Progress and Challenges of AlGaN Schottky Diodes Grown on AlN Substrates

Quasi-vertical, high Al composition AlGaN Schottky diodes with breakdown voltages up to 500 V were grown on high quality AlN single crystal substrates. Diodes exhibited a similar to 10(6) current rectification ratio, a 7 MV/cm peak field at blocking, and a 1.45 MW/cm(2) unipolar figure of merit. Challenges for this emerging technology, including doping limitations and compensation in AlGaN alloys, Ohmic contacts, and device termination are discussed.