Crosstalk-Free Single Photon Avalanche Photodiodes Located in a Shared Well

Advances in single photon avalanche detector (SPAD) arrays propose improving the fill factor by confining several SPADs in the same well, with a main issue related to crosstalk. In applications that measure at fixed times, the pixels can be inhibited before the arrival of the crosstalk charge. This letter reports the crosstalk characterization in an array of SPADs, where the sensors share the same n-well (fill factor 67%), and fabricated in a conventional CMOS technology. The reduction of the gating time completely eliminates the crosstalk, as predicted by the theory and TCAD simulations.