Core-level shifts of silicon–hydrogen species on chemically treated Si surfaces studied by high-resolution x-ray photoelectron spectroscopy

Chemical shifts of Si–Hx (x=1,2) species on Si surfaces obtained by ex situ chemical treatment have been evaluated by high-resolution x-ray photoelectron spectroscopy at a take-off angle of 5°. Optimizing the water rinse and sample loading conditions enables identification of the Si–Hx components of the Si 2p core-level spectra, whose intensities display strong dependence on crystallographic orientation and surface treatment. NH4F-treated Si(111) exhibits almost exclusive monohydride termination which induces a chemical shift of 250 meV relative to the bulk component. On the other hand, 4.5% HF-treated Si(111) and 1% HF-treated Si(100) surfaces show increased dihydride termination with an associated shift of 480 meV.