Numerical Simulation of GaAs/AlGaAs Heterojunctions Including Interface States and Thermionic Emission

Abstract

The authors present a simple formulation to include interface states within the numerical modelling of abrupt heterojunction. In this formulation, the interface states are included in Poisson's equation by expressing the electric potential at the interface as a function of those at the neighbouring mesh points using the boundary condition of the electric displacement. The importance of the interface states on the I-V characteristics is demonstrated through the simulation of n-N and p-N GaAs⁄AlGaAs abrupt hetero junctions. The interface states are found to affect the I-V characteristics through the change in the barrier resulting from the sheet of charge at the interface. The effect of donor-and acceptor-like states is also investigated. Results show that the acceptor states have stronger impact on the characteristics of isotype heterojunction and the donor states have relatively more effect on the anisotype hetero junction.