Compact SPAD pixels with fast and accurate photon counting in the analog domain

作     者：Zhiqiang Ma Zhong Wu Yue Xu Zhiqiang Ma;Zhong Wu;Yue Xu

作者机构：College of Electronic and Optical Engineering&College of MicroelectronicsNanjing University of Posts and TelecommunicationsNanjing 210023China National and Local Joint Engineering Laboratory of RF integration&Micro-Assembly TechnologyNanjing 210023China 

出 版 物：《Journal of Semiconductors》 (半导体学报（英文版）)

年 卷 期：2021年第42卷第5期

页      面：85-90页

核心收录：

学科分类：08[工学] 0803[工学-光学工程] 

基　　金：supported by the National Natural Science Foundation of China (No. 61571235, 61871231) the Key Research&Development Plan of Jiangsu Province China(No. BE2019741) the Natural Science Foundation of Jiangsu Province China (No. BK20181390) 

主　　题：single-photon avalanche diode(SPAD) passive quenching&active recharging circuit(PQARC) analog counter nonlinearity 

摘      要：A compact pixel for single-photon detection in the analog domain is presented. The pixel integrates a single-photon avalanche diode(SPAD), a passive quenching & active recharging circuit(PQARC), and an analog counter for fast and accurate sensing and counting of photons. Fabricated in a standard 0.18 μm CMOS technology, the simulated and experimental results reveal that the dead time of the PQARC is about 8 ns and the maximum photon-counting rate can reach 125 Mcps(counting per second). The analog counter can achieve an 8-bit counting range with a voltage step of 6.9 mV. The differential nonlinearity(DNL) and integral nonlinearity(INL) of the analog counter are within the ± 0.6 and ± 1.2 LSB, respectively, indicating high linearity of photon counting. Due to its simple circuit structure and compact layout configuration, the total area occupation of the presented pixel is about 1500 μm^(2), leading to a high fill factor of 9.2%. The presented in-pixel front-end circuit is very suitable for the high-density array integration of SPAD sensors.