In-situ cleaning of 4H-SiC (0001) surfaces by using pulsed laser irradiation

The 4H-SJC (0001) surfaces before and after pulsed laser cleaning (PLC) have been investigated by I-V, C-V, and time-of-flight (TOP) measurements. The electrical characteristics for metal/4H-SiC structures were improved by PLC at the laser energy density of 30 mJ/cm². The ideality factor and the pinning degree for metal/4H-SiC structures decreased by using PLC at 30 mJ/cm² prior to metallization. TOP measurements indicate that atoms on 4H-SiC surfaces are desorbed by pulsed laser irradiation above 30mJ/cm². We found that pulsed laser irradiation at 50mJ/cm² causes decomposition of 4H-SiC surfaces. We discuss the laser energy density dependence of PLC of 4H-SiC (0001) surfaces.