Spectroscopic analysis of silica soot deposited by flame hydrolysis deposition

Abstract

Flame hydrolysis deposition is widely used to fabricate SiO2/Si passive optical waveguide devices for optical communication network. In flame hydrolysis deposition, silica soot doped with various elements such as B, P, and Ge is formed in the form of thin film layer and the composition of this layer is not predictable due to complex process variables. In this research, it was intended to clarify the quantitative relationship between simple process parameters and resulting chemical composition. In FHD process, compositional analysis of soot by FTIR and ICP-AES under the control of the amount of dopant is carried out to obtain the compositional information, which will affect the optical and thermo-mechanical properties of films. By measuring absorbance spectra with FTIR, the variation of B-O, Si-O, OH (H2O) composition in FHD soot was investigated and could be quantified in B-O absorbance by ICP-AES analysis.