SiGe/Si Heterojunction Internal Photoemission Separate Absorption and Multiplication Avalanche Middle Wavelength Infrared Photodiode

Abstract

Separate-absorption-and-multiplication (SAM) Avalanche PhotoDiode (APD) is widely accepted in optical communication systems due to the presence of large photocurrent gain. In this thesis, a designed SAM middle wavelength infrared avalanche photo detector operating at room temperature is presented. The designed photo detector is based on SiGe/Si heterojunction internal photoemission (HIP) and it is compatible with CMOS technology. The detection mechanism of the SiGe/Si HIP detector is infrared absorption in the degenerately doped p+-SiGe layer followed by internal photoemission of photoexcited holes over the heterojunction barrier. Silvaco TCAD tool is utilized to implement the simulation of this designed SiGe/Si HIP SAM APD. The structure of the designed APD is evaluated by simulation tools, the simulation results of the dark current, the current under illumination, photo-generation rate, recombination rate, and electrical field are shown in this thesis. The relation between dark current and generation-recombination is discussed at the end of this thesis.