Description and Verification of the Fundamental Current Mechanisms in Silicon Carbide Schottky Barrier Diodes

Abstract

Attempts to model the current through Schottky barrier diodes using the two fundamental mechanisms of thermionic emission and tunnelling are adversely impacted by defects and second order effects. This has led to the publication of countless different models to account for these effects, including some with non-physical parameters. Recently, we have developed silicon carbide Schottky barrier diodes that do not suffer from second order effects, such as excessive leakage, carrier generation and recombination, and non-uniform barrier height. In this paper, we derive the foundational current equations to establish clear links between the fundamental current mechanisms and the governing parameters. Comparing these equations with measured current–voltage characteristics, we show that the fundamental equations for tunnelling and thermionic emission can accurately model 4H silicon carbide Schottky barrier diodes over a large temperature and voltage range. Based on the obtained results, we discuss implications and misconceptions regarding barrier inhomogeneity, barrier height measurement, and reverse-bias temperature dependencies.