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Microwave enhanced chemical vapor deposition of silicon compound thin films and their characterization

by Gopal, Madan

Abstract (Summary)
This project involves the study of deposition of silicon compound films using 3 different liquid reactants, namely, tetramethyl silane (TMS), silicon tetrachloride (STC), and hexamethyl disilazane (HMDS), all saturated in nitrogen. The films were characterized with respect to their composition, thickness, structure, and oxidation resistance. The influence of process variables, namely, pressure, deposition geometry, and reactant flow rate/ratio, on the film properties were determined. The effect of annealing on the film thickness and composition was determined. An effort was made to modify the composition by exposing the substrates to a nitrogen plasma for 1 minute before film deposition. The results show major interactions between the pressure, flow rate, and flow geometry in the system. The results seem to be the net effect of gas phase concentration, dissociation, diffusion, and residence time distribution. These were in turn governed by the silicon source compound used. For TMS reactant entry length of 4 inches was optimum. The major constituents of the film were Si, N, O, C, and H. In films produced with STC, chlorine was also detected. The process variables did not influence the composition of the film. The proportion of Si/N was between 0.75 and 1.33. IR spectra show SiCH 3, SiO, SiNH, and SiN bonds. Nitrogen plasma pre-exposure did not affect the film composition but altered the deposition characteristics. Annealing changed the films essentially to SiO 2and reduced film thickness. The films exhibited good oxidation properties.
Bibliographical Information:

Advisor:

School:Ohio University

School Location:USA - Ohio

Source Type:Master's Thesis

Keywords:microwave enhanced chemical vapor deposition silicon compound thin films characterization

ISBN:

Date of Publication:01/01/1991

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