Abstract: The microroughness of silicon surfaces after pre-oxidation cleaning is studied using atomic force microscopy,and the cleaning mechanism is analyzed by building surface reaction and oxide layer models.The experimental results show that the oxide layer on a wafer’s the surface can eliminate the anisotropic etching in the ammonia solution.The RMS roughness of the surface is less than that obtained using the traditional RCA process,and it decreases with the increase of ammonia concentration after forming an oxide layer prior to RCA cleaning.

Key words: pre-oxidation,  oxide layer, anisotropic etching, microroughness