9500817-Engstrom - GOALI ABSTRACT Deposition and growth of thin films represents an enabling technology that impacts a number of existing and emerging industries, including microelectronic and optoelectronic device fabrication. This work will investigate the use of collimated supersonic jets of molecular thin film precursors under conditions of medium to ultrahigh vacuum to grow thin films. Previous work by the principal investigator has demonstrated explicitly that kinetic limitations to epitaxial growth can be overcome by the use of molecules possessing hyperthermal kinetic energies. This work is being extended to a fundamental examination of the connections between the chemical dynamics of the adsorption reaction and the resulting thin film morphology, as well as an explicit, quantitative evaluation of the hypersonic flow field. The studies will be conducted in a supersonic molecular beam growth chamber that has been optimized for thin film growth and evaluation of the hypersonic flow field, the latter including the pertubing effects of the substrate itself. Computational studies of the flow fields will be made employing the direct simulation Monte Carlo (DSMC) approach. These large-scale simulations will be performed on a massively parellel computing platform. Specific materials systems to be investigated include: selective epitaxial growth of silicon; deposition of silicon carbide on silicon; and deposition and growth of carbon-nitride. It is expected that these studies will provide a fundamentally-based pathway for scale-up of the process necessary for eventual commercial applications.
