4H-SiC Wafer Surfaces Irradiated with Femtosecond Laser at Fluence below the LSFL Threshold

This study investigates the microstructural and surface compositional changes of 4H-SiC wafers irradiated with femtosecond lasers at fluences below the threshold for low-spatial frequency laser-induced periodic surface structures (LSFL). Using scanning electron microscopy, cross-sectional transmission electron microscopy, and X-ray photoelectron spectroscopy, we characterized the processed SiC surfaces. Our results demonstrate precise control over the oxide layer thickness on the SiC surface at low laser fluences, allowing for the removal of only a few nanometers. This precise modification holds potential for future applications in wafer bonding by enabling the creation of a shallow SiO2 layer on the SiC surface.