BACKGATING EFFECTS IN GaAs FETs WITH A CHANNEL-SEMI-INSULATING SUBSTRATE BOUNDARY

Abstract

Several methods are presented to relate the backgating effects to hole traps near the channel-semi-insulating substrate interface of GaAs MESFETs. By analysis of the variation of the individual properties of the device the time dependence of backgating is shown to be related to the time constants of these traps and the temperature dependence of backgating is related to the temperature dependence of the emission from these traps. The current between the semi-insulating substrate and the channel is shown to be dominated by a generation mechanism rather than the Trap Fill Limited model. This means that a space charge region exists at the channel-substrate interface and the properties can be approximated to an n-p- junction.