Impact of High-Temperature Storage Stressing (HTSS) on Degradation of High-Voltage 4H-SiC Junction Barrier Schottky Diodes

摘要

High-temperature storage stressing (HTSS) experiments were carried out on high-voltage 4H-SiC junction barrier Schottky (JBS) diodes. The effects of the high-temperature (up to 275 °C) storage under air environment on thermal stability of the 4H-SiC JBS are investigated. The electrical parameter shifts for tested diodes after the HTSS were investigated in detail, and related degradation mechanisms have been discussed. It is found that HTSS has no effect on the Schottky barrier height, the ideality factor (n), and specific on-resistance (R_on-sp). However, it was interesting that the breakdown voltage (VBR) of the devices was decreased first and then increased as the storage time increased. With the analysis of the SiO₂/4H-SiC interface characteristics using metal-oxide-semiconductor structure fabricated simultaneously with the investigated 4H-SiC JBS on the same wafer and technical computer-aided design (T-CAD) simulations, trapped-electrons and holes located at the interface of SiO₂/4H-SiC on termination region are identified to be the basic reason causing the degradation of reverse characteristics in the devices.