Accession Number : ADA267527


Title :   Atomic Layer Epitaxy Group 4 Materials: Surface Processes, Thin Films, Devices and Their Characterization


Descriptive Note : Semi-Annual rept. 1 Jan-30 Jun 1993


Corporate Author : NORTH CAROLINA STATE UNIV AT RALEIGH


Personal Author(s) : Davis, Robert F ; Bedair, Salah ; El-Masry, Nadia ; Glass, Jeffrey T


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a267527.pdf


Report Date : Jun 1993


Pagination or Media Count : 43


Abstract : The maximum temperature at which self-terminating monolayers of Si can be formed on Si(100) from Si2H6 has been determined to be 570 deg C. As such, the chemical reactivity Of C2H4 has been determined to be insufficient at this temperature, and acetylene has been selected as the successor C precursor due to its superior reactivity and chemisorption properties. A cryogenic purifier for removing acetone has been commissioned. Trenched Si(100) wafers are also being made to assess the ALE process for sidewall deposition uniformity and future bipolar devices. Nonstoichiometric, Si-rich SiC has been produced with an associated decrease in the band gap. An AES/XPS UHV analytical system and associated ALE deposition system has been commissioned and integrated into a much larger surface science system. These dual systems will allow a thorough study and characterization of the both the initial nucleation of SiC and the overall ALE growth process of SiC. Tetramethylsilane and hexamethyldisilane have been deposited onto Si substrates in a hot filament CVD chamber to investigate their ability to promote ALE of diamond under DC biasing and a variety of system parameters. An electron gun and heating stage has been added to the growth chamber to enable AES and substrate heating. Good quality diamond films have been nucleated on deposited interlayers of both precursor compounds. The films have been examined by SEM and Raman spectroscopy. Good quality epitaxial films of CeO2 have been grown on Si(111) using laser ablation. Atomically clean substrates and slow growth rates were determined necessary for epitaxy.


Descriptors :   *LAYERS , *MATERIALS , *EPITAXIAL GROWTH , *GROUP IV COMPOUNDS , *THIN FILMS , *CHEMISORPTION , *ATOMIC STRUCTURE , ABLATION , TEMPERATURE , SCANNING ELECTRON MICROSCOPES , COMPOSITE MATERIALS , REACTIVITIES , CERIUM , X RAY PHOTOELECTRON SPECTROSCOPY , QUALITY , DEPOSITION , SURFACES , LASERS , NUCLEATION , SUBSTRATES , VAPOR DEPOSITION , ACETYLENES , DIOXIDES , BIPOLAR SYSTEMS , ELECTRON GUNS , CHAMBERS , SILICON CARBIDES , CRYOGENICS , AUGER ELECTRON SPECTROSCOPY , ACETONES , GUNS , WAFERS , FILAMENTS , STOPPING , SILANES , HEATING , CHEMICAL REACTIONS , DIAMONDS , RATES , RAMAN SPECTROSCOPY , PRECURSORS , PARAMETERS , HYDRIDES , METHYL RADICALS


Subject Categories : Laminates and Composite Materials
      Crystallography
      Atomic and Molecular Physics and Spectroscopy
      Solid State Physics


Distribution Statement : APPROVED FOR PUBLIC RELEASE