Tunneling in submicron CMOS single photon avalanche diodes

Tunneling is studied in two main single-photon avalanche diode (SPAD) topologies, which are n-tub guard ring (NTGR) and p-tub guard ring (PTGR). Device simulation, I-V measurements, and dark count calculations and measurements demonstrate that tunneling is the main source of noise in NTGR, but it is