Accession Number : ADA304546

Title :   Interface Properties of Wide Bandgap Semiconductor Structures.

Descriptive Note : Semiannual technical rept. 1 Jul-31 Dec 95,

Corporate Author : NORTH CAROLINA STATE UNIV AT RALEIGH

Personal Author(s) : Davis, Robert F. ; Nemanich, R. J. ; Bedair, S. ; Bernholc, J. ; Sitar, Z.

PDF Url : ADA304546

Report Date : DEC 1995

Pagination or Media Count : 266

Abstract : A surface analytical study of bias enhanced nucleation of diamond on TiC(111) indicated that C vacancies form at the substrate and that the procedure may result in enhanced surface diffusion. Oriented diamond growth has been achieved on both (100) and (111) Ni substrates. A key aspect of the process is the formation of a molten Ni-C-H surface layer that promotes the nucleation of oriented particles. Experiments have been initiated to explore transmutation doping of B-doped homoepitaxial diamond by conversion of B to Li through neutron irradiation. Theoretical studies indicate that alternating exposure of hydrocarbon and fluorocarbon precursors may be suitable for ALE growth on diamond (110) surfaces. Field emission from diamond coated, needle shaped emitters demonstrated a significant enhancement of the total emission current and improved stability of the tip. A series of different ex situ chemical based techniques have been explored for cleaning of 6H-SiC surfaces. Results indicated that 0 bonded to C on the surface was not easily removed. The impurity concentrations were measured for epitaxial SiC films on 6H-SiC(0001) and 3C-SiC(111) that were prepared by gas source MBE using S1H4 and C2H2. MIS diodes of Al/AlN/SiC were prepared by gas source MBE and characterized with C-V measurements. Ohmic contacts on p-type SiC were obtained using Ni/NiAl and annealing to 10000C. AIGaN films were grown directly on 6H-SiC, and the films were characterized with TEM, XRD, and cathodoluminescence.

Descriptors :   *SILICON CARBIDES, *SOLID STATE CHEMISTRY, DIODES, INTERFACES, SHAPE, STRUCTURES, DIAMONDS, ENERGY GAPS, SUBSTRATES, NUCLEATION, IMPURITIES, NITRIDES, FIELD EMISSION, SURFACE PROPERTIES, HYDROCARBONS, CONCENTRATION(COMPOSITION), CATHODOLUMINESCENCE, EMITTERS, FLUORINATED HYDROCARBONS, P TYPE SEMICONDUCTORS, ELECTRIC CONTACTS, NICKEL COMPOUNDS, NEEDLES, MOLECULAR BEAM EPITAXY.

Subject Categories : Solid State Physics

Distribution Statement : APPROVED FOR PUBLIC RELEASE