Stabilization method of transition metal catalyst for high efficiency catalyst-referred etching (CARE) of silicon carbide

Inhalt:
Previously, we developed “Catalyst-Referred Etching (CARE)” as a new polishing method that does not require abrasives. In this method, using pure water as the etchant and Pt as the catalyst, we achieved an atomically well-ordered surface with a step-terrace structure on the functional materials, such as silicon carbide (SiC), gallium nitride (GaN), and the metallic oxide. However, the removal rate was still insufficient for industrial production. Therefore, in this study, to improve the removal rate, we attempted to use nickel, which showed excellent catalytic activity in CARE. However, the removal rate suddenly decreased after 60 minutes when using Ni in CARE because Ni is oxidized easily, thus its catalytic activity decreases. To overcome this problem, we suggest the electrochemical control of the Ni condition to maintain its high catalytic activity, leading to stable CARE processing. Consequently, the removal rate was stable in the long term under the potential control. This result indicates that this potential control method can maintain Ni’s catalytic activity and is very effective for high efficiency polishing of functional materials. Keywords: functional material, polishing, step-flow-type etching, catalyst, transition metal, nickel, potential control