Analysis of the HF-Etihanol Cleaning Process on Silicon Wafers with 100 Vicinal Surfaces

Abstract

X-ray photoelectron spectroscopy (XPS) measurements on silicon surfaces cleaned by HF/Ethanol treatments are described using silicon wafers with (100) vicinal surfaces. The composition of the surfaces (Silicon, Oxygen, Fluorine and Carbon) has been measured leading to the conclusion of good passivated surfaces. Moreover, for each vicinal direction, the F 1s , C 1s ,O 1s and Si 2p lines have been decomposed into several components corresponding to different chemical bonds. The more significant results show that the percentages of the two components for Fluorine depend on the total amount of Oxygen and are related to the Si-F and Si-O-F bonds. On the other hand, the two complementary doublets necessary to fit the Si 2p band can be related to the Si-H and Si-F bonds and change with orientation and/or roughness of the considered surface. The native oxide formation also points out significant differences in the behaviour of each vicinal direction. The thickness and structure of the oxide and the remaining amount of Fluorine reflect the influence of the initial RMS-microroughness determined by Atomic Force Microscopy which changes from 0.05nm for (100) to 0. lnm for (911).