Simulation of electric field distribution in CMOS single photon avalanche diodes at breakdown voltage

Abstract

We simulate the electric field distribution in single-photon avalanche diodes (SPADs) fabricated by CMOS 0.25-μm high-voltage technology to explain the observed non-uniform 2-D photo-count mapping. The cause of non-uniform electric field distribution at the breakdown voltage is discussed with the aid of simulation. A method for improving the electric field uniformity is also proposed accordingly.