Analysis of C-Face 4H-SiC MOS Capacitors with ZrO2 Gate Dielectric

ZrO2 films were deposited on C-face 4H-SiC substrates by using an RF sputter at a temperature of 200°C. Then, ZrO2 films were treated with RTA (rapid thermal annealing) process in Argon (Ar) ambient at 600°C, 700°C and 800°C for 4 minutes, respectively. The samples with RTA process show the lower leakage currents. As the measure temperature increases from room temperature (RT) to 150°C, the dielectric breakdown voltage reduces from 3 V to 1 V. The difference between quasi C-V characteristics and high frequency C-V characteristics at 1 MHz becomes larger with increasing RTA temperature. The C-V curves also shift to the left side as the measure temperature increases from RT to 150°C. It also shows the ledge on the C-V curves of samples with RTA at elevated measure temperature.