Atomic layer growth of SiO2 on Si(100) using SiCl4 and H2O in a binary reaction sequence

O. Sneh, M. L. Wise, A. W. Ott, L. A. Okada, S. M. George*

*Corresponding author for this work

Research output: Contribution to journalArticle

121 Scopus citations

Abstract

The atomic layer control of SiO2 growth can be accomplished using binary reaction sequence chemistry. To achieve this atomic layer growth, the binary reaction SiCl4 + 2H2O → SiO2 + 4 HCl can be divided into separate half-reactions: (A) SiOH*+SiCl4→SiOSiCl*3+HCl, SiCl*+H2O→SiOH*+HCl,. where the asterisks designate the surface species. Under the appropriate conditions, each half-reaction is complete and self-limiting and repetitive ABAB... cycles should produce layer-by-layer-controlled SiO2 deposition. The atomic layer growth of SiO2 thin films on Si(100) was achieved at temperatures from 600-680 K with reactant pressures from 1-50 Torr. These experiments were performed in a small high pressure chamber situated in an ultrahigh vacuum (UHV) apparatus. This design couples high pressure conditions for film growth with an UHV environment for surface analysis using laser-induced thermal desorption (LITD), temperature-programmed desorption (TPD) and Auger electron spectroscopy (AES). The controlled growth of a stoichiometric and chlorine-free SiO2 film on Si(100) was demonstrated using these techniques. SiO2 growth rates of approximately 0.73 ML of oxygen (1.1 Å of SiO2) per AB cycle were obtained at 600-680 K. Additional vibrational spectroscopic studies performed in a second vacuum chamber utilized transmission Fourier transform infrared (FTIR) experiments on high surface area, oxidized porous silicon to monitor the surface species during the binary reaction sequence chemistry. These FTIR measurements observed the SiCl stretching vibration at 625 cm-1 and the SioH vibration at 3740 cm-1 and confirmed that each half-reaction was complete and self-limiting. These studies illustrate the feasibility of atomic-layer-controlled SiO2 growth and have determined the reactant pressures and substrate temperatures required for the SiO2 binary reaction sequence chemistry.

Original languageEnglish (US)
Pages (from-to)135-152
Number of pages18
JournalSurface Science
Volume334
Issue number1-3
DOIs
StatePublished - Jul 10 1995

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

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