Design of a High-Hole-Mobility Ge Transistor for Si-Driven Heterogeneous Integrated Circuits

Abstract

A high-hole-mobility transistor (HHMT) with an intrinsic Ge channel is optimally designed and its DC and high-frequency performances are investigated by technology computer-aided design (TCAD) simulation. An HHMT with a Ge channel and AlGaAs barrier on the Si substrate is characterized with a particular interest in the barrier design. More specifically, barrier doping concentration, total barrier thickness, and high-doped barrier thickness are considered as the critical design variables. A permissibly optimized device demonstrates cut-off frequency (fT) of 20 GHz and maximum oscillation frequency (fmax) of 80 GHz at a channel length of 90 nm. The Ge HHMT with an AlGaAs barrier has the potential to be a component in the heterogeneously integrated monolithic circuits made of Si, group-IV alloys, and III-V compound semiconductors where electronic and optical devices can be simultaneously integrated with enhanced device performances.