Thesis Title

An Investigation of the Surface Properties of Sic For the Growth of Gan Thin Films and Epilayers

Date of Graduation

Summer 2000

Degree

Master of Science in Materials Science

Department

Physics, Astronomy and Materials Science

Committee Chair

Shyang Hwang

Subject Categories

Materials Science and Engineering

Abstract

6H-SiC is currently the best subtrate used in the growth of III-V quantum heterostructures due to a negligible lattice mismatch (~3.5%) between the substrate and the epilayer, compared to sapphire (14%). Considerable amount of research is currently being done all over the world on these III-V compounds, particularly the GaN based compounds, due to their characteristic absorption in the blue region of the electromagnetic spectrum. However, the success of achieving high quality thin films that would produce the needed quantum effect depends not only on the growth parmeters but also on the preparation of the surface of the SiC substrate. The project aimed to determine the most efficient method in the preparation of the substrate. Surface analysis of the SiC using Auger Electron Spectroscopy (AES) and X-ray Photoelectron Spectroscopy (XPS) showed that thermal annealing of the SiC substrate induces graphitization at temperatures as low as 840 °C, but surface oxides are removed only at 940 °C. UHV Si-beam etching was proposed as a cleaning method that would effectively clean the surface of oxides/carbon contaminants at low temperatures without the onset of graphitization. A UHV Si-beam etching apparatus, with a newly purchased evaporator used as the Si source, was built from concept, was designed and was successfully fabricated in-house. Assembly and test of the apparatus showed that it is capable of cleaning the substrate through resistive heating. Due to uncontrollable events, further experiments for its successful operation were recommended.

Copyright

© Jasper S Cabalu

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