CHARGE-COLLECTION CHARACTERISTICS OF GAAS-MESFETS FABRICATED WITH A LOW-TEMPERATURE-GROWN GAAS BUFFER LAYER - COMPUTER-SIMULATION

Two-dimensional device simulations of GaAs MESFETs fabricated with a l aw-temperature grown GaAs (LT GaAs) buffer layer reveal a sensitive de pendence of the charge-collection characteristics on various structura l and operational parameters. Simulations performed for above-band-gap pursed laser excitation indicate that, even when the bulk of the char ge is deposited above the LT region, the improved SEU and charge-colle ction performance of LT GaAs devices largely is a consequence of the r educed efficiency of the carrier-induced charge-enhancement (gain) mec hanisms.