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

摘要

SiC rectifiers with an on/off current ratio of 4 x 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 mΩcm~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).