Effects of ultra-smooth surface atomic step morphology on chemical mechanical polishing (CMP) performances of sapphire and SiC wafers

Towards sapphire and SiC wafer, clear and regular atomic step morphology could be observed all-over the surface via AFM. However, the variations of atomic step widths and step directions are different on the whole of different wafer surfaces: that on sapphire wafer are uniform, while that on SiC wafer are distinct. The effects of atomic step width on removal rate are studied. Removal model of super-hard wafer to realize atomically ultra-smooth surface is proposed. The variations of atomic step morphology toward different defects on sapphire and SiC wafers surface are analyzed, and the formation mechanism is discussed.