An optimized TCAD simulation of a low-power, high-frequency lateral SiGe HBT on SOI device

Abstract

This work refines the simulation parameters and physical models for a nano-scale lateral SiGe Heterojunction Bipolar Transistor on Silicon-on-Insulator. The goal of this paper is to accurately model the electrical and thermal characteristics of the device. The necessary models for carrier mobility degradation and thermodynamic modeling are introduced into the simulation environment. Examination of the electron velocity, mobility, and temperature distribution profiles within the base of the device provides the information needed to adjust the parameters of the Hydrodynamic and electron Energy-Balance equations to eliminate non-physical results such as spurious velocity overshoot and negative differential resistance in the output characteristics. From these refined simulations, accurate common-emitter output, Gummel plots, cutoff frequency and maximum oscillation frequency as functions of collector current are obtained and plotted. The simulation refinement methodology outlined in this paper lays the necessary groundwork for investigation of future structural refinements to the device as well as developing accurate circuit models for the device.