Cathode Sheath Charge Transfer Effects
Interim rept. 10 Jun 1987-10 Mar 1991
UNITED TECHNOLOGIES RESEARCH CENTER EAST HARTFORD CT
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The United Technologies Research Center, under WL Contract No. F33615-87-C-2718, has carried out a theoretical research investigation of ion- molecule reactions that take place in the sheath region of low pressure discharges in silane gas mixtures. Of particular interest were the dissociative charge transfer mechanisms and energy dependent reaction rates of electrons, H, H-, H3 and several noble gas ions He, Ne, Ar in collisions with silane SiH4. Such reactions are an important component in the modeling of plasma- processing discharges for producing device-quality silicon films and a detailed understanding of their kinetics is required. Similar ion-molecule reactions with methane and other lower alkanes have proven to be of importance in the analysis of hydrocarbon combustion. The results of this theoretical investigation furnish fundamental data and provide a better understanding of the role of ion collision-induced molecular decomposition. The program for the research effort under this contract was formulated into three phases. Phase I consisted of a critical examination of available theoretical methods, including R-matrix methods, that are applicable to the prediction of the rates of dissociative charge transfer in ion-molecule collisions. These studies results in the development of an improved R-matrix code which incorporated analysis of reaction products. Specific attention was given to those methods most applicable to ion collisions with silane SiH4, and to those molecules where estimates of the general applicability and accuracy of the methods could be defined.
- Inorganic Chemistry