Rapid Planarization Method by Ultraviolet Light Irradiation for Gallium Nitride Using Platinum Catalyst

We have developed a chemical process for atomic planarization of gallium nitride (GaN) using a platinum catalyst and ultraviolet (UV) light irradiation. The process is mediated by a hydrolysis reaction catalyzed by platinum as a solid catalyst. Because the reaction occurs selectively from the step edges, a flat surface composed of a straight step-and-terrace structure is obtained. In the absence of UV light, owing to the low step edge density, the removal rate is quite slow, approximately 1 nm/h. In contrast, under UV light, etch pits are formed on the terraces by photo-electrochemical etching causing an increase in the step edge density. We achieved surface planarization with a removal rate of 9.6 nm/h assisted by irradiation with UV light.