Combination of thermionic emission and tunneling mechanisms to analyze the leakage current for 4H-SiC Schottky barrier diodes

Abstract

A new method to analyze reverse characteristics of a 4H-SiC Schottky barrier diode has been presented in this paper. The model incorporates both the current induced by the tunneling of carriers through the Schottky barrier and that induced by the thermionic emission of carriers across the metal–semiconductor interface. The treatment includes the effect of image force, lowering both the thermionic emission and electron tunneling processes. This analysis allowed us to separate and identify the thermionic emission and tunneling components of the total current. The experimental reverse transition voltage between thermionic emission and tunneling process can be determined from the intersection of the two components by using two models: bias dependence and no bias dependence of barrier height. For high temperatures, the experimental reverse transition voltage increases with increasing temperature and decreases with increasing the doping concentration as predicted by Latreche’s model.