In-Situ Cleaning of 4H-SiC (0001) Surfaces by Using Pulsed Laser Irradiation

The 4H-SiC (0001) surfaces before and after pulsed laser cleaning (PLC) have been investigated by I-V, C-V, and time-of-flight (TOF) 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. TOF measurements indicate that atoms on 4H-SiC surfaces are desorbed by pulsed laser irradiation above 30 mJ/cm2. Authors found that pulsed laser irradiation at 50 mJ/cm2 causes decomposition of 4H-SiC surfaces. Authors discuss the laser energy density dependence of PLC of 4H-SiC (0001) surfaces. 11 refs.