SWIR Quantum Dot Triodes

Nature paper "Silicon: quantum dot photovoltage triodes" by Wen Zhou, Li Zheng, Zhijun Ning, Xinhong Cheng, Fang Wang, Kaimin Xu, Rui Xu, Zhongyu Liu, Man Luo, Weida Hu, Huijun Guo, Wenjia Zhou & Yuehui Yu from Chinese Academy of Sciences and ShanghaiTech University presents a concept of 1550nm photodetector with internal gain:

"Silicon is widespread in modern electronics, but its electronic bandgap prevents the detection of infrared radiation at wavelengths above 1,100 nanometers, which limits its applications in multiple fields such as night vision, health monitoring and space navigation systems. It is therefore of interest to integrate silicon with infrared-sensitive materials to broaden its detection wavelength. Here we demonstrate a photovoltage triode that can use silicon as the emitter but is also sensitive to infrared spectra owing to the heterointegrated quantum dot light absorber. The photovoltage generated at the quantum dot base region, attracting holes from silicon, leads to high responsivity (exceeding 410 A·W−1 with Vbias of −1.5 V), and a widely self-tunable spectral response. Our device has the maximal specific detectivity (4.73 × 1013 Jones with Vbias of −0.4 V) at 1,550 nm among the infrared sensitized silicon detectors, which opens a new path towards infrared and visible imaging in one chip with silicon technology compatibility."

SOL Presents its Lens-Free Sensor Solutions

SOL Inc. presents its IEC-standardized lensless biosensor solutions:

Actlight CEO Considers Selling the Company

Verve.vc publishes an interview with Serguei Okhonin, Actlight CEO and co-founder. Few quotes:

Q: So how does an IP company such as ActLight actually work?

A: We started with an idea and developed it up to the point where we could file patents. The goal, of course, is to license the technology to big semiconductor companies that integrate it into their offering, which they can eventually sell to the big consumer brands we all know. What we do is research and refine our technology to the point that we can provide potential customers with prototypes that should, ideally, convince them of the merits of our sensor. When we achieve this, our job is done. We then basically just provide support.

Q: Let me guess: Convincing big semiconductor companies isn’t that easy.

A: Our potential customers are global market leaders, they have tens of thousands of employees and decades of experience in their field. Now imagine that a small startup from Lausanne comes up to them and says: Look guys, our detector performs better than what you have developed. The first thing they tell you is: That’s impossible. It takes many meetings and a lot of time to convince them otherwise. And then, they do a very thorough due diligence. They will spend more than a year to ascertain the merits of new technology, it is a long process. But once they have done that, and decide to move forward, these companies move very quickly. They have the manpower, the infrastructure, the sales organization, the relationships with their customers… they can bring a product to the mass market at a speed that no startup can match.

Q: Where do you stand in the process you just described?

A: For an IP company like ActLight, the most important achievement is what I call the industrial proof of technology, which means, that a mass-market product incorporates the technology we have developed. We have achieved this milestone now. We licensed our technology to a semiconductor company, the number 1 worldwide, which is building a heart-rate monitor for hearable devices. Thanks to our invention, power consumption is drastically reduced and a high level of miniaturization is achieved. Working samples are already at end customers and, in 2022, mass production starts.

Q: With a use case that will hit the market soon and others that sound promising, ActLight must have appeared on the radar of tech companies by now.

A: After 10 years, we need to think about the future of the company, and there are basically two options. Do we want to grow and pursue more projects, or do we want to sell the company? Recently, we have started to get approached by potential buyers. Of course, such approaches out of the blue need to be examined very well, but it doesn’t surprise me that this happens now.

Q: Because of the traction or what you called industrial proof of technology?

A: Not only that, the M&A activity in the semiconductor industry is incredibly intense at the moment. The sector is red hot. Hardware stocks have reached new highs, and the shortage of semiconductors is talked about a lot. There is an urgency to invest that I haven’t seen in the past 3 decades, it’s insane.

TheBusinessTime publishes an article about Actlight in-ear vital signs monitoring solution.

Free Ebook: The Latest Development Trends in CMOS Image Sensors

Techinsights releases a free ebook "The latest development trends in CMOS Image Sensors."  This is a recap of a presentation given by Ziad Shukri at IISW 2021:

• the latest analysis and trends of CMOS image sensors - resolution, pixel pitch, chip stacking and die configuration
• active silicon thickness and pixel aspect ratio trends
• trends and comparative analysis on ToF sensors, including both Front- and Back-illuminated, as well as recent NIR-optimized sensors
• CIS trends for emerging applications and future challenges

Sony 32MP Sensor Uses 22nm Process

Sony IMX709 sensor used in the new Oppo Reno 7 smartphone front camera is claimed to be Sony's first sensor based on 22nm process:

Atomic Layer Deposition in Image Sensor Manufacturing

Yole Developpement report "ALD equipment market surging with 12% CAGR to reach $680M in 2026, penetrating all More-than-Moore applications" states that CIS is by far the largest market for Atomic Layer Deposition systems:

Samsung to Adopt CSP for Low Resolution Sensors

TheElec: Samsung is to use chip-scale packaging (CSP) to reduce the cost of its low resolution image sensors starting 2022, according to TheElec sources. Currently, Samsung uses chip on board (COB) approach for all sensors.

CSP is done at the wafer level, unlike COB, resulting in increased productivity and lower assembly clean room requirements. 

The downside of CSP can only be done in lower resolution image sensors. Most higher resolution image sensors are manufactured with COB. TheElec sources say that CSP can support up to 2MP resolution at as of now.

Large Format 288MP Global Shutter Sensor

Korea-based company Syncron presents its first CIS product - 288MP sensor with 3.5um global shutter pixels. Syncron started a long time ago as a spin-off from Kodak Korea and specializes in high-speed and high-resolution industrial digital cameras. The company has been in machine vision camera distribution business, and the new DCS288M sensor appears to be its first CIS product.

Thanks to TL for the link!

Hynix Presents All-Directional PDAF Pixel

EETimes: SK Hynix presents A4C quad pixel PDAF technology:

"The structure of the A4C sensor is shown in figure 1. Similar to the conventional Quad sensor, it has a photodiode that converts light into an electric current and a color filter that selectively absorbs certain light wavelength. Unlike the Quad sensor, however, its structure is made up of one micro lens on each group of four of the same color of pixels in the top left (TL), top right (TR), bottom left (BL), and bottom right (BR) corners.

Compared to existing PDAF technology, the A4C sensor can calculate disparity at every pixel. It means accuracy is high and that it can secure more than 10 times the accuracy in low-light environment of less than 10 lux. Unlike conventional PDAF technology, which leverages binocular disparity, the A4C sensor leverages the disparity of four pixels on the top and bottom and the left and right corners under the micro lens. Therefore, its focus detection performance of subjects of horizontal or vertical directions is outstanding. Video demonstrates the performance gap between a conventional AF and A4C AF."

Smartphone DxOMark Score vs Silicon Area

Yole Developpement publishes its analysis "End-user performance does not correlate with main sensor resolution in ultra-premium flagships; bigger is not necessarily always better."

Entropy-Based Anti-Noise Method

Harbin Institute of Technology, China, publishes MDPI paper "An Entropy-Based Anti-Noise Method for Reducing Ranging Error in Photon Counting Lidar" by Mingwei Huang, Zijing Zhang, Jiaheng Xie, Jiahuan Li, and Yuan Zhao.

"Photon counting lidar for long-range detection faces the problem of declining ranging performance caused by background noise. Current anti-noise methods are not robust enough in the case of weak signal and strong background noise, resulting in poor ranging error. In this work, based on the characteristics of the uncertainty of echo signal and noise in photon counting lidar, an entropy-based anti-noise method is proposed to reduce the ranging error under high background noise. Firstly, the photon counting entropy, which is considered as the feature to distinguish signal from noise, is defined to quantify the uncertainty of fluctuation among photon events responding to the Geiger mode avalanche photodiode. Then, the photon counting entropy is combined with a windowing operation to enhance the difference between signal and noise, so as to mitigate the effect of background noise and estimate the time of flight of the laser pulses. Simulation and experimental analysis show that the proposed method improves the anti-noise performance well, and experimental results demonstrate that the proposed method effectively mitigates the effect of background noise to reduce ranging error despite high background noise."