High fill factor digital Silicon Photomultiplier structures in 130nm CMOS imaging technology

This paper discusses recent progress in the realization of fully digital Silicon Photomultipliers (SiPMs) in an advanced 130nm CMOS imaging process. A dedicated electrical/optical crosstalk characterization chip is reported, featuring a 16×16 SPAD SiPM with on-chip quench, SPAD enable/disable and readout circuitry positioned outside the SPAD array. Recent advances in well sharing are employed to deliver a fill factor of 38%. Integral crosstalk of <;2% was measured between a SPAD and its neighbors - the lowest yet reported for a high fill factor SiPM structure - measured using parallel readout channels allowing adjacent SPAD waveforms to be monitored in real time.