Single-photon avalanche photodiodes (SPADs) based on an improved structure were fabricated. Measurement
results show that SPADs with a sharp rising I-V and gain curves were obtained by controlling SPAD's
multiplication region thickness. The tunneling leakage current was reduced. Device's dark count rates (DCR) and
single photon detection efficiency (SPDE) were measured using our innovative gated current bias scheme under
different operating conditions to obtain a maximum SPDE. The experimental data demonstrated that SPADs'
performance can be improved by decreasing the difference between the breakdown voltage and the punch through