Implementation of lateral Ge-on-Si heterojunction photodetectors via rapid melt growth and self-aligned microbonding for Si photonics

Abstract

Heterogeneous integration of Ge on a Si lateral p-i-n junction by rapid melt-growth method and self-aligned microbonding is presented. A very thin Ge (100 nm) strip butt-coupled to a Si waveguide for implementing a waveguide photodetector is reported with a low dark current of 1 nA at -3 V bias. The measured 3 dB cut off frequency for the photodetectors is 30 GHz. The internal device responsivity is estimated to be 0.72 A W-1 at the reverse bias of 3 V.