Photon-Counting Jot Devices for Quanta Image Sensor

The quanta image sensor (QIS) is a third-generation solid-state digital imaging technology. The photoelements, called "jots," are specialized to have photon-counting sensitivity at room temperature without using electron avalanche multiplication. A QIS may contain billions of jots operating at 1000fps or higher and by counting every single photon at a high speed, numerous exciting features can be enabled. This novel technology can naturally fit the needs of high-speed and high-resolution accurate photon-counting imaging for scientific imaging, space imaging, security, low-light imaging and other applications. A proof of concept for the jot device was successfully developed and demonstrated in 2015 and 2017. Using the innovative jot structure, sub-0.2e-r.m.s. read noise was demonstrated with a manifestly improved conversion gain at room temperature. For the first time, accurate photon counting was realized with photodetectors fabricated in a standard CMOS process without the use of amplification from electron avalanche multiplication. This thesis covers the development of photon-counting jot devices for the QIS. The design of the jot was one of the most difficult challenges in the implementation of the QIS. These difficulties included the reduction of read noise to enable photon-counting while shrinking the size of the jots and optimizing other specifications that affect the accuracy of photon-counting (dark current, quantum efficiency, etc.). The work presented in this thesis covers all of these topics, while the emphasis is placed on the most challenging hurdle: the reduction of read noise towards the deep sub-electron read noise region to enable photon-counting