Perimeter-Gated Single-Photon Avalanche Diode Imager with Vanishing Room Temperature Dark Count Probability

We report on a perimeter-gated single-photon avalanche diode (pg-SPAD) imager fabricated in a $0.35\ \mu m$ CMOS process. The imager had 4,096 pixels disposed in a two-dimensional array ( $64\times 64$ ) and peripheral circuitry for pixel access and readout. We demonstrate that the room temperature probability of a dark count occurring at a single pixel vanishes when perimeter gating is used. We further demonstrate that the array-wide noise variance decreases with an increase in perimeter gate voltage magnitude. The proposed imager architecture lays the foundation for single-photon imaging with negligible dark signal non-uniformity (DSNU).