SBIR Phase I: Gentle Atomic Level Chemical Mechanical Smoothening (CMS) of GaN and SiC Substrates

This Small Business Innovation Research (SBIR) Phase I research project will develop a novel gentle atomic scale surface polishing method for GaN and SiC based wide band-gap materials. This process is based on a chemical mechanical smoothening (CMS) technique, which is a unique subset of the novel chemical mechanical polishing (CMP) process developed by Sinmat to polish hard nitride and carbide materials. In this process, the chemicals in the slurry react to form a thin passivating layer (typically soft oxide layer) that is easily removed by the nanosized particles. The quality of polish would be determined by materials characterization and film growth techniques. Typically, conventional mechanical or chemo-mechanical polishing employs large (> 100 nm) hard particles (such as alumina, silica, etc.) that lead to significant scratching of the substrate. The proposed polishing technology is expected to increase the yield of GaN and SiC device. Wide band-gap (WBG) semiconductors such as GaN (gallium nitride) and SiC (silicon carbide) have been rapidly commercialized for blue and ultraviolet-light emitting devices, and high power/high frequency devices. Also, strong commercial interest exists in the application of engineering materials such as GaN and SiC for several high power/high temperature solid state devices for applications in power electronics, control and distribution circuits, and hybrid drive-train automobiles.