An improved two-dimensional simulation model (MEGA) for GaAs MESFET applicable to LSI design

摘要

The authors have developed a two-dimensional device simulator for GaAs MESFETs, based on the drift-diffusion current equation in which the actual device structure, including an ion-implanted layer, n/sup +/ source and drain geometry, and substrate with very low impurity concentration, is taken into account. The electron mobility is assumed to be a function of the electric field component parallel to the gradient of the quasi-Fermi level. This mobility model eliminates the discrepancy in the conventional absolute-field-value-dependent mobility model, which seriously underestimates the drain current. The calculated results show good agreement with experimental results, even for a device with submicron (0.7- mu m) gate length. This confirms the effectiveness of using the present device simulator in the practical design of GaAs MESFET LSIs.