Atomic Scale Flatness of Chemically Cleaned Silicon Surfaces Studied by Infrared Attenuated-Total-Reflection Spectroscopy

Abstract

Hydrogen-terminated Si(111) and Si(100) surfaces obtained by aqueous HF or pH-modified (pH=5.3) buffered-HF (BHF) treatments have been characterized by a Fourier transform infrared (FT-IR) attenuated-total-reflection (ATR) technique. The BHF treatment provides better surface flatness than the HF treatment. Pure water rinse is effective for improving the Si(111) surface flatness, while this is not the case for Si(100) because the pure water acts as an alkaline etchant and promotes the formation of (111) microfacets or microdefects on the (100) surface.