A single photon avalanche diode in standard CMOS technology for range finding

We design a single photon avalanche diode (SPAD) in a standard 180-nm CMOS technology. The SPAD consists of a P+/n-well junction with octagon shape, a p-well guard-ring and a ploy guard-ring. The two rings prevent SPAD from premature edge breakdown events and STI interface trap influence, respectively. The measurement results show that a typical dark count rate of SPAD is 8 kHz at room temperature and its PDP is 8% at wavelength of 640nm. The distance measurement is carried out by a SPAD direct Time of Flight method. A centimeter-level precision is achieved based on time-correlated single-photon counting technology.