| This thesis presents work on two significant design areas which improve the performance of single photon avalanche photodiodes (SPAD) for near-infrared detection. The first is a replacement for conventional zinc diffusion patterns, in which the field crowding effect of the junction is purposely utilized throughout the device. This design intends to address the practical non-uniformities that arises with device fabrication. Measurement results show >10x improvement in single photon detection efficiency (SPDE) while the dark count rate (DCR) is reduced by >10x, when compared to single diffused wells.;The second is on a self-quenching epitaxial design, created through the use of a heterojunction energy barrier. Self-quenching removes the need for external quenching circuits, allowing for simpler manufacturing of large imaging arrays, faster timing performance, and higher efficiencies. Results from modeling, fabrication, and experimental measurements of these devices are discussed.;In particular, the dependence of the recovery time and afterpulsing rate on the device design and operating conditions are extensively examined experimentally. Implications of these effects, along with the SPDE, total DCR, and timing jitter of the device are predicted using a Monte Carlo model. |
