Ge-si Separate Absorption And Multiplication Avalanche Photodiode For Geiger Mode Single Photon Detection

摘要

A Ge-Si separate absorption and multiplication avalanche photodiode (SAM-APD) is reported. The structure is grown using a low temperature in situ clean and epitaxy process, T_(in situ) and T_(epitaxy) < ～460 ℃, resulting in a Ge layer with a dislocation density of ～5 × 10~(10) cm~(-2). The SAM-APD has a responsivity of 3.2 × 10~(-4) A/W (1310 nm) and a dark current density at punch-through of 0.2 mA/cm~2. In Geiger mode (GM) at 206 K, the dark count rates (DCRs) are ～280 kHz, which is within an order of magnitude of DCR reported for InGaAs/InP GM APDs despite the high defect density in the Ge.