CMOS SPAD Based on Photo-Carrier Diffusion Achieving PDP >40% From 440 to 580 nm at 4 V Excess Bias

A wide spectral response standard CMOS single-photon avalanche diode enabling simplified circuit interface for large array realization is reported. In this letter, the conventional p(+)-nwell junction photon detection probability (PDP) profile is enhanced utilizing photo-carrier diffusion processes, resulting in a considerable expansion of the sensitivity spectrum of more than 30%. The proposed device achieves PDP greater than 40% from 440 to 580 nm at a low excess bias, while the dark count rate is 16 Hz/mu m(2) and timing jitter (full-width at half-maximum) is 95 ps when using a 405-nm laser.