Pseudomorphic Semiconducting Heterostructures from Combinations of AIN, GaN and Selected SiC Polytypes: Theoretical Advancement and its Coordination with Experimental Studies of Nucleation, Growth, Characterization and Device Development
Annual letter rept. 1 Jan-31 Dec 91,
NORTH CAROLINA STATE UNIV AT RALEIGH DEPT OF MATERIALS SCIENCE AND ENGINEERING
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Cubic solid solutions of A1N and SiC have been epitaxially deposited for the first time in this film form on Beta-SiC films grown on Si100 using gas-source molecular beam epitaxy GSMBE. Specific studies of the deposition of unintentionally-doped beta-SiC on Si100 and A1-doped beta-SiC on alpha 6H- SiC0001 have also been achieved via GSMBE. Cross-sectional TEM confirmed the epitaxial growth of the three types of films. A low concentration of double positioning boundaries was observed in the material deposited on alpha6H-SiC. The initial stages of nucleation and thin film growth of A1N and GaN on sapphire and alpha6H-SiC single crystals were also investigated. No significant changes in the substrate surface chemistry was observed for growth on sapphire however, Si4N4 was observed on the SiC surface as a result of ion bombardment prior to deposition. The growth of GaN on sapphire followed a Stranski-Krastanov growth mode, while on SiC, it appeared to be three-dimensional. By contrast, A1N grew on both substrates initially by a layer-by-layer mode. Ultraviolet radiation during deposition did not produce any significant changes in the nucleation and growth of these materials.
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