https://murray.cds.caltech.edu/index.php?action=history&feed=atom&title=Modeling_and_Control_of_Epitaxial_Thin_Film_Growth 2026-10-30T20:51:36Z Revision history for this page on the wiki MediaWiki 1.44.2 https://murray.cds.caltech.edu/index.php?title=Modeling_and_Control_of_Epitaxial_Thin_Film_Growth&diff=19950&oldid=prev 2016-05-15T06:19:06Z

<p>htdb2wiki: creating page for 2002_mag02-phd.html</p> <p><b>New page</b></p><div>{{HTDB paper<br /> | authors = Martha A. Gallivan<br /> | title = Modeling and Control of Epitaxial Thin Film Growth<br /> | source = Caltech Mechanical Engineering<br /> | year = <br /> | type = Ph.D. Dissertation<br /> | funding = NSF/fship, MURI/vem, MURI/ferro<br /> | url = http://www.cds.caltech.edu/~murray/preprints/mag02-phd.pdf<br /> | abstract = <br /> Thin &amp;#64257;lm deposition is a manufacturing process in which tolerances may approach<br /> the size of individual atoms. The &amp;#64257;nal film is highly sensitive to the processing<br /> conditions, which can be intentionally manipulated to control film properties. A<br /> lattice model of surface evolution during thin film growth captures many important<br /> features, including the nucleation and growth of clusters of atoms and the<br /> propagation of atomic-height steps. The dimension of this probabilistic master<br /> equation is too large to directly simulate for any physically realistic domain, and<br /> instead stochastic realizations of the lattice model are obtained with kinetic Monte<br /> Carlo simulations.<br /> &lt;p&gt;<br /> In this thesis simpler representations of the master equation are developed for<br /> use in analysis and control. The static map between macroscopic process conditions<br /> and microscopic transition rates is &amp;#64257;rst analyzed. In the limit of fast periodic<br /> process parameters, the surface responds only to the mean transition rates, and,<br /> since the map between process parameters and transition rates is nonlinear, new<br /> effective combinations of transition rates may be generated. These effective rates<br /> are the convex hull of the set of instantaneous rates.<br /> &lt;p&gt;<br /> The map between transition rates and expected film properties is also studied.<br /> The dimension of a master equation can be reduced by eliminating or grouping<br /> con&amp;#64257;gurations, yielding a reduced-order master equation that approximates the<br /> original one. A linear method for identifying the coefficients in a master equation<br /> is then developed, using only simulation data. These concepts are extended to<br /> generate low-order master equations that approximate the dynamic behavior seen<br /> in large Monte Carlo simulations. The models are then used to compute optimal<br /> time-varying process parameters.<br /> &lt;p&gt;<br /> The thesis concludes with an experimental and modeling study of germanium<br /> film growth, using molecular beam epitaxy and reflection high-energy electron<br /> diffraction. Growth under continuous and pulsed flux is compared in experiment,<br /> and physical parameters for the lattice model are extracted. The pulsing accessible<br /> in the experiment does not trigger a change in growth mode, which is consistent<br /> with the Monte Carlo simulations. The simulations are then used to suggest other<br /> growth strategies to produce rougher or smoother surfaces.<br /> | flags = <br /> | filetype = PDF<br /> | filesize = 3070K<br /> | tag = mag02-phd<br /> | id = 2002<br /> }}</div>

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