An SOI-Based SiGe Heterojunction Phototransistor with Large Operation Current Range

In this paper, the incident light distribution in device and photo-generated holes concentration of SOI-based and Si-based SiGe phototransistor (HPT) are simulated and analyzed. The parameters of the photocurrent gain, optical characteristic frequency, optical output characteristic curve and total capacitance change curve of two devices are compared. Compared with Si-based SiGe HPT, the maximal optical characteristic frequency and maximal optical gain of SOI-based SiGe HPT are increased by 24% and 49%. The kirk current density of SOI-based SiGe HPT for the maximal photo-charateristic frequency is 0.53 mA/um
²
, a 51% improvement than the value obtained from Si-based SiGe HPT.