Viterbi Faculty of Electrical Engineering, Technion
Study of 2-D imagers and LiDAR based on the CMOS SPAD detectors
The need for high frame rate and low light imaging for medical, military, and civil purposes has increased significantly in recent years. Moreover, photography is undergoing a paradigm shift to high resolution three-dimensional imaging. This gives rise to the need to develop a very fast and sensitive sensor to meet these requirements simultaneously. Key requirements for this sensor are low-cost manufacturing and integration in systems on chip. Thus, it requires a low-cost, mature CMOS process. Achieving a very fast and sensitive imager using CMOS technology requires novel architectures and circuit designs. Our goal in this thesis is to develop a cutting-edge sensor with accompanying novel CMOS architectures and circuit designs to make modern imaging a common-day reality. This research focuses on a CMOS Single Photon Avalanche Diode (SPAD) sensor with near infra-red enhanced performance. This sensor offers many advantages in terms of single photon response, high gain, read-out noise immunity, and fast timing response. It is the best candidate for high-resolution Light Direction and Range (LiDAR), which is required today in every advanced driver-assistance system. In fact, a goal of this research is to adapt the above sensor to two-dimensional imager and LiDAR, working in sunlight. In these applications, high background conditions (clutter) require correct electrooptical design as well as the sensor optimization in terms of signal-to-noise ratio and saturation level. The main contributions of this research are: A novel, monolithic, small-area, and low-power active-reset approach for near infra-red single ended SPAD. This approach provides a dramatic reduction in the SPAD’s dead time, achieving an enhancement in saturation photon rate for this type of SPAD. The higher-saturation photon rate increases the imager’s immunity to high solar background. Such high background is particularly problematic in sunny days. A worldwide, pioneering, 15 kfps, 64 x 64, passive, two-dimensional gun muzzle flash detection imager, based on CMOS SPAD pixels was developed and tested in a real firing experiment on a sunny day. A novel imager pixel architecture, equipped by integrated 8-bit memory, enables parallel processing and global shutter readout. A novel, long-range, time-of-flight LiDAR architecture, based on silicon photo multiplier with simultaneous photon-counting (intensity) and photon-timing (distance) abilities was developed and taped-out. The LiDAR was implemented as a single chip with integrated 500 psec resolution time to digital converter. * PhD student supervised by Prof. Yael Nemirovsky.
Date: Mon 04 Mar 2019
Start Time: 14:30
End Time: 15:30
1061 | Electrical Eng. Building