Neat Temporal Performance of InGaAs/InAlAs Single Photon Avalanche Diode with Stepwise Electric Field in Multiplication Layers

We have incorporated a novel design of stepwise electric field in the multiplication layers to the InGaAs/InAlAs single photon avalanche diodes (SPADs). The stepwise electric field profile aims to circumvent the dilemma between dark count rate, afterpulsing and temporal performance. SPADs with large ( $240~\mu \text{m}$ ) and small ( $25~\mu \text{m}$ ) active area are fabricated and characterized. The intrinsic temporal response for large and small SPADs has a full-width at half maximum of 72 and 67 ps respectively. Importantly, the diffusion tail exhibits only about 200 ps full-width at one-thousandth maximum, showing fast and neat temporal characteristics. Such devices also present reasonable dark count rate of $5\times 10^{6}$ Hz and $3\times 10^{7}$ Hz and moderate single photon detection efficiency of 32 % and 27 % at about 200 K respectively for large and small devices, manifesting that the avalanche build-up time can be improved without losing the detection performance using our specific design and optimized electric field distribution. Such improvement in temporal performance of SPADs should facilitate their capability in the applications of time-correlated single photon counting and light detection and ranging.