Novel abrasive-free planarization of 4H-SiC (0001) using catalyst

A new abrasive-free planarization method for silicon carbide (SiC) wafers was proposed using the catalytic nature of platinum (Pt). We named it catalyst-referred etching (CARE). The setup equipped with a polishing pad made of Pt is almost the same as the lapping setup. However, CARE chemically removes SiC with an etching agent activated by a catalyst in contrast to mechanical removal by the lapping process. Hydrofluoric acid which is well known as an etchant of silicon dioxide (SiO₂) that cannot etch SiC, was used as the source of the etching agent to SiC. The processed surfaces were observed by Nomarski differential interference contrast (NDIC) microscopy, atomic force microscopy (AFM), and optical interferometry. Those observations presented a marked reduction in surface roughness. Moreover, low-energy electron diffraction (LEED) images showed that a crystallographically well-ordered surface was realized.