A 256 x 256, 100-kfps, 61% Fill-Factor SPAD Image Sensor for Time-Resolved Microscopy Applications

A 256 x 256 single-photon avalanche diode image sensor operating at 100 kfps with fill factor of 61% and pixel pitch of 16 mu m is reported. An all-nMOS 7T pixel allows gated operation down to 4 ns and similar to 600-ps fall time with on-chip delay generation. The sensor operates with 0.996 temporal aperture ratio in rolling shutter. Gating and cooling allow the suppression of dark noise, which, in combination with the high fill factor, enables competitive low-light performance with electronmultiplying charge-coupled devices while offering time-resolved imaging modes.