LOW TEMPERATURE MATRIX ISOLATION SPECTROSCOPIC STUDIES OF UNSTABLE PRECURSORS OF GROUP III-NITRIDE FILMS
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Date
1997
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Publisher
Ohio State University
Abstract
The generation of Group III metal-nitride thin films following the photolysis or thermolysis of the corresponding Group III metal triazide has been demonstrated. These films are of considerable practical interest to the semiconductor industry. The matrix isolation studies presented here were initiated to probe the mechanism of the formation of the Group III triazid and to understand to photolysis process leading to the nitride. The boron triazide studies will be emphasized. $B(N_{3})_{3}$ is prepared by mixing $HN_{3}$, with $BCl_{3}$, in a 3:1 ratio. The product is not stable, so a flow system which allows $HN_{3}$ and $B(N_{3})_{3}$ each diluted to 1% Ar to mix was coupled with our matrix isolation apparatus. $B(N_{3})_{3}$ was isolated in a low temperature matrix using this method. The intermediates, $BCl_{2}N_{3}$ and $BCl(N_{3})_{3}$, should in principle, be generated by adjusting the stoichiometric mixing ratio of $HN_{3}$ and $BCl_{3}$ to 1:1 and 2:1, respectively. The 1:1 mixing ratio did produce $BCl_{2}N_{3}$ and detailed IR matrix spectra assigned on the basis of observed isotope shifts and of comparison with Gaussian 94 predictions will be presented $BCl(N_{3})_{3}$ has proven to be more difficult, possibly because of its stability relative to $BCl_{2}N_{3}$, and $B(N_{3})_{3}$, and its stability is being examined via Gaussian94 calculations. The second aspect of this study is the photolysis mechanism by which the Group III triazide decomposes to form a nitride film. Low temperature matrices of $B(N_{3})_{3}$ are photolyzed at 230 and FTIR is used to monitor photolysis process. The results of these experiments will be presented and discussed.
Description
Author Institution: Department of Chemistry \& Biochemistry, University of Denver