Analysis of C-face 4H-SiC MOS capacitors with ZrO_2 gate dielectric

摘要

ZrO_2 films were deposited on C-face 4H-SiC substrates by using an RF sputter at a temperature of 200°C. Then, ZrO_2 films were treated with RTA (rapid thermal annealing) process in Argon (Ar) and N_2 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 measurement temperature increases from room temperature (RT) to 150°C, the dielectric breakdown field reduces from 0.53 MV/cm to 0.41 MV/cm. The C-V curves shift to the left side as the measurement temperature increases from RT to 150°C. It also shows the existence of interface states at the deep level observed from the interface state ledge on C-V curves of capacitors at elevated measurement temperature.