Effect of contact geometry on 4H-SiC rectifiers with junction termination extension

Abstract

SiC rectifiers with an on/off current ratio of 4×10 5 (at 1.5 V/−500 V) were fabricated using junction termination extension (JTE) and dielectric overlap. The reverse breakdown voltage was inversely dependent on contact area and was not a strong function of JTE length up to 40 μm. Similarly, for a given JTE length, the metal overlap did not have a strong influence on breakdown voltage. Oval- and circular-shaped contacts produced larger breakdown voltages than square rectifying contacts. The on-state resistance, R ON, was 4.2 m Ω cm 2, which is close to the theoretical minimum of these rectifiers using Ni Schottky contacts. The figure-of-merit ( V B) 2/ R ON was as high as 156 MW cm −2.