CMP of GaN using sulfate radicals generated by metal catalyst

A method for preparing atomically smooth gallium nitride (GaN) surface with high material removal rate that involves chemical mechanical polishing with sulfate radical (SO
₄
^-
) oxidizer and Fe
²⁺
activator in slurry is presented. The results indicate that complexing agent with Fe
²⁺
activator is the key point to obtain atomically smooth GaN surface and higher removal rate of GaN. Atomic force microscope (AFM) shows that the average surface roughness (Ra) is 0.0601nm.