X-Ray Photoelectron Spectroscopy and Optical Reflectivity Studies of Si Surfaces Prepared by Chemical Etching

Abstract

Complementary X-ray photoelectron spectroscopy and optical reflectivity studies of crystalline Si(111) surfaces prepared by two different wet chemical etching processes were performed. These included aqueous HF solution etch or diluted CP-4 bath. Optical reflectivity spectra of Si surfaces, measured in the range 3.7-11 eV, were found strongly dependent on the applied etching process. Analysis of the core level X-ray photoelectron spectroscopy data has shown similarity of the surface structure, irrespectively of the etching procedure. Finally, comparison of optical reflectivity and valence 'band X-ray photoelectron spectra revealed a qualitative correlation between them indicating dominant influence of the bulk (here, the subsurface region containing polishing-induced defects) in the case studied. This paper is the first one which presents correlations between optical reflectivity and X-ray photoelectron spectroscopy data for Si and thus illustrates a bulk sensitivity of both techniques considered.

Adsorption of Oxygen on HF-Etched Si(111) Surfaces: XPS Study

“…B' refers to the XPS spectra of the B sample, detected for O = 20°. It was generally found in the standard case (A) that the Si 2p core-level spectra do not exhibit (see [5]) any additional features indicative of a chemical shift toward higher binding energies (EB), that is characteristic of Si surface covered (even partially) with suboxides and/or SiO2 (e.g. [3,7,8]) or with SiFx [9].…”

“…Such deoxidation occurs in a final stage of wet chemical treatment by dipping Si crystal in dilute HF, followed by adequate rinse. X-ray photoelectron spectroscopy (XPS) has been commonly used for investigating the microscopic structure of the HF-etched silicon surface, including single crystalline [1][2][3][4][5] and porous Si (e.g. [6]).…”