Study of silicon contamination and near-surface damage caused by CF ₄/H₂ reactive ion etching

Silicon surfaces which had been exposed to a CF4 /H2 plasma have been characterized by x-ray photoelectron spectroscopy, ellipsometry, He ion channeling, and H profiling techniques. Plasma exposure leads to the deposition of a thin (∼30 Å thick) C,F-polymeric layer. Hydrogen and/or damage (displaced Si atoms) can be detected in the near-surface region up to a depth in excess of 400 Å from the Si surface.