Channel-substrate current and breakdown characteristics in GaAs MESFETs with varied MBE buffer thickness

This paper presents a careful and detailed study of the electrical and reliability characterizations on MBE-grown GaAs MMIC MESFETs with an undoped GaAs buffer layer of thickness of 300 and 500 nm upon the semi-insulating (SI) GaAs substrate. The test vehicle was a discrete MESFET transistor from the RFPCM. It is a two-gate-finger recessed-gate MESFET with a gate length of 0.8 /spl mu/m and a total width of 460 /spl mu/m (230 /spl mu/m each finger). The gate materials are Ti/Pd/Au, and the n-channel has a thickness of /spl sim/1/4 /spl mu/m with a carrier concentration of /spl sim/10/sup 7//cm/sup 3/.