Improvement of interface properties in SiC(0001) MOS structures by plasma nitridation of SiC surface followed by SiO2deposition and CO2annealing

Abstract

Although nitridation passivates defects at the SiO2/SiC interface, avoiding the introduction of nitrogen atoms into SiO2 is crucial for reliability. This paper presents a method to selectively introduce nitrogen at the SiC-side of the interface. The method comprises the following steps: (i) plasma nitridation of the SiC surface, (ii) sputter deposition of SiO2, and (iii) annealing in a CO2 ambient. Significantly low D it values of about 1 × 1011 cm-2eV-1 were obtained near the conduction band edge of SiC. Furthermore, the resulting interface properties were hardly degraded by excimer ultraviolet light irradiation, indicating better stability compared with a NO-nitrided sample.