Accession Number : ADA267966


Title :   Low Temperature Deposition and Characterization of N- and P-Type Silicon Carbide Thin Films and Associated Ohmic and Schottky Contacts


Descriptive Note : Semi-annual rept. 1 Jan-30 Jun 93,


Corporate Author : NORTH CAROLINA STATE UNIV AT RALEIGH


Personal Author(s) : Davis, Robert F


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a267966.pdf


Report Date : Jun 1993


Pagination or Media Count : 38


Abstract : Monocrystalline films of SiC were grown on alpha (6H)-SiC(0001) wafers using disilane (Si2H6) and ethylene (C2H4) by gas-source MBE at 1050 deg C. The nucleation and growth of cubic beta-SiC(111) on the surface terraces of the hexagonal 6H-SiC rather than on the step surfaces and the resultant formation of double positioning boundaries is discussed. The reconfiguration of the growth system leading to enhanced control over polytype deposition is also described. Thin film contacts of Ti, Pt, Hf, and Co were deposited in UHV onto unheated, n-type vicinal alpha(6H)-SiC(0001) films by electron beam evaporation. All as-deposited contacts were rectifying with low ideality factors (nl.l), low leakage currents and Schottky barrier heights between 0.85 eV and 1.15 eV. The lowest leakage currents were 5xl0-8 A/CM2 at-10V. Titanium and Pt remained relatively stable after annealing at 700-750 deg C; whereas, Co became ohmic after annealing for two minutes at 1000 deg C. UV photoemission studies on both SiC/metal interfaces and the surface of AlN(0001) deposited on SiC have been initiated. A major emphasis is on surface cleanliness prior to metal deposition. A spectral feature observed in the AlN is attributed to the initial indication of negative electron affinity in this material. Chemical interdiffusion between alpha (6H)-SiC wafers and epitaxially deposited 2H-AlN films are under investigation within the temperature range of 1500 deg C to 1700 deg C. SiC, AlN, Gas source molecular beam epitaxy, Transmission electron microscopy, Metal contacts, Ti, Pt, Hf, Co, Ideality factors, Leakage currents, Schottky barrier heights, UV Photoemission, Negative electron affinity, Chemical interdiffusion


Descriptors :   *LOW TEMPERATURE , *THIN FILMS , *DEPOSITION , *METAL CONTACTS , *SILICON CARBIDES , *SCHOTTKY BARRIER DEVICES , SCANNING , MEASUREMENT , SPECTROSCOPY , CHEMICALS , MATERIALS , EPITAXIAL GROWTH , NUCLEATION , SILANES , PHOTOELECTRIC EMISSION , ELECTRON ENERGY , ELECTRON BEAMS , ETHYLENE , SURFACES , ELECTRON MICROSCOPY , GASES , MOLECULAR BEAMS , ULTRAHIGH VACUUM , COBALT , EVAPORATION , LEAKAGE(ELECTRICAL) , WAFERS , ELECTRIC CURRENT , DIFFUSION , TITANIUM , PLATINUM , BARRIERS , SEMICONDUCTOR DEVICES , SINGLE CRYSTALS , ENERGY , INTERFACES , HAFNIUM , TEMPERATURE , ANNEALING


Subject Categories : Physical Chemistry
      Electrical and Electronic Equipment
      Electricity and Magnetism
      Solid State Physics


Distribution Statement : APPROVED FOR PUBLIC RELEASE