Temperature Dependence of 4H-SiC JBS and Schottky Diodes after High Temperature Treatment of Contact Metal

摘要

In this work we demonstrate performant characteristics of 1.2KV Schottky, Junction Barrier Schottky (JBS) and implanted PN diodes processed on the same 4H-SiC wafer. A bi-layer Ni/Ti scheme for the contact metallisation submitted to high temperature rapid thermal anneals is proved to form good ohmic contact on p~+ implanted areas while maintaining good Schottky characteristics on lightly doped n-type regions. I-V characteristics have been evaluated from room temperature up to 560K. At room temperature, Schottky diodes have slightly better specific on-resistance, but when working temperature is increased, the JBS diode exhibits better characteristics due to the temperature dependent activation of bipolar current injection from the p~+ grid. From reverse measurements, the JBS diodes showed lower leakage current and higher breakdown voltages in comparison to that of the Schottky diodes in the whole range of temperatures.