Project Title:

Microscopic and Macroscopic Modeling of Layer Growth Kinetics and Morphology in Vapor

92-1-15.01-6576                                                   NAS03-26838
Microscopic and Macroscopic Modeling of Layer
     Growth Kinetics and Morphology in Vapor
Deposition Processing
CFD Research Corporation
3325-D Triana Boulevard
Huntsville, AL  35805
Anantha Krishnan                                     (205-536-6576)

Abstract:

     Physical or chemical vapor deposition processes are used
increasingly to obtain solid films on substrates. Thin films grow
through the adsorption of molecular species which undergo a host
of surface kinetic processes, including diffusion, reaction, and
nucleation, before they form the new solid. Depending on the
specific interactions occurring on the surface, the resulting film
morphologies range from molecularly smooth to incomplete coverage
with dendritic habit. Many device applications require films that
are rather smooth on a molecular level. Hence, an understanding of
the conditions governing the growth of specific film morphologies
is important for efficient design of vapor deposition processes.
Current process modeling, however, deals almost exclusively with
the macroscopic transport aspects of vapor deposition. This
project involves the development of a Monte Carlo (stochastic)
model to simulate the microscopic surface phenomena (of vapor
growth kinetics and morphology) and the coupling of this
microscopic model with an advanced macroscopic transport and
reaction model. The microscopic model to be developed in Phase I
will elucidate the dependence of film morphology on the energy
parameters, temperature, and interfacial supersaturation. In Phase
II, the microscopic model will be incorporated into an existing,
advanced macroscopic fluid-flow code and validated against
experimental data.

Potential Commercial Application:

Potential Commercial Applications:  The development of a realistic
model for the evolution of interfacial vapor growth morphologies
will lead to a better understanding of the factors affecting the
growth of thin films. This model, after coupling with the selected
computational fluid dynamics (CFD) code, can be used to simulate
film growth under various conditions, including microgravity.

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