Controlled low Si doping and high breakdown voltages in GaN on sapphire grown by MOCVD

Abstract

Controlled n-type doping down to 2 × 1015 cm−3 was achieved in GaN grown on sapphire by MOCVD by balancing the n-type Si doping with respect to the background carbon and oxygen levels. A dopant level of ∼1 × 1016 cm−3 displayed a very high mobility of 899 cm2 V−1 s−1. High electron mobility in the drift layer leads to a low on resistance and high current densities without compromising on any other properties of the device. Schottky diodes processed on these low n-type layers showed low Ron values, while the p–n diodes display high reverse breakdown voltages in excess of 1000 V for 8 μm thick drift layers with a doping of 2 × 1015 cm−3.