Steric and electronic interactions between source gas and substrate surface during the Al-CVD/Al selective epitaxy process as investigated by quantum chemical calculations

R. Vetrivel, R. Yamauchi, H. Yamano, Momoji Kubo, Akira Miyamoto, T. Ohta

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

We have performed quantum chemical calculations by semiempirical MNDO and by density functional theory (DFT) to rationalize the selection of an Al source gas for the selective Al-CVD/Al process. The electronic properties of Al(CH3)nH3-n, (n = 0 to 3) and their adsorption complexes over representative aluminum metal clusters were calculated. Initially, the interaction of Al source gases with a representative Al metal was studied by both MNDO and DFT methods and the results were found to be qualitatively comparable. Further detailed calculations were performed by MNDO to understand the interaction of Al(CH3)nH3-n with larger cluster models of Al substrate as well as insulator silica surface. The results of the calculations indicate that the interaction energy between the substrate and the source are controlled by both steric and electronic factors. The steric factor favors the interaction of unsubstituted hydride, namely aluminum trihydride and the electronic factor favors the interaction of maximum substituted aluminum organic, namely trimethyl aluminum with the substrates. However, dimethyl aluminum hydride has the most favorable interaction energy with the Al metal, since it has the right combination of steric and electronic factors. The interaction energy of DMAH with chlorided silica surface is more favorable than the untreated silica surface.

Original languageEnglish
Pages (from-to)516-522
Number of pages7
JournalApplied Surface Science
Volume82-83
Issue numberC
DOIs
Publication statusPublished - 1994 Dec 2

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics
  • Physics and Astronomy(all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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