Impact of interface traps on current-voltage characteristics of 4H-SiC Schottky-barrier diodes

摘要

This paper presents a physical model based on interface traps to explain both the larger barrier heights of practical Schottky diodes in comparison to the theoretically expected values and the appearance of a knee in the log I-V characteristics. According to this model, acceptor-type interface traps near the valance band increase the Schottky barrier height, which shifts the log I-V characteristic to higher forward-bias voltages. In addition to the acceptor traps, donor-type interface traps can appear near the conduction band, and when they do, they cause the knee in the log I-V characteristics as their energy level falls below the Fermi level and the charge associated with these traps changes from positive to neutral.