Precise microfabrication of wide band gap semiconductors (SiC and GaN) by VUV–UV multiwavelength laser ablation

Abstract

High-quality deep etching of single crystal 6H-SiC substrate and epitaxial GaN thin film by 266-nm laser ablation coupled with a vacuum ultraviolet (VUV) Raman laser (133–184 nm), followed by chemical treatment in HF for SiC and HCl solution for GaN is demonstrated. The etch rate was as high as 35 nm pulse −1 for SiC and 55 nm pulse −1 for GaN. Scanning probe microscopy measurement indicates that the surface of the etched films was structurally well defined and cleanly patterned. Micro-Raman measurement of ablated SiC samples, and micro-photoluminescence measurement of ablated GaN samples revealed no severe damage to the optical properties or the crystal structure. The mechanism of the VUV-266 nm laser ablation of SiC and GaN is discussed based on the band structure.