Etch Pits of 4H-Silicon Carbide Surface Formed Using Chlorine Trifluoride Gas

摘要

Surface morphology ot a single-crystalline 4H-sihcon carbide (SiC) etched by chlorine trifluoride gas was studied over the wide temperature range of 570-1570 K at atmospheric pressure in a horizontal cold wall reactor. The etch rate of both the Si-face and C-face 4H-SiC at the substrate temperatures between 720 and 1570 K was simultaneously measured to be nearly flat at ca. 5 (un min~(-1). 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. This temperature-dependent behavior is expressed using the rate theory accounting for the slightly low activation energy at the spot causing the pit. The etch pits formed at low temperature may have relationship with crystalline defects, such as threading edge dislocation and screw dislocation.