(Al/sub x/Ga/sub 1-x/)/sub 0.5/In/sub 0.5/P/In/sub 0.15/Ga/sub 0.85/As (x=0, 0. 3, 1. 0) heterostructure doped-channel FETs for microwave power applications

The quaternary (Al/sub x/Ga/sub 1-x/)/sub 0.5/In/sub 0.5/P (0/spl les//spl times//spl les/1) compounds on GaAs substrates are important materials used as a Schottky layer in microwave devices. In this report, we systematically investigated the electrical properties of quaternary (Al/sub x/Ga/sub 1-x/)/sub 0.5/In/sub 0.5/P materials and concluded that the best composition for improving the device performance is by substituting 30% (x=0.3) of Ga atoms for Al atoms in GaInP material. The Schottky barrier heights (/spl phi/B) of (Al/sub x/Ga/sub 1-x/)/sub 0.5/In/sub 0.5/P layers were 0.85/spl sim/1.00 eV. We successfully realized the (Al/sub x/Ga/sub 1-x/)/sub 0.5/In/sub 0.5/P/In/sub 0.15/Ga/sub 0.85/As (x=0, 0.3, 1.0) doped-channel FETs (DCFETs) and demonstrated excellent dc, microwave, and power characteristics.