Lateral AlxGa1-xN power rectifiers with 9.7 kV reverse breakdown voltage

AlxGa1-xN (x=0-0.25) Schottky rectifiers were fabricated in a lateral geometry employing p(+)-implanted guard rings and rectifying contact overlap onto an SiO2 passivation layer. The reverse breakdown voltage (V-B) increased with the spacing between Schottky and ohmic metal contacts, reaching 9700 V for Al0.25Ga0.75N and 6350 V for GaN, respectively, for 100 mum gap spacing. Assuming lateral depletion, these values correspond to breakdown field strengths of less than or equal to9.67x10(5) V cm(-1), which is roughly a factor of 20 lower than the theoretical maximum in bulk GaN. The figure of merit (V-B)(2)/R-ON, where R-ON is the on-state resistance, was in the range 94-268 MW cm(-2) for all the devices. (C) 2001 American Institute of Physics.