The GaAs MESFET is designed, fabricated and measured. The GaAs MESFET which has $I_{DSS}$ Is 210mA and $V_{DS}$ is 4.5V on condition that single finger gate width is 150μm and gate width is 900μm and gate to gate distance is 40μm and substrate thickness is 200μm is fabricated.
On the one hand, the value of $g_{m,ext}$ is recorded approximately 80 mS/mm at the gate length is 2 μm by the three layer P.R. process using 5:1 projection lithography system.
A GaAs MESFET fabricated by LPE, MOCVD and VPE wafer is compared and D.C., r.f. and reliability measurement method is discussed and measured data are presented.