High Power AlN/AlGaN/GaN Recessed Gate Heterostructure Field Effect Transistor

We propose to develop a new approach to recessed gate/active passivation AlGaN/GaN FET technology for the development of high-power AlN/AlGaN/GaN recessed gate Heterostructure Field Effect Transistors (HFET) for microwave amplifiers. We will use ourproprietary technology of the textured AlN thin film epitaxy by metal organic chemical vapor deposition (MOCVD) on AlGaN or AlN. The etching rate of this material is at least two orders of magnitude higher that the etching rate of our regular AlN or AlGaNlayer that can serve as an etch stop layer. Our preliminary capacitance voltage measurements demonstrate the increased sheet carrier densities and good pinch-off characteristics in the structures with such textured AlN layer. The thin textured AlN film canbe easily wet etched by diluted KOH. The etching rate and etching pattern can be well controlled. Silicon nitride passivation will be used to prevent AlN oxidation. Our approach will help to increase the power levels and decrease the size microwave power amplifiers, which is a key for the Transmit/Receive (T/R) module.