Defects in amorphous and solid phase epitaxial silicon

G. Radnoczi, M. A. Hasan, J. E. Sundgren

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

The microstructural morphology of amorphous Si (a-Si) layers deposited in ultrahigh vacuum, as well as crystalline Si grown by solid phase epitaxy (SPE), was studied as a function of Al doping and vapour beam incidence angle. The microstructure of the films was investigated using cross-section transmission electron microscopy. All a-Si layers have a columnar structure, with an average column width of ≤ 5 nm. The direction of the columns abruptly changes with the change of deposition direction and shows local column tilts and void formation at substrate surface irregularities. These built-in defects in the a-Si films also influence the defect structure in epitaxial Si films grown by SPE. Voids are initially aligned along the column directions and extra voids form owing to irregularities of the columnar structure. Doping of amorphous Si with Al to 1018-1020 cm-3 does not leave detectable effects in the amorphous structure itself, but will increase the void density of the re-grown SPE Si layers. Furthermore, segregation of Al resulting in metallic inclusions in the amorphous crystalline interface causes metal induced crystallization of Si at temperatures far below the normal SPE regrowth temperature, thus preventing the formation of single crystalline silicon in a single-step process.

Original languageEnglish
Pages (from-to)39-44
Number of pages6
JournalThin Solid Films
Volume240
Issue number1-2
DOIs
Publication statusPublished - Mar 15 1994

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Metals and Alloys
  • Materials Chemistry

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