COLL 475 |
| John E. Crowell and Lucio D. Flores. Department of Chemistry & Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0314 |
| Quasi-real time in-situ infrared spectroscopy has been utilized to study the chemical boundary layer (CBL) region formed during atmospheric pressure chemical vapor deposition (APCVD) of dielectric thin films. Emphasis will be given to the deposition of doped and undoped silicate glass using the reaction between tetraethoxysilane (TEOS) and ozone, and dopants such as trimethylborate (TMB) and trimethylphosphite (TMPi). The CBL-FT-IR methodology provides direct chemical measurement of the gas phase deposition intermediates formed allowing for measurement of both film forming precursors and film formation processes. Similarly, CBL difference spectroscopy (CBL-DS) provides a sensitive measurement of the time needed for attainment of steady state reactor conditions after introduction or switching of reagents. Partial least squares Beer’s law quantitative methods applied to the isolated form of ethoxysilanol show that its concentration is reduced by a factor of ca. two during growth of PSG under steady state conditions. We have developed a PLS methodology to quantitate reactive chemical mixtures of TEOS and ozone and found the chemical kinetics to be independent of added phosphite. The enhancement in deposition rate observed upon phosphorus addition along with the measured reduction in gas phase isolated silanol groups illustrates that gas phase ethoxysilanol species are the main film deposition intermediates in equilibrium with SiO2 film growth. This result shows that real time CBL-DS is a powerful methodology to determine the chemical mechanisms of film growth as well as the associated chemical kinetics of gas phase processes responsible for their growth. Comparisons will be made of the intermediates and reaction processes active during growth of doped silicate glasses with different dopants (i.e. during growth of PSG, BSG, and BPSG thin films). |
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Vibrational Analyses of Dry and Wet Surfaces
8:30 AM-11:30 AM, Thursday, April 1, 2004 Marriott -- Grand Ballroom H, Oral
Division of Colloid and Surface Chemistry |