An infrared study of thin-film formation on Si and Ge surfaces treated with aqueous NH4F and HF

J. Yota, Veronica Burrows

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

The surface chemistry of Si and Ge after treatment with hydrofluoric acid buffered with ammonium fluoride (BHF) was studied using surface infrared spectroscopy. For each of these materials, the BHF not only dissolved the native oxide, but also deposited a thin inorganic film comprised of ammonium salts (NH4F and NH4F.HF). Through one or more complex reactions with the substrate, these salts slowly disappear as the thermodynamically very stable hexafluorometallate compounds [(NH4)2SiF 6 and (NH4)2GeF6] form. The NH 4F.HF disappearance correlates directly with the hexafluorometallate formation. Though the original fluoride and bifluoride salts are quite soluble in alcohols as well as in aqueous solutions, the hexafluorometallates are completely insoluble in alcohols, and can only be removed by thorough water rinse.

Original languageEnglish (US)
Pages (from-to)7369-7371
Number of pages3
JournalJournal of Applied Physics
Volume69
Issue number10
DOIs
StatePublished - 1991

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salts
fluorides
alcohols
thin films
hydrofluoric acid
infrared spectroscopy
chemistry
aqueous solutions
oxides
water

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

Cite this

An infrared study of thin-film formation on Si and Ge surfaces treated with aqueous NH4F and HF. / Yota, J.; Burrows, Veronica.

In: Journal of Applied Physics, Vol. 69, No. 10, 1991, p. 7369-7371.

Research output: Contribution to journalArticle

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