Atomically smooth gallium nitride surface prepared by chemical-mechanical polishing with S2O82−-Fe2+ based slurry

In this paper, a significant improvement of chemical-mechanical polishing on gallium nitride with S2O82−-Fe2+ based slurry is presented in detail. The results indicate that the S2O82−-Fe2+ additives possessed obvious effect to enhance the polishing efficiency of GaN, and successfully achieved good surface quality after polishing. The addition of complexing agent obviously improves the stability of catalytic system. Besides, we also studied the special change rule of atomic step-terrace topography from the surface of GaN to describe the material removal mechanism during CMP process. The results show that the removal of materials by CMP follows rigid rules, which may help to improve the material removal mechanism of CMP.