Reaction Mechanism of Chemical Vapor Deposition Using Tetraethylorthosilicate and Ozone at Atmospheric Pressure

Abstract

The decomposition process of tetraethylorthosilicate (TEOS) and ozone at atmospheric pressure was measured in a closed vessel by in-situ Fourier-transform infrared absorption (FT-IR) analysis, and the changes of the deposition rate and the overall sticking probability β of the film precursor were obtained along the flow direction in a flow-type reactor. It has been found that the film precursors are formed by TEOS decomposition with O-atoms and/or ozone in the gas phase, and that CH 3 CHO may be the first product, followed by the oxidation to CO 2 and H 2 O via HCHO. It is also shown that the film quality changes along the flow direction, that is, O-H bonds in the film decrease and the β-value increases as the reaction proceeds. These results may show that there are several kinds of precursors, and the sticky (unstable) precursors become dominant in the later stages.