Dry Polishing of Non-Cubic Crystal Wafers

We have investigated polishing non-cubic crystal wafers using a unique dry polishing process. The wafers tested were GaN and SiC. Wafers of both GaN and SiC have surfaces terminated by different materials. Each of these surfaces will react differently when polished. For GaN the Ga (000–1) surface has a higher degree of chemical inertness than the nitrogen terminated surface (0001). To compensate for this difference in chemical inertness complex slurries and long polish times are used in chemo-mechanical polishing (CMP). Dry polishing equaled the surface finish and removal of subsurface damage of CMP in significantly reduced polishing times.