Optimization of Schottky-contact process on 4H-SiC Junction Barrier Schottky (JBS) Diodes

Abstract

SiC Junction Barrier Schottky (JBS) Rectifier is a kind of unipolar power diode with low threshold voltage and high reverse blocking voltage. And the Schottky barrier φBN is a main technology parameter, which could greatly affect the forward conduction power and reverse leakage current in the JBS rectifiers. Therefore, it is necessary to balance the influence of φBN on the electrical characteristics of JBS rectifiers. In this paper, physical properties at the metal-semiconductor at the Schottkycontact could be optimized by the improvement of Schottky-contact process. And this optimization could significantly decrease φBN to reduce the on-state voltage drop VF and minimize negative impact on its reverse characteristics. After the completion of Silicon carbide JBS diodes, the static parameter electrical test was carried out on the wafer by using Keysight B1505A Power Device Analyzer/Curve Tracer. The test results show that the Schottky barrier height φBN of JBS Schottky rectifier manufactured by the modified Schottky foundation technology decreased from 1.19eV to 0.99eV and IR increased from 1.08μA to 3.73μA (reverse blocking voltage VR=1200V). It indicated that the power consumption of Schottky barrier junction in JBS rectifiers could be significantly reduced by about 25%, and IR could effectively be limited to less than 10μA.