NH_3 Plasma Pretreatment of 4H-SiC(0001) Surface for Reduction of Interface States in Metal-Oxide-Semiconductor Devices

摘要

We have investigated NH_3 plasma pretreatment and SiON deposition for the C face of 4H-silicon carbide (4H-SiC) and characterized interface properties. It is revealed that the NH_3 plasma pretreatment effectively reduces interface state density and increases field-effect mobility on the C face of 4H-SiC. Both nitrogen and hydrogen passivate interface traps, resulting in improved electron channel mobility. Although the threshold voltage was high due to electron traps in the SiON deposition layer, the nitrided layer formed by NH_3 plasma pretreatment suppressed the influence of coulomb scattering of the trapped electrons in the deposited SiON layer, leading to increased field-effect mobility.