A study on the reactive ion etching of SiC single crystals using inductively coupled plasma of SF6-based gas mixtures

Inductively coupled plasma reactive ion etching (ICP-RIE) of SiC single crystals using SF6-based gas mixtures was investigated. Mesas with smooth surfaces with vertical sidewalls were obtained, with an etch rate of about 360 nm/min, roughness of about 0.8 nm, and verticality of 85° at optimum conditions. Efforts to increase the etch rate by increasing bias power resulted in a trenching effect. Sloped sidewalls (about 50°) could be obtained by performing RIE (without ICP power) with a photoresist or SiO2 etch mask. Results of various surface characterizations and I-V measurements using an Au Schottky barrier diodes indicated little contamination and/or damage on the etched SiC surfaces.