Improvement of Threshold Voltage Reliability of 4H-SiC MOSFETs With Lanthanum Silicate by High Temperature Forming Gas Anneal

Abstract

We report the effect of a high-temperature forming gas anneal (FGA) on the electrical characteristics and threshold voltage (VT) instability of high-mobility Si-face (0001) 4H-SiC metal oxide semiconductor field effect transistors (MOSFETs) with lanthanum silicate (LaSiOx). The MOSFET with LaSiOx after 800 °C FGA in 5% H2 and 95% N2 mixture shows significantly reduced VT shift under 3-MV/cm positive bias stressing from 2.78 to 1.65 V, while maintaining high field-effect mobility of 122.7 cm2/Vs and sufficiently positive VT of 2.76 V.