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Title:Evolution of the surface morphology of homoepitaxial germanium(001) and heteropitaxial silicon(0.5) germanium(0.5)/germanium(001) deposited by molecular beam epitaxy at reduced temperatures
Author(s):Van Nostrand, Joseph Edward
Doctoral Committee Chair(s):Cahill, David G.
Department / Program:Materials Science and Engineerin
Discipline:Materials Science and Engineerin
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Physics, Condensed Matter
Engineering, Materials Science
Abstract:We present comprehensive experimental results on the fashion in which the Ge(001) surface roughens as a function of film thickness, deposition temperature, and substrate miscut. The results allow us to write empirical expressions for feature spacing and roughness amplitude of the growing surface over a wide range of film thicknesses and deposition temperatures. We show that layer-by-layer growth on a singular surface in the presence of a small Ehrlich-Schwoebel leads to mound formation, and, from our experimental results, we extract an activation energy for the Ehrlich-Schwoebel barrier of $\rm E\sb{ES}\approx 1meV$ for Ge(001). The effect of the Ehrlich-Schwoebel barrier does not diminish with an increase in deposition temperature, and hence the transition of the growth mode from multilayer to step flow is due to the competing process of smoothing becoming the dominant mechanism. Deposition on a vicinal surface miscut in the (011) results in the formation of elongated mounds bounded by $\{105\}$ facets.
Thin $\rm Si\sb{0.5}Ge\sb{0.5}/Ge(001)$ films deposited in the presence of tensile strain result in the formation of Shockley partial misfit dislocations and a subsequent stacking fault. The stacking faults extend to the film surface, where they impede step flow. This results in step bunching and the formation of rectangular mounds on the surface. Annealing these films results in an inversion of the mounds into pits.
Issue Date:1996
Rights Information:Copyright 1996 Van Nostrand, Joseph Edward
Date Available in IDEALS:2011-05-07
Identifier in Online Catalog:AAI9712469
OCLC Identifier:(UMI)AAI9712469

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