Ge/Si heterojunction photodetector for 1.064 µm laser pulses

Abstract

Isotype and anisotype heterojunction Ge/Si photodetectors have been made by depositing Ge layer onto monocrystalline Si using vacuum evaporation technique. These detectors before and after annealing were utilized to detect 1.064 µm Nd:YAG laser pulses. The study also includes determination of the optimum Ge thickness and annealing conditions. The experimental results show that the photoresponse highly improve after classical thermal annealing (CTA) and rapid thermal annealing (RTA).The voltage responsivity and rise time results are strongly dependent on annealing type and conditions. It is found that the optimum conditions can be obtained for n-Ge/p-Si photodetector prepared with 200 nm Ge thick and annealed with RTA at 500°C/25 sec.