256×256, 100kfps, 61% Fill-factor time-resolved SPAD image sensor for microscopy applications

Abstract

A 256×256 Single Photon Avalanche Diode (SPAD) image sensor operating at 100kfps with fill factor of 61% and pixel pitch of 16μm is reported. An all-NMOS 7T pixel allows high uniformity gated operation down to 4ns and ∼600ps fall time with on-chip delay generation. The sensor operates with 0.996 temporal aperture ratio (TAR) in rolling shutter and has a parasitic light sensitivity (PLS) in excess of −160dB when operated in global shutter. Gating and cooling allow the suppression of dark noise, which, in combination with the high fill factor, enables competitive low-light performance with electron multiplying CCDs (EMCCDs) whilst offering time-resolved imaging modes.