Robust Simulation Of GaAs Devices Using Energy Transport Model

Abstract

The carrier transport mechanism in GaAs which includes a negative different mobility in the carrier velocityfield curve when implemented in the 2D device simulator, causes grid-dependent numerical instability and poor convergence behavior. It has well been established in the literature [I, 27 that the conventional drift-diffusion (DD) approximation which assumes a local thermal equilibrium among the same type of carriers (electrons or holes) has significant shortcomings in the description of GaAs device operation. In this paper we report an extension of the energy transport (ET) model [3,4] in which carrier energy conservation equations are solved to GaAs device simulation. A technique whereby the empirical form of the field-dependent mobility is transformed to an energy-dependent one used in the ET model is presented. The empirical formula describing the dependence of mobility on electric field implemented in the 2D device simulator PISCES [6] has the form ~ ( N T , E) = p 0 ( N T ) + y ( ’ 0 ) 4 1+(e14 , where p, is the low-field mobility, E is the