Accession Number : ADA295636

Title :   Pseudomorphic Semiconducting Heterostructures from Combinations of AlN, GaN and Selected SiC Polytypes: Theoretical Advancement and its Coordination with Experi mental Studies of Nucleation, Growth, Characterization and Device Development.

Descriptive Note : Rept. for 1 Jan-30 Jun 95,

Corporate Author : NORTH CAROLINA STATE UNIV AT RALEIGH DEPT OF MATERIALS SCIENCE AND ENGINEERING

Personal Author(s) : Davis, R. F. ; Aboelfotch, O. ; Kern, S. ; Linthicum, K. ; Sumakeris, J.

PDF Url : ADA295636

Report Date : JUN 1995

Pagination or Media Count : 24

Abstract : The use of NH3 as an alternative to ECR in the gas source(GS) MBE of GaN has resulted in an increase in the growth rate and a sharp peak at 354 nm in the PL spectrum. The use of an ammonia cracker cell was investigated. Stoichiometric GaN films have also been deposited on Al2O3(0001), Si(001) and Si(111) substrates using an NH3 seeded free He jet and an effusive triethylgallium (TEG) source. Very uniform films have been achieved at low temperatures. Work continues toward the construction of a dual supersonic beam deposition system with an attached UHV analysis system. The results of GaN film deposition in the current single beam system and progress toward the completion of the next system are detailed. MIS diodes (Al/AlN/Alpha-SiC(0001) were fabricated with various thicknesses of AlN by GSMBE. High frequency C-V measurements between 10kHz and 1 MHz showed that thin layers (<1000A) of AlN exhibited moderate leakage currents; thicker layers reduced this problem. The diodes could be accumulated and depleted over the entire frequency range studied. Inversion was not achieved at room temperature. A dependence of the dielectric constant on frequency was also observed. jg

Descriptors :   *SEMICONDUCTORS, *NUCLEATION, *ALUMINUM, *GALLIUM, *SILICON CARBIDES, DIODES, FREQUENCY, MEASUREMENT, THICKNESS, LOW TEMPERATURE, HIGH FREQUENCY, LAYERS, GROWTH(GENERAL), PHOTOLUMINESCENCE, STRUCTURES, FILMS, EPITAXIAL GROWTH, MOLECULAR BEAMS, NITRIDES, ROOM TEMPERATURE, AMMONIA, DEPOSITION, DIELECTRIC PROPERTIES, THINNESS, HELIUM, SUPERSONIC FLOW, CURRENTS, STOICHIOMETRY, ETHYL RADICALS, PARTICLE BEAMS, GAS FLOW, ULTRAHIGH VACUUM.

Subject Categories : Inorganic Chemistry
      Organic Chemistry
      Physical Chemistry
      Electrical and Electronic Equipment
      Crystallography
      Electricity and Magnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE