Papers by Author: Keiko Tanaka

Abstract: Selective etching on the surface of single-crystalline 4H-SiC was performed using ClF3 gas at 700 K and at atmospheric pressure in a cold wall reactor. The etch pits at the Si-face and C-face 4H-SiC surface may have relationship with the threading edge and screw dislocation.

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.

Abstract: The etching technology for 4H-silicon carbide (SiC) was studied using ClF3 gas at 673-973K, 100 % and atmospheric pressure in a horizontal reactor. The etch rate, greater than 10 um/min, can be obtained for both the C-face and Si-face at substrate temperatures higher than 723 K. The etch rate increases with the increasing ClF3 gas flow rate. The etch rate of the Si-face is smaller than that of the C-face. The etched surface of the Si-face shows many hexagonal-shaped etch pits. The C-face after the etching is very smooth with a very small number of round shaped shallow pits. The average roughness of the etched surface tends to be small at the higher temperatures.