Oxidation of silicon (100): Experimental data versus a unified chemical model

P. Thanikasalam, T. K. Whidden, D. K. Ferry

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

It has been observed in many studies of oxidation kinetics that silicon dioxide growth in the thin regime (<30 nm) is faster than the predictions of the linear-parabolic Deal-Grove relationship. We have developed a conceptual and mathematical model for the thermal oxidation of silicon which is based on an initial dissociative chemisorption of molecular oxygen on the 2×1 silicon (100) surface followed by subsequent diffusion and dissociative reactions of molecular oxygen at the Si/SiO2 interface. This model accounts for current experimental observations on the structural modification of the reconstructed surface to a 1×1 superlattice on limited exposure to molecular oxygen and provides a mechanistic rationale for the self-limiting mechanism of the oxide film at ∼0.6 nm during low-temperature oxidation processes. The rate-equation model, consistent with the proposed reactions at the Si/SiO2 interface, has been refined to give an excellent fit to experimental data within all thickness regimes, but especially in the initial rapid growth regime where the growth rate is proportional to (Po2)1/2. The rate equation reduces to a linear dependence on oxygen partial pressure in the thicker regime, where it predicts classic Deal-Grove behavior. We present the development of the model for oxidations performed between 780-1100 °C consistent with observed oxide growth and film properties. The activation energies for the reaction-controlled regime and the diffusion-controlled regime are consistent with literature data. We observe a sharp transition in a characteristic length parameter at ∼950 °C which may be possibly due to the experimentally observed change in oxide film density. A detailed analysis and explanation is presented.

Original languageEnglish (US)
Pages (from-to)2840-2844
Number of pages5
JournalJournal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
Volume14
Issue number4
StatePublished - 1996

Fingerprint

Molecular oxygen
Silicon
Oxidation
oxidation
silicon
oxygen
Oxide films
oxide films
Chemisorption
Partial pressure
chemisorption
partial pressure
mathematical models
Activation energy
Silica
Mathematical models
activation energy
silicon dioxide
Kinetics
Oxides

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Physics and Astronomy (miscellaneous)
  • Surfaces and Interfaces

Cite this

Oxidation of silicon (100) : Experimental data versus a unified chemical model. / Thanikasalam, P.; Whidden, T. K.; Ferry, D. K.

In: Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures, Vol. 14, No. 4, 1996, p. 2840-2844.

Research output: Contribution to journalArticle

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