Investigation of electron-hole generation in MOS capacitors on 4H SiC

This paper investigates electron-hole generation in n-type MOS capacitors on 4H-SiC with the gate oxide directly grown in either 100% NO or 10% N₂O. High-temperature capacitance-transient measurements were used to determine and compare the contributions of carrier generation in the bulk and at the SiO₂-SiC interface. The effective generation rate in the bulk is similar in the MOS capacitors with either type of gate oxide, whereas the effective surface-generation rate is much lower in the case of oxides grown in 100% NO. Moreover, the effective surface-generation rate in these oxides is reduced to the level that is comparable to the effective bulk-generation rate. This result demonstrates the high quality of MOS capacitors with the gate oxide directly grown in 100% NO.