High Temperature III-V Nitride RF Electronics

The III-V nitrides, (Al, In, Ga)N, are promising materials for high temperature, high power and high frequency devices due to the wide bandgaps, high electron saturation velocity and high electronic mobility transistor (HEMT) structures available in this alloy system. These devices would find wide-spread commercial use as power amplifiers in base station transmitters for personal communications an din military phased-array radar systems. A1GaN / GaN HEMTs on sapphire subtrates with promising DC and microwave characteristics have recently been demonstrated but further work is needed to develop devices suitable for high temperatures. The goal of this program is to develop AlGaN / GaN HEMTs capable of sustained high power operation. SiC substrates will be employed to improve heat spreading in the device and thermally stable silicides will be developed for the gate contact metallurgy. In Phase I, we will fabricate silicide Schottky contacts to AlGaN test structures and determine the effect of AlGaN composition, doping and surface damage on the barrier height. This thermally stable contact technology will be incorporated into AlGaN / GaN HEMTs in Phase II leading to the production of robust, high performance RF power devices.