Accession Number : ADA320546

Title :   Selected Energy Epitaxial Deposition and Low Energy Electron Microscopy of AlN, GaN and SiC Thin Films.

Descriptive Note : Quarterly technical rept. 1 Oct-31 Dec 96,

Corporate Author : NORTH CAROLINA STATE UNIV AT RALEIGH

Personal Author(s) : Davis, R. F. ; Lamb, H. H. ; Tsong, I. S. ; Bauer, E. ; Chen, E.

PDF Url : ADA320546

Report Date : 31 DEC 1996

Pagination or Media Count : 24

Abstract : The stoichiometry and the atomic and electronic structure of the anion and cation terminated (0001) surfaces of GaN and AlN are being investigated using the multicenter tight-binding formalism. The surfaces are described within the slab-supercell formalism. Results show that an unreconstructed (1 x 1) surface is highly unstable with respect to surface reconstructions that change the surface stoichiometry of the outermost layers and, therefore, stabilize the atomic structure and eliminate the surface polarity. Growth of stoichiometric and smooth AlN and GaN thin films on Si(100) and off-axis 6H-SiC(0001) has been achieved using a seeded supersonic molecular beam under conditions suitable for observation in the low energy electron microscope (LEEM). An arc heated N source is being currently tested for intensity and beam composition. Films of GaN have also been achieved on sapphire substrates using a new multichamber selected energy epitaxy deposition (SEED) system. In situ RHEED and SEM results show the films to have good morphology. Mass selected, essentially monoenergetic and chemically pure N2(+) and N(+) ions beams with energies of 20 eV and FWHM 1 eV and useful for nitride film deposition were extracted from the Colutron ion-beam systems.

Descriptors :   *THIN FILMS, *EPITAXIAL GROWTH, *NITRIDES, *ELECTRON MICROSCOPY, *DEPOSITION, *LOW ENERGY, *ALUMINUM, *GALLIUM, *SILICON CARBIDES, ELECTRONICS, CATIONS, ELECTRON MICROSCOPES, SUBSTRATES, ION BEAMS, MOLECULAR BEAMS, SURFACES, SAPPHIRE, ELECTRON ENERGY, SUPERSONIC CHARACTERISTICS, POLARITY, ANIONS, STOICHIOMETRY, ATOMIC STRUCTURE.

Subject Categories : Inorganic Chemistry
      Crystallography
      Atomic and Molecular Physics and Spectroscopy
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE