Atomically controlled surfacing of single crystalline SiC and GaN by catalyst-referred etching

A novel abrasive-free planarization method named catalyst-referred etching (CARE) was developed. In this method, a polishing pad coated by a catalytic material is used. During the processing, topmost areas of the work substrate, which contacts most frequently with the catalytic material, are preferentially etched off through the catalytically induced chemical reaction. This paper reviews the CARE method from the viewpoints of the equipment configuration and applicability to single crystalline 4H-SiC and GaN substrates and reports that an atomically well-ordered surface with a step-and-terrace structure was observed over the whole area of the 2 inch substrate. The height of the step was a single bilayer. In addition, The CARE was applied to oxidized materials of ZnO and sapphire and can also smoothen the surfaces to be the similar to those of 4H-SiC and GaN substrates.