Electrical characteristics of bulk GaN-based Schottky rectifiers with ultrafast reverse recovery

A vertical Schottky diode rectifier was fabricated using a bulk n-GaN wafer. Pt Schottky contacts were prepared on the Ga face and full backside ohmic contact was prepared on the N face by using Ti/Al. The root mean square surface roughnesses of the Ga and N faces are 0.61 and 4.7 nm, respectively. A relatively high breakdown field of 5.46 kV/cm was achieved with no additional edge termination. The breakdown field decreases as the size of the device increases. The background electron concentration of the bulk GaN wafer was low (5x10(15) cm(-3)), which may lead to a relatively high breakdown field even with no special edge termination. The forward turn-on voltage was as low as 2.4 V at the current density of 100 A/cm(2). The device exhibited an ultrafast reverse recovery characteristics (reverse recovery time < 20 ns). (c) 2006 American Institute of Physics.