Photo-electron emission and atomic force microscopies of the hydrogen etched 6H-SiC(0 0 0 1) surface and the initial growth of GaN and AlN

J. D. Hartman, K. Naniwae, C. Petrich, R. J. Nemanich, R. F. Davis

Research output: Contribution to journalArticle

6 Scopus citations

Abstract

Photo-emission electron microscopy (PEEM) and atomic force microscopy (AFM) have been used to characterize the surfaces of hydrogen etched 6H-SiC(0 0 0 1) wafers and the microstructure of the initial stages of growth of GaN and AlN on these surfaces via molecular beam epitaxy. The PEEM images were obtained using a free electron laser as the photon source. A stepped structure was evident in these images of the surfaces etched at 1600-1700 °C for 15 min. Comparison with the AFM images revealed that emission was occurring from the intersection of the steps and the terraces. Images of the initial stages of deposition of the GaN thin films at 700 and 800 °C revealed three-dimensional island growth. The degree of coalescence of these films was dependent upon the step structure: regions containing steps having unit cell height exhibited complete or nearly complete coalescence; regions containing steps with half unit cell height showed voids in the films parallel to the steps. PEEM of the initial stages of growth of AlN revealed immediate nucleation and rapid coalescence during deposition at 900 °C, except in areas on the substrate surface containing steps having half unit cell height. Incomplete coalescence and pits were also observed in the latter areas.

Original languageEnglish (US)
Pages (from-to)428-436
Number of pages9
JournalApplied Surface Science
Volume242
Issue number3-4
DOIs
StatePublished - Apr 15 2005
Externally publishedYes

Keywords

  • Aluminum nitride
  • Gallium nitride
  • Molecular beam epitaxy
  • Photo-emission electron microscopy
  • Silicon carbide
  • Stepped single crystal surfaces

ASJC Scopus subject areas

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

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