Impact of post-deposition annealing on SiO2/SiC interfaces formed by plasma nitridation of the SiC surface and SiO2 deposition

We examined the impact of post-deposition annealing (PDA) on SiO2/SiC structures formed by plasma nitridation of the SiC surface followed by sputter deposition of SiO2. The interface state density near the conduction band edge of SiC was reduced from about 2 x 10(12) to 1 x 10(11) eV(-1) cm(-2) as the CO2-PDA temperature increased from 1050 degrees C to 1250 degrees C. In addition, the sample treated by CO2-PDA exhibited substantially higher immunity against positive gate bias stress than the standard NO nitridation. Our findings indicate that defect passivation by CO2-PDA plays a crucial role in improving the performance and reliability of SiC MOS devices formed by sputter-SiO2 deposition.