Simulated study on the InP/InGaAs DHBT under proton irradiation**Project supported by the National Basic Research Program of China (No. 2010CB327505), Advance Research project of China (No. 51308xxxx06), and Advance Research Foundation of China (No. 9140A08xxxx11DZ111).

Abstract

A 3D model simulation of InP/InGaAs/InP DHBT is reported in this paper. A comprehensive set of built-in physical models are described, including Stratton's hydrodynamic model, high-fields mobility model and thermionic emission model. A mixed-mode environment is required for AC simulation instead of simulating an isolated HBT, in which the HBT is embedded in an external circuit, and the circuit voltage and current equations are solved along with the Poisson equation and transport equations. In AC simulation, simulator Sentaurus provides the computation of the small signal admittance Y matrix. From the results of Y matrix, the small signal equivalent circuit is constructed with the conductance and capacitance obtained from Y matrix, and the AC parameters, such as S-parameters, will be calculated. The small signal AC characteristics of InP/InGaAs DHBTs under proton irradiation are simulated with different fluences of proton irradiation. Simulation results show that the maximum oscillation frequency will be degraded when fluence of proton irradiation is increased.