discovering the LiquidPub project:

The LiquidPub project proposes a paradigm shift in the way scientific knowledge is created, disseminated, evaluated and maintained. This shift is enabled by the notion of Liquid Publications, which are evolutionary, collaborative, and composable scientific contributions. Many Liquid Publication concepts are based on a parallel between scientific knowledge artifacts and software artifacts, and hence on lessons learned in (agile, collaborative, open source) software development, as well as on lessons learned from Web 2.0 in terms of collaborative evaluation of knowledge artifacts.

And then I read this article about how sharing scientific data has led to advances in the fight against Alzheimer's.

At first, the collaboration struck many scientists as worrisome — they would be giving up ownership of data, and anyone could use it, publish papers, maybe even misinterpret it and publish information that was wrong.
But Alzheimer’s researchers and drug companies realized they had little choice.

Paper watch: A cheap portable fluorescence microscope

2010-08-05T10:03:00.002+02:00

Via Nanowerk, a new paper at PLoS: "Portable, Battery-Operated, Low-Cost, Bright Field and Fluorescence Microscope". The abstract reads:

This study describes the design and evaluation of a portable bright-field and fluorescence microscope that can be manufactured for $240 USD. The microscope uses a battery-operated LED-based flashlight as the light source and achieves a resolution of 0.8 µm at 1000× magnification in fluorescence mode. We tested the diagnostic capability of this new instrument to identify infections caused by the human pathogen, Mycobacterium tuberculosis. Sixty-four direct, decontaminated, and serially diluted smears were prepared from sputa obtained from 19 patients suspected to have M. tuberculosis infection. Slides were stained with auramine orange and evaluated as being positive or negative for M. tuberculosis with both the new portable fluorescence microscope and a laboratory grade fluorescence microscope. Concordant results were obtained in 98.4% of cases. This highly portable, low cost, fluorescence microscope may be a useful diagnostic tool to expand the availability of M. tuberculosis testing at the point-of-care in low resource settings.

Nice to see also that is the result of a USA-Iran collaboration.

A couple of items from TSMC's Q2 earnings call

2010-07-31T13:24:00.003+02:00

From seeking alpha.

[...]
For CMOS image sensors, we use 65-nanometer and backside illumination to achieve the best quantum efficiency.
[...]
For MEMS, we use 0.18-micron to compete 3D CMOS MEMS integration.
[...]
We have also experienced, accelerated our sourcing by IBMs and growing presence of fabless customers in specialty technologies, such as CMOS image sensors, embedded memories, high voltage, automotive and power.
[...]
Through the recent technology license and the investment agreement with Stion Corporation, we are transferring and developing together high conversion efficiency CIGS thin-film technology with a very low intrinsic cost structure, based on which both companies will aggressively build our manufacturing capacity to scale in the near future.
We strongly believe that CIGS technology will provide a long-term competitive solution to this high growth market. Earlier, strategic investment in Motech, which is a major crystalline silicon solar photovoltaic manufacturer has accelerated our learning curve and their solar cell support will enable our early entry in the solar market.

Paper watch: Nature Photonics

2010-07-30T08:03:00.003+02:00

The latest issue of Nature Photonics is out and focuses on silicon photonics. Choice articles:

Towards fabless silicon photonics.
An interview with Intel's Mario Paniccia on integrating silicon photonics.
Monolithically integrated solid-state Terhahertz transceivers. Abstract:
"Recent advances in microfabricated terahertz quantum cascade lasers have achieved coherent power and frequency performance previously possible only with much larger gas- or vacuum-tube sources. A significant advantage offered by terahertz quantum cascade lasers lies in the potential to integrate them with other components on the same chip. Such terahertz photonic integrated circuits would help close the terahertz technology gap between microwave electronics and infrared photonics. Here, we describe the first successful monolithic integration of a terahertz quantum cascade laser and diode mixer to form a simple but generically useful terahertz photonic integrated circuit—a microelectronic terahertz transceiver. We show that this terahertz photonic integrated circuit performs all the basic functions (for example, transmission of a coherent carrier, heterodyne reception of an external signal, frequency locking and tuning) of discrete-component terahertz photonic systems, but at a small fraction of the size and in a robust platform scalable to semiconductor fabrication production."
High-performance Ge-on-Si photodetectors. Abstract:
"The past decade has seen rapid progress in research into high-performance Ge-on-Si photodetectors. Owing to their excellent optoelectronic properties, which include high responsivity from visible to near-infrared wavelengths, high bandwidths and compatibility with silicon complementary metal–oxide–semiconductor circuits, these devices can be monolithically integrated with silicon-based read-out circuits for applications such as high-performance photonic data links and infrared imaging at low cost and low power consumption. This Review summarizes the major developments in Ge-on-Si photodetectors, including epitaxial growth and strain engineering, free-space and waveguide-integrated devices, as well as recent progress in Ge-on-Si avalanche photodetectors."

Frankencamera demo

2010-07-30T08:00:00.002+02:00

At Technology Review, a nice video showing the capabilities of the Frankencamera, and its accompanying article.

More X-ray sources for lower dose in CT

2010-07-29T16:56:00.003+02:00

A nice article at IEEE Spectrum about the developments in GE for more efficient CT scanners (dose-wise): Many X-rays Are Better Than One.

The article refers to this talk at the AAPM meeting, which includes some references to SPIE papers in the pdf abstract to the talk.

Wireless power standard announced

2010-07-29T14:03:00.002+02:00

From EDN's Power Source blog, an announcement of a standard for wireless power. How they claim to compensate for the low efficiency of this type of power delivery still raises some questions, but at least they try to address the issue.

Let's also hope that they update their blog more often. But their website offers a lot of technical information, and it's well designed.

Electrons and Holes @ Twitter

2010-07-29T11:43:00.003+02:00

You can now follow this blog at Twitter for shorter/(hopefully more often) updates and links. BTW, you don't need a twitter account, you can subscribe to the rss feed.

Paper watch: EDA and social networks?

2010-07-28T09:01:00.003+02:00

Another conference with its proceedings online at IEEE Xplore is DAC 2010 (free table of contents). It might take a while but they usually put the proceedings online for free at their website.

I found this paper from the conference a bit odd: Electronic Design Automation for Social Networks

Online social networks are a growing internet phenomenon: they connect millions of individuals through sharing of common interests, political and religious views, careers, etc. Social networking websites are observing an ever-increasing number of regular users, who rely on this virtual medium to connect with friends and share in the community. As a result, they have become the repository of a vast amount of demographic information, which could deliver valuable insights to businesses and individuals. However, as of today, this data is for the most part still untapped, partly because of the complexity entailed by analyzing some of these vast social connectivity graphs. Another area that deals with large data sets is Electronic Design Automation (EDA), the result of increasingly complex computer systems. The powerful tools used to deal with these data sets open many possibilities for social networks. In this work we propose to study interesting aspects of social networks by deploying some of the solutions commonly used in EDA.

CSI's IEEE conference

2010-07-28T08:38:00.002+02:00

Just found in today's IEEXplore update the proceedings for the 2009 International Conference on Crime Detection and Prevention. The programme can be freely accessed here.

Phil Garrou is back online

2010-07-28T08:11:00.004+02:00

After the closing down of Semiconductor International I really missed Dr Garrou's insights in the 3D packaging world. Well, he's back online at ElectroIQ: Insights from the leading edge. Add it to your bookmarks!

He also put all his old blog posts from his time at Semiconductor International at this place.

Paper watch

2010-07-26T08:25:00.005+02:00

From the latest IEEXplore update, some interesting papers I found.

First, at the IEEE Electron Devices Letters, NXP engineers working on noise modeling report on excess noise for small channel devices:

Accurate modeling of thermal noise in MOSFETs is crucial for RF application of deep-submicrometer CMOS technologies. Here, we present RF noise measurements on four commercial advanced CMOS technologies down to the 45-nm node. Based on this extensive set of measurements, we prove the existence of excess noise (i.e., above the pure Nyquist level), but at the same time, we show that it is significant only for sub-100-nm MOSFETs. The amount of excess noise depends mainly on the channel length, and its occurrence is remarkably universal across technologies. We also present an electric-field-dependent extension of Nyquist's law that represents a nonequilibrium-transport correction to diffusive transport. We show that this microscopic model quantitatively explains the main features of the experimentally observed excess noise for all technologies. This includes its bias dependence, its geometrical scaling behavior, and the observed difference between n-channel and p-channel devices.

Next, three interesting papers at the Journal of Solid State Circuits, which changes editor-in-chief from Bram Nauta to Un-Ku Moon.

The first one is about "continuous-time" pipelined ADCs, where the continuous time refers to the first stage not being switched-capacitor. Interesting concept, although the FOM is not that impressive. And it still bothers me that one can quote 11 bit resolution with 56 dB SNDR. Additionally, they write in a figure that the ENOB is "9.09 dB".

More interesting is the one by Razavi on Cognitive Radio Design Challenges and Techniques:

Cognitive radios are expected to communicate across two or three frequency decades by continually sensing the spectrum and identifying available channels. This paper describes the issues related to the design of wideband signal paths and the decades-wide synthesis of carrier frequencies. A new CMOS low-noise amplifier topology for the range of 50 MHz to 10 GHz is introduced that achieves a noise figure of 2.9 to 5.7 dB with a power dissipation of 22 mW. Several multi-decade carrier generation techniques are proposed and a CMOS prototype is presented that exhibits a phase noise of -94 to -120 dBc/Hz at 1-MHz offset while consuming 31 mW.

And also the paper on "Progress and Challenges Towards Terahertz CMOS Integrated Circuits" is quite impressive:

Key components of systems operating at high millimeter wave and sub-millimeter wave/terahertz frequencies, a 140-GHz fundamental mode voltage controlled oscillator (VCO) in 90-nm CMOS, a 410-GHz push-push VCO with an on-chip patch antenna in 45-nm CMOS, and a 125-GHz Schottky diode frequency doubler, a 50-GHz phase-locked loop with a frequency doubled output at 100 GHz, a 180-GHz Schottky diode detector and a 700-GHz plasma wave detector in 130-nm CMOS are demonstrated. Based on these, and the performance trends of nMOS transistors and Schottky diodes fabricated in CMOS, paths to terahertz CMOS circuits and systems including key challenges that must be addressed are suggested. The terahertz CMOS is a new opportunity for the silicon integrated circuits community.

e2V delivers the largest focal plane array ever to be flown into space

2010-07-26T07:54:00.003+02:00

Space Daily (via OISBlog) reports on the delivery of 150 CCDs by e2V for the Gaia mission. Gaia's website includes some more info on the focal plane.

Engineers and social media

2010-07-25T18:30:00.001+02:00

There was an interesting discussion on engineers and social media at the latest episode of Synopsis' Conversation Central podcast.

2010-07-23T12:43:00.001+02:00

Tech-on briefly discusses phase detection and contrast autofocus, as Fujifilm announce their newest compact.

Variable shape pixels

2010-07-23T08:15:00.002+02:00

At the NIST's Journal of Research of the National Institute of Standards and Technology (via Science News and DPReview), a paper on "Precision and Accuracy in Scientific Imaging".

So... no 3D FPGAs?

2010-07-23T08:10:00.001+02:00

At EETimes: "FPGA startup Tier Logic folds".

Video interview of Pixim's CEO

2010-07-22T10:34:00.003+02:00

Via the System-Level Design blog, an interview with Pixim's CEO. With a very annoying use of stereo, btw.

Nano Image

2010-07-21T14:46:00.002+02:00

Related to the previous post, Carl Zeiss Nano Image Contest. You can vote for your favorite image.

The art of failure analysis

2010-07-18T09:59:00.001+02:00

Some pictures at the 2010 IPFA symposium web, showing what happens to semiconductor devices when something goes wrong.

Paper watch: A review of wireless multimedia sensor networks

2010-07-09T15:57:00.002+02:00

Again from Sensors Journal: "Wireless Multimedia Sensor Networks: Current Trends and Future Directions". A large part of the article is devoted to "camera motes". The abstract reads:

Wireless Multimedia Sensor Networks (WMSNs) have emerged and shifted the focus from the typical scalar wireless sensor networks to networks with multimedia devices that are capable to retrieve video, audio, images, as well as scalar sensor data. WMSNs are able to deliver multimedia content due to the availability of inexpensive CMOS cameras and microphones coupled with the significant progress in distributed signal processing and multimedia source coding techniques. In this paper, we outline the design challenges of WMSNs, give a comprehensive discussion of the proposed architectures, algorithms and protocols for the different layers of the communication protocol stack for WMSNs, and evaluate the existing WMSN hardware and testbeds. The paper will give the reader a clear view of the state of the art at all aspects of this research area, and shed the light on its main current challenges and future trends. We also hope it will foster discussions and new research ideas among its researchers.

Energy harvesting from muscles

2010-07-09T15:29:00.001+02:00

Nanowerk reports on work done at GeorgiaTech to harvest energy from heartbeat and breathing. Includes this video:

Paper watch: A review of microfluidic systems for biosensing

2010-07-09T14:56:00.004+02:00

From the open access Sensors Journal: "Microfluidic systems for biosensing". The abstract reads:

In the past two decades, Micro Fluidic Systems (MFS) have emerged as a powerful tool for biosensing, particularly in enriching and purifying molecules and cells in biological samples. Compared with conventional sensing techniques, distinctive advantages of using MFS for biomedicine include ultra-high sensitivity, higher throughput, in-situ monitoring and lower cost. This review aims to summarize the recent advancements in two major types of micro fluidic systems, continuous and discrete MFS, as well as their biomedical applications. The state-of-the-art of active and passive mechanisms of fluid manipulation for mixing, separation, purification and concentration will also be elaborated. Future trends of using MFS in detection at molecular or cellular level, especially in stem cell therapy, tissue engineering and regenerative medicine, are also prospected.

An implantable miniature telescope

2010-07-07T10:06:00.002+02:00

This is pretty cool: "FDA Approves VisionCare's Implantable Miniature Telescope".

Paper watch: SPADs for fluorescence

2010-07-07T09:54:00.003+02:00

An open access paper at the Virtual Journal for Biomedical Optics: "Real-time fluorescence lifetime imaging system with a 32 × 32 0.13μm CMOS low dark-count single-photon avalanche diode array".

A compact real-time fluorescence lifetime imaging microscopy (FLIM) system based on an array of low dark count 0.13μm CMOS single-photon avalanche diodes (SPADs) is demonstrated. Fast background-insensitive fluorescence lifetime determination is achieved by use of a recently proposed algorithm called ‘Integration for Extraction Method’ (IEM) [J. Opt. Soc. Am. A 25, 1190 (2008)]. Here, IEM is modified for a wider resolvability range and implemented on the FPGA of the new SPAD array imager. We experimentally demonstrate that the dynamic range and accuracy of calculated lifetimes of this new camera is suitable for widefield FLIM applications by imaging a variety of test samples, including various standard fluorophores covering a lifetime range from 1.6ns to 16ns, microfluidic mixing of fluorophore solutions, and living fungal spores of Neurospora Crassa. The calculated lifetimes are in a good agreement with literature values. Real-time fluorescence lifetime imaging is also achieved, by performing parallel 32 × 16 lifetime calculations, realizing a compact and low-cost FLIM camera and promising for bigger detector arrays.

Paper watch: review of state-of-the-art on graphene transistors

2010-07-07T09:51:00.003+02:00

At Nature Nanotechnology there's a nice article (after paywall, unfortunately) reviewing the state of the art in graphene transistors. From the abstract:

Graphene has changed from being the exclusive domain of condensed-matter physicists to being explored by those in the electron-device community. In particular, graphene-based transistors have developed rapidly and are now considered an option for post-silicon electronics. However, many details about the potential performance of graphene transistors in real applications remain unclear. Here I review the properties of graphene that are relevant to electron devices, discuss the trade-offs among these properties and examine their effects on the performance of graphene transistors in both logic and radiofrequency applications. I conclude that the excellent mobility of graphene may not, as is often assumed, be its most compelling feature from a device perspective. Rather, it may be the possibility of making devices with channels that are extremely thin that will allow graphene field-effect transistors to be scaled to shorter channel lengths and higher speeds without encountering the adverse short-channel effects that restrict the performance of existing devices. Outstanding challenges for graphene transistors include opening a sizeable and well-defined bandgap in graphene, making large-area graphene transistors that operate in the current-saturation regime and fabricating graphene nanoribbons with well-defined widths and clean edges.

Introduction to DSP for intelligent sensor applications

2010-07-07T09:48:00.001+02:00

At Embedded.com there's a nice introduction to DSP for intelligent sensor applications: part 1, part 2, part 3.

Non-contact biosensors for EEG and ECG

2010-07-06T07:50:00.005+02:00

At MIT's Technology Review, an article about research at UCSD on capacitive sensors for EEG and ECG.

Chi's sensor is barely larger than a quarter, and when multiple sensors are embedded in material and wired together, they create a portable monitor that patients can wear over clothing as they go about their daily routine. This could mean increased monitoring time and better compliance from patients.

Update 3: Their latest paper actually has quite nice results. I will take my reservations back :-).

Update 2: My wrong. They do have recent papers about the work which show good performance, but no mention on how they deal with motion performance, plus noise numbers seem a bit high.

Update: The group has a paper from 2007 on what looks like a very similar system. I could not find any scientific publication on the new work, so I'll join some colleagues on my skepticism for this development.

It's official: there's nothing graphene can't do

2010-07-05T16:23:00.002+02:00

The latest proof: "Antibacterial paper made from graphene".

Free PCB design software

2010-07-05T12:58:00.003+02:00

RS offers DesignSpark, a fully free PCB design software. The only thing you need to do in order to use it is join their online community.

Paper watch: CMOS-compatible optical integrator

2010-07-02T09:37:00.002+02:00

At Nature Communications, but open access: "On-chip CMOS-compatible all-optical integrator". The abstract reads:

All-optical circuits for computing and information processing could overcome the speed limitations intrinsic to electronics. However, in photonics, very few fundamental 'building blocks' equivalent to those used in multi-functional electronic circuits exist. In this study, we report the first all-optical temporal integrator in a monolithic, integrated platform. Our device—a lightwave 'capacitor-like' element based on a passive micro-ring resonator—performs the time integral of the complex field of an arbitrary optical waveform with a time resolution of a few picoseconds, corresponding to a processing speed of ∼200 GHz, and a 'hold' time approaching a nanosecond. This device, compatible with electronic technology (complementary metal-oxide semiconductor), will be one of the building blocks of next-generation ultrafast data-processing technology, enabling optical memories and real-time differential equation computing units.

More research towards reliable graphene transistors

2010-07-02T09:34:00.002+02:00

Seen first at nanowerk here, the paper at nature communications (after paywall) is here: "Gate-controlled electron transport in coronenes as a bottom-up approach towards graphene transistors". The abstract reads:

Graphene is considered to be a large aromatic molecule, the limiting case of the family of polycyclic aromatic hydrocarbons. This fascinating two-dimensional material has many potential applications, including field effect transistors (FETs). However, the graphene sheets in these devices have irregular shapes and variable sizes, and contain various impurities and defects, which are undesirable for applications. Moreover, the bandgap of graphene is zero and, consequently, the on/off ratios of graphene FETs are small, making it difficult to build logic circuits. To overcome these difficulties, we report here a bottom-up attempt to fabricate nanoscale graphene FETs. We synthesize structurally well-defined coronene molecules (consisting of 13 benzene rings) terminated with linker groups, bridge each molecule to source and drain electrodes through the linkers, measure conductance and demonstrate the FET behaviour of the molecule.

Paper watch: Semiconducting polymer photodetectors

2010-07-01T14:58:00.004+02:00

New paper at the open access Sensors Journal: "Semiconducting Polymer Photodetectors with Electron and Hole Blocking Layers: High Detectivity in the Near-Infrared". The abstract reads:

Sensing from the ultraviolet-visible to the infrared is critical for a variety of industrial and scientific applications. Photodetectors with broad spectral response, from 300 nm to 1,100 nm, were fabricated using a narrow-band gap semiconducting polymer blended with a fullerene derivative. By using both an electron-blocking layer and a hole-blocking layer, the polymer photodetectors, operating at room temperature, exhibited calculated detectivities greater than 10¹³cm Hz^1/2/W over entire spectral range with linear dynamic range approximately 130 dB. The performance is comparable to or even better than Si photodetectors.

Imaging satellites helping with the Gulf oil spill efforts

2010-07-01T09:52:00.002+02:00

At SPIE, an overview of the instruments and research groups helping to combat the Gulf oil spill.

MSc thesis position at imec

2010-07-01T09:49:00.002+02:00

If someone's interested, here's info on a new MSc thesis position at imec on CMOS circuits for bio-photonics:

"Low Noise/Low Power Electronics for an Optical Glucose Sensor"

Description:
One of the most important requirements of implantable sensors is operation with very low power consumption. When such a sensor requires high performance for its correct operation, the power consumption becomes the most critical parameter of the design because of (1) battery size and frequency of replacement and (2) risk of local tissue heating (resulting in tissue irritation and inflammation).

This project aims at the design of an ultra low power CMOS readout circuit for an optical glucose sensor, as well as the driver electronics for the light source. The work involves:
* Analysis of the complete system: light source + optical detector for optimum power operation.
* Design of the sensor readout circuit.
* Design of the driver electronics for the light source.

The candidate must have followed courses on analog CMOS circuit design. Familiarity with the operation of photonic devices and with the Cadence design environment will be highly valued.

Degree:
This work is defined as thesis work for a MSc in Electronic Engineering

Duration:
The duration of the internship will be at least 6 months.

Contact:
David San Segundo Bello (David.SanSegundoBello@imec.be)

Hazardous substances

2010-07-01T09:46:00.003+02:00

There are two interesting posts at EDN's critical links blog on recent ROHS developments:

And while we are in the subject, other substances used in electronic components which are hazardous but in a different way.

Tomoyuki Suzuki from Sony on their image sensor business

2010-06-30T21:42:00.001+02:00

At Tech On: "Winning in Imaging Devices, The Last Bastion".

The first integral imaging camera?

2010-06-30T08:30:00.001+02:00

Over at Futurepicture: "P.P. Sokolov’s Historical Work on Light Field Photography/Integral Imaging".

Paper watch: Using DSLRs for cancer detection

2010-06-30T08:26:00.002+02:00

At PLoS ONE: "A Fiber-Optic Fluorescence Microscope Using a Consumer-Grade Digital Camera for In Vivo Cellular Imaging" (first seen here).

Fun game

2010-06-29T08:11:00.001+02:00

A fun nerdy game: arXiv vs. snarXiv (found here).

What is a patent?

2010-06-28T20:49:00.001+02:00

From EETimes: "Supreme Court dodges decision of what is a patent".

"In general it was a pro-patenting ruling, and that collective sigh of relief you hear is from the software and biotech communities," said Reines. "A vote for the transformation test would have narrowed patents substantially for the software and biotech industries," he said.

Which way forward?

2010-06-28T17:00:00.004+02:00

Harry "the ASIC guy" has a series of (so far) three interesting and thoughtful blog posts on the future direction for EDA:

High performance ADC PCB design

2010-06-28T08:28:00.001+02:00

A very comprehensive article from TI on how to design the PCB for a high performance SAR ADC: "Optimizing SAR ADC performance by proper PCB layout".

Movable brain-machine interface

2010-06-25T17:34:00.002+02:00

Here's a nice post at the Neurophilosophy blog about a movable brain-machine interface:

[...]
The device consists of an array of microelectrodes that are fabricated, along with a number of microscopic mechanical components, onto a silicon wafer. Each microelectrode is controlled by four microactuators, one each to deactivate a release-up lock and release-down lock, and one each to move the electrode up and down. The actuators work using electro-thermal strips and are coupled to a ratchet system that drives the centre shuttle of each electrode up or down.
[...]

The original article is here.

And related, at Mind Hacks, a link to an article on the US Army'svision for brain-machine interfaces.

Paper watch: Effects of Negative-Bias Operation and Optical Stress on Dark Current in CMOS Image Sensors

2010-06-23T10:39:00.001+02:00

From the latest IEEE Transactions on Electron Devices, a paper from Hamamatsu on dark current mechanisms in pinned photodiodes: "Effects of Negative-Bias Operation and Optical Stress on Dark Current in CMOS Image Sensors". The abstract reads:

A negative-bias operation of the transfer gate has revealed a major origin of dark current defects of CMOS image sensors. Charge injection from the photodiode to the substrate at the negative-bias operation has been avoided by an improved well structure. A strong visible light has been observed to cause damage with an increase in the dark current under the normal operating condition, and the damage has been annealed in the power-off mode. This indicates that the strong light possibly causes a threshold voltage shift, which is explained by the photon-assisted tunneling or emission mechanisms. Multiple stress-and-anneal cycles have been found to cause an optical hardening effect, which can be explained by immobile trapped holes.

Graphene coming through

2010-06-23T08:12:00.004+02:00

A couple of this week's graphene development announcements/papers:

A paper at Applied Physics Letters on graphene films for supercapacitors. Abstract: "This study reports the preparation of ultrathin, transparent graphene films for use in supercapacitor applications. The surface morphology of the films was investigated by scanning electron microscopy and transmission electron microscopy, revealing a very homogeneous surface with intimate contact between graphene sheets. Electrochemical characterization demonstrated nearly ideal electrical double layer capacitive behavior. The capacitance obtained from charge-discharge analysis is 135 F/g for a film of approximately 25 nm which has a transmittance of 70% at 550 nm and a high power density of 7200 W/kg in 2 M KCl electrolyte."
Advances on simplifying manufacturing nano-electronics based on graphene and nanowires: "[...]. They have devised a simple and quick one-step process based on thermochemical nanolithography (TCNL) for creating nanowires, tuning the electronic properties of reduced graphene oxide on the nanoscale and thereby allowing it to switch from being an insulating material to a conducting material."

DAC 2010 coverage collected

2010-06-23T08:10:00.001+02:00

Sean Murphy is collecting blog posts, articles etc. regarding the DAC2010 conference here.

UMC gets into 3D stacking

2010-06-22T08:20:00.002+02:00

The announcement at EETimes. Interesting that their plan is to apply it from the 28nm node onwards.

DAC wrap-up

2010-06-22T08:08:00.004+02:00

DAC 2010 is finished. You can find a lot of information on the really good conference website. Don't miss the keynote's videos (but be careful, they tend to crash Firefox...).

A couple of wrap-ups:

From Olivier Coudert.
From Richard Goering (very active correspondent).

more 3D FPGAs

2010-06-21T15:00:00.001+02:00

...and now also Toshiba:

[...] In the case of the 3D FPGA, SRAMs for configuration are formed by using amorphous Si TFT technology and stacked on a nine-layer CMOS chip that has copper (Cu) wiring and logic circuits for user logic. As a result, the chip area of the FPGA can be reduced to about half that of existing FPGAs.

SPIE´s 2010 Security and Defense program online

2010-06-21T09:13:00.002+02:00

The programs for the different parallel conferences of SPIE´s 2010 Security+Defense meeting are available here. Lots of IR and THz/mm wave imaging papers and posters, and a couple of presentations by Tower Jazz on their technology offers.

Recent "more Moore" announcements

2010-06-20T10:22:00.002+02:00

If we follow the naming convention of "more Moore" for those initiatives which push transistor scaling deeper into the nanometer regime, the last couple of weeks had some interesting new developments. In no particular order:

Toshiba shows its efforts for using nantotubes as transistor channels to achieve 16nm transistors.
Intel shows its use of "air gaps" (actually vacuum gaps) for metal insulation in 22nm technology.
Macronix announces its 3-D NAND flash (also at EETimes). For those with IEEEXplore access, one of the papers describing the technology during its development, from IEDM 2005, can be found here, showing that developments in this area take several years to reach the production stage. The abstract reads: "A bandgap engineered SONOS with greatly improved reliability properties is proposed. This concept is demonstrated by a multilayer structure of O1/N1/O2/N2/O3, where the ultra-thin "O1/N1/O2" serves as a non-trapping tunneling dielectric, N2 the high-trapping-rate charge storage layer, and O3 the blocking oxide. The ultra-thin "O1/N1/O2" provides a "modulated tunneling barrier" - it suppresses direct tunneling at low electric field during retention, while it allows efficient hole tunneling erase at high electric field due to the band offset. Therefore, this BE-SONOS offers fast hole tunneling erase, while it is immune to the retention problem of the conventional SONOS. With a N⁺-poly gate, we achieve self-convergent erased Vt ~3 V, suitable for NOR flash application. On the other hand, by using a P⁺-poly gate, a depletion mode device (Vt <> 6 V) is achieved, ideal for MLC-NAND application. Excellent performance and reliability for both applications are demonstrated. Furthermore, with this simple structure and no new materials BE-SONOS is readily manufacturable."

3D FPGAs

2010-06-16T07:56:00.002+02:00

It seems that the big boys are putting their weight on this topic, and Xilinx and Actel are looking at 3D-stacked FPGAs, as this article points out.

Incidentally, this line almost at the end of the article made me wonder:

[...] Under the covers, there are two technical ways to make this all possible, according to an ARM insider. “The first is for TSVs at similar pitch to solder bumps (about 50nm)". [...]

Oh wait, do you mean it was a typo?

Paper watch: Precise control of thermal conductivity at the nanoscale through individual phonon-scattering barriers

2010-06-10T11:28:00.003+02:00

Seen at this German-language post at nanowerk, an interesting paper at Nature Materials: "Precise control of thermal conductivity at the nanoscale through individual phonon-scattering barriers". The abstract reads:

The ability to precisely control the thermal conductivity (κ) of a material is fundamental in the development of on-chip heat management or energy conversion applications. Nanostructuring permits a marked reduction of κ of single-crystalline materials, as recently demonstrated for silicon nanowires. However, silicon-based nanostructured materials with extremely low κ are not limited to nanowires. By engineering a set of individual phonon-scattering nanodot barriers we have accurately tailored the thermal conductivity of a single-crystalline SiGe material in spatially defined regions as short as ∼15 nm. Single-barrier thermal resistances between 2 and 4×10⁻⁹ m² K W⁻¹ were attained, resulting in a room-temperature κ down to about 0.9 W m⁻¹ K⁻¹, in multilayered structures with as little as five barriers. Such low thermal conductivity is compatible with a totally diffuse mismatch model for the barriers, and it is well below the amorphous limit. The results are in agreement with atomistic Green’s function simulations.

Videos at EETimes

2010-06-09T08:08:00.002+02:00

EETimes hosts a large number of videos at their website ranging from demos, interviews and panels, such as the 2010 ESC SV Medical Electronics Panel.

PANalytical's PIXcel3D detector

2010-06-07T15:43:00.002+02:00

It always makes you happy when something you have been a part of is successful. I read today that PANalytical has introduced in the market the first X-ray diffractometer with a hybrid X-ray pixel detector. I was there at the beginning of this work and it feels good to see it's finally out there.

Towards silicene

2010-06-04T08:56:00.003+02:00

What if you could have all the advantages of graphene, but starting from Silicon (with the additional advantages that his means) instead of Carbon? Silicene might be the answer, and there are hints that it might be feasible, as this Applied Physics Letter shows: "Graphene-like silicon nanoribbons on Ag(110): A possible formation of silicene".

Scanning tunneling microscopy (STM) and ab initio calculations based on density functional theory (DFT) were used to study the self-aligned silicon nanoribbons on Ag(110) with honeycomb, graphene-like structure. The silicon honeycombs structure on top of the silver substrate is clearly observed by STM, while the DFT calculations confirm that the Si atoms adopt spontaneously this new silicon structure.

Although some people think it is not possible.

Paper watch: Nanostructured materials for photon detection

2010-06-04T08:49:00.002+02:00

Inside the most recent Nature Nanotechnology journal (behind paywall), a nice overview of the progress in nanostructured materials for photo-detection. The abstract reads:

The detection of photons underpins imaging, spectroscopy, fibre-optic communications and time-gated distance measurements. Nanostructured materials are attractive for detection applications because they can be integrated with conventional silicon electronics and flexible, large-area substrates, and can be processed from the solution phase using established techniques such as spin casting, spray coating and layer-by-layer deposition. In addition, their performance has improved rapidly in recent years. Here we review progress in light sensing using nanostructured materials, focusing on solution-processed materials such as colloidal quantum dots and metal nanoparticles. These devices exhibit phenomena such as absorption of ultraviolet light, plasmonic enhancement of absorption, size-based spectral tuning, multiexciton generation, and charge carrier storage in surface and interface traps.

More YouTube and image sensing

2010-06-03T08:26:00.004+02:00

Looking at the related videos from the previous post, I find out about this cornucopia of videos from GoogleTechTalks' PhotoTechEdu series on photography and image sensing in general. Enjoy...

Altera FPGA and WDR image sensors

2010-06-03T08:04:00.003+02:00

At Altera's YouTube channel there's this video on using FPGAs with WDR sensors. The demo uses an Aptina sensor.

Paper watch: Illumination-based synchronization of high speed image sensors

2010-06-02T18:00:00.001+02:00

At the open access Sensors journal, an interesting application of the PLL concept from Tohoku University: "Illumination-Based Synchronization of High-Speed Vision Sensors".

To acquire images of dynamic scenes from multiple points of view simultaneously, the acquisition time of vision sensors should be synchronized. This paper describes an illumination-based synchronization method derived from the phase-locked loop (PLL) algorithm. Incident light to a vision sensor from an intensity-modulated illumination source serves as the reference signal for synchronization. Analog and digital computation within the vision sensor forms a PLL to regulate the output signal, which corresponds to the vision frame timing, to be synchronized with the reference. Simulated and experimental results show that a 1,000 Hz frame rate vision sensor was successfully synchronized with 32 μs jitters.

More on using visible light for data communication

2010-06-01T07:58:00.002+02:00

Tech-on carries another news item about using visible light for data transmission:

The visible light communication system was developed by Outstanding Technology Co., Ltd. of Japan, a technology start-up. Performance in the lab has achieved transmission of a digital signal at 160Mbit/s over a 20cm distance with a single LED, and 13km transmission of a 1kbit/s-equivalent analog voice signal.
[...]
The firm combined a silver mirror with the photoreceptor to boost sensitivity and speed simultaneously. Concretely, light not directly received by the photoreceptor is reflected from the surrounding parabolic silver mirror into it.
The larger effective receptor area made it possible to use a high-speed (400MHz cut-off) photoreceptor and still achieve a high sensitivity of 1.5A/W to 2A/W output through 450nm wavelength. This is roughly ten times more sensitive than other photoreceptors with comparable waveband and speed.
[...]
While details of the new technology are still unknown, it was revealed that the modulation circuit design was based on accurate measurement of white LED resistive, capacitive and inductive components, making the success possible.

Omnivision Earnings Call

2010-05-28T12:45:00.002+02:00

From seeking alpha, a transcript of Ominivision's earnings call. Choice quotes:

In our later session, Bruce will discuss in greater details our leadership role in strengthening transition from a sensing to an imaging company.
[...]
As we noted last quarter, our first BSI pixel, the OmniBSI, continues to ramp in mass production with the increase accelerating rapidly as we enter our first quarter of fiscal 2011. In fact, the growth we anticipate in BSI shipments during the coming quarter is so profound that we have challenged our entire supply chain to respond. And they have. We have worked closely with each participate in each stage of production cycle to meet the quickly emerging demand for our BSI devices as we expand from simple volumes to multi-million unit shipments.
[...]
We now anticipate that we will ramp OmniBSI during the first fiscal quarter and beyond in volumes exceeding even our own expectations. In the fiscal 2010 fourth quarter, we shipped approximately 125 million units at an average selling price of $1.26. This compares with approximately 130 million units shipped in the third quarter at an average selling price of $1.18. The sequential increase in ASP during the fourth quarter reflects a favorable shift to a higher-resolution product mix.
[...]
Betsy Van Hees - Wedbush Securities Inc.
Given that you guys have done such a fantastic job in terms of your technology, as you're looking at the competitive landscape, how far is your competitive lead now above your competitors? And can you kind of give us an idea of, in terms of ranking, when they're going to be catching up to you, if at all?
Bruce Weyer
Yes, so a big portion of our technology we discussed is our pixel technology underneath the sensors. And in February, we announced our second-generation BSI pixel technology and we have been in development at BSI for almost four years now with our key technology partner, TSMC. And so first-generation BSI is ramping very significantly for us. We see significant advancements coming in our second-generation BSI-2. And just now, you're starting to see our competitors discuss BSI products for the open market in mobile phones and those areas. So we think we have a pretty substantial lead in that development.
Betsy Van Hees - Wedbush Securities Inc.
So when you look into competition though, how far does that lead stay ahead? Is anyone catching you? Or are you just going to continue to dominate the field in this area?
Bruce Weyer
So we hear of competitors starting to potentially sample products, but sampling products and meeting the performance goals of our customers could very well be different things. It does take a while to perfect these types of technologies. So I'm not in a position to fully state where they're at in their development process, but based on our sampling window to strong leadership position, we think we're in a pretty good shape.
Ray Cisneros
And just another comment about that. It's going from sampling to mass production in tens of millions of units per quarter, that's the big learning curve that everybody's got to go through. And as Bruce mentioned, it's difficult to understand where our competition is in that curve. But suffice it to say from our side, it's a learning curve that's not easy and it's not overnight.
[...]
Yair Reiner - Oppenheimer & Co. Inc.
And then, if you could give us an update in terms of 300-millimeter transition in the future?
Bruce Weyer
300-millimeter is our base technology for our second-generation BSI-2 architectures. So we are in 300-millimeter, as we speak, and we're sampling products out of that. Typically, design cycles for our end customers take six to 12 months. So that technology will be more targeted for a 2011-type ramp in realistic volumes. And also, it's a 300-millimeter platter, so the available supply is broad upfront. So we don't see any challenges in whatsoever in ramping our 300-millimeter technology to our end customers.

Directory of computer vision research groups

2010-05-28T08:21:00.003+02:00

Computer Vision Central maintains a list of computer vision research groups around the world.

Matlab on your phone

2010-05-28T07:47:00.001+02:00

It starts with Apple products only, though.

Industry Keynotes by Mentor Graphics

2010-05-27T12:47:00.001+02:00

Thanks to image sensors world I've discovered this resource in Mentor Graphics with several keynote presentations delivered by Mentor's CEO.

Noise, Dynamic Range and Bit Depth in Digital SLRs

2010-05-27T08:05:00.002+02:00

Professor Emil Martinec at the University of Chicago has a nice overview of noise in image sensors at his website. A nice addition to Albert Theuwissen's ongoing series at his own blog, which started here.

NHK shows a full-color organic image sensor

2010-05-26T21:12:00.001+02:00

Not many details, but Tech-on reports on NHK's organic image sensor.

Another OCT system approved by the FDA

2010-05-26T13:13:00.003+02:00

I recently mentioned this one from LightLab, and now medgadget reports that Optovue's OCT system has also been approved. It's aimed at a different application, but it uses a similar technique.

Fujitsu´s 56Gs/s ADC

2010-05-26T13:05:00.004+02:00

I just found out that Fujitsu has a webpage with some documentation (in particular this tecknology backgrounder and this very nice presentation) about their 56 GS/s ADC in 65nm CMOS.

Maxim´s medical solutions guide

2010-05-26T08:26:00.002+02:00

Via Paul Rako's blog at EDN, a link to Maxim's 220 pages medical solutions guide.

Micromirrors

2010-05-25T08:31:00.003+02:00

First: a new (for me) way of driving micro-mirror arrays using a photodiode array, at this paper from Applied Physics Letters (sorry, behind paywall): "An all optically driven integrated deformable mirror device". The abstract reads:

We demonstrate a technique for actuating micromirrors vertically cascaded on wafer fused GaAs-GaP photodiodes. Unlike traditional actuation schemes, the electrostatic drive of the individual capacitive actuators is addressed optically in this device. Vertical mirror displacements of up to 500 nm were observed using interferometry while addressing the photodetectors with a 5 mW optical signal. Microlenses were used to address a 900 pixel device with patterned conductive pillars and thin film load resistors for each actuator-detector element. This approach can enable realization of faster and denser adaptive optics wave front corrector arrays.

Second: from Coventer's design blog, a look at the design of a resonant 2D scanning micromirror MEMS device.