4H-SiC Surface Morphology Etched Using ClF3 Gas

Abstract

The morphology of a single-crystalline 4H-silicon carbide (SiC) substrate surface after etching by chlorine trifluoride (ClF3) gas was studied over the wide temperature range of 673-1573 K at atmospheric pressure in a horizontal cold wall reactor. The Si-face and C-face showed pitted surfaces at low temperatures; the pits tended to become small and shallow with the increasing substrate temperature. The etching for 0.5 min at the substrate temperature of 1573K and at the ClF3 gas concentration of 1% could maintain a specular surface on both the Si-face and C-face 4H-SiC, the root-mean-square roughness of which was comparable to that of the substrate before etching.