The quality of these devices depends strongly on the uniformity in thickness and composition of the film structure. These, in turn, depend on gas flow, thermodynamics and mass transfer in the deposition chamber reactor. Thus, recently, much attention has been given to the area of modeling and numerical simulation studies for gas flow motions in reactors of various geometries. The transport phenomena is described by gas-dynamic equations (conservation of mass, momentum and energy) including species diffusion. These equations are nonlinear partial differential equations and require a tremendous amount of computer resources. CRSC efforts, in addition to the modeling of the deposition process, involves the application of optimization and control techniques with a goal to improve the growth processes. High performance computers such as supercomputers and parallel computers will be utilized. A unique feature of this work is that it brings together the theory, computation and experiment.
CRSC research on control of HPVT reactors is related to the emerging field of ``smart'' material structures such as piezoceramic embedded composite materials. These smart materials are capable of both distributed sensing and actuation and in the context of this research might be employed to control flow motions in the reactor cavity via control of the boundary layers as well as in other structural estimation and control applications.
CRSC researchers on this project include H. T. Banks, K. Ito, G. Kepler, I. Lauko, J. S. Scroggs and H. T. Tran; and the research involves a major interdisciplinary collaborative effort with K. Bachmann and his team of researchers in the Department of Materials Science and Engineering, and N. Dietz and students in the Physics Department.