A cost-effective alkaline multicrystalline silicon surface polishing solution with improved smoothness

In the present paper, intragain surface morphology of multicrystalline silicon (mC-Si) wafer surface of area 3 mu m x 3 mu m polished by the acid-based solution comprising of hydrofluoric (HF), nitric (HNO3) and acetic (CH3COOH) acids and new alkaline solution containing sodium hydroxide (NaOH) and sodium hypochlorite (NaOCl) has been studied using an atomic force microscope (AFM). From the roughness and section analysis study of the intergrain surface by the AFM, it is revealed that the NaOH-NaOCl polishing process is quite superior to the existing acid polishing one. Quantitative measurements indicate better smoothness of polished silicon surface after the NaOH-NaOCl treatment as compared with acid polishing. Also process cost per wafer involved in the NaOH-NaOCl polishing process is far lower than that by the acid polishing process along with additional advantageous features of high productivity, environment friendliness and safety. All these factors finally contribute to make the NaOH-NaOCl solution a better polisher for mC-Si surface. (C) 2009 Elsevier B.V. All rights reserved.