Buried-Channel GaAs MESFETs with Improved Small-Signal Characteristics

Abstract

Buried-channel GaAs MESFETs with quarter micron gate lengths have been fabricated by ion implantation into undoped LEC material. Compared to conventional half and one micron MESFETs, these devices exhibit higher gain, wider bandwidth, reduced short channel effects, and much less dispersion and frequency dependence of the small-signal parameter values. These improvements are obtained because the carrier trapping at the channel-substrate and channel-surface interfaces, common in a conventional MESFET, is considerably reduced in the buried-channel MESFET by the presence of the implanted p-type layers. Improved small-signal device characteristics will likely expand the range of applications for GaAs MESFET technology into precision analog and mixed analog-digital subsystems not currently exploited by GaAs.