Date of Award

Fall 1994

Document Type

Thesis

Degree Name

Master of Science in Applied Physics - (M.S.)

Department

Physics

First Advisor

Chin, Ken K.

Second Advisor

Hensel, John Charles

Third Advisor

Russo, Onofrio L.

Abstract

In this work, we grew the InxGa1-xAs/GaAs/Si (GaAs as buffer layer) by MBE technique. The surface of the buffer layer became microscopically rough as the thickness of the buffer layer increased and the growth mode of GaAs on Si underwent a change from three-dimensional to two-dimensional during the initial growth stage as indicated on the Reflection High Energy Electron Diffraction (RHEED) screen. The Scattering Electron Microscopy (SEM) observation of the etched surface of GaAs on Si showed that the structure of the buffer layer tended to be poly-crystalline and it was possible that a predominant orientation occurred at next step of the epitaxy of InxGa1-xAs/GaAs/Si. The role of contaminations such as C and SiO2 as crystallization centers was revealed by Photoluminescence (PL).

SEM study of interfaces of InxGa1-xAs/GaAs/Si showed that most of the threading dislocations propagated through the growing layer without changing their running direction which was close to the normal to the plane of the layer-by-layer growth for the large lattice mismatched system. From cross-hatch,we also obtained the linear dislocation densities along two <110> directions, 200cm-1 and 1200cm-1 respectively. In addition, the SEM topographies of the epitaxial growth of In0.5Ga0.5As on tilted and untilted Si substrates indicated that in the case of using tilted substrates, the island growth would not be isotropic and the islands tend to be elongated running parallel to the steps.

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