Gas barrier properties of silicon oxide films prepared by plasma-enhanced CVD using tetramethoxysilane

Abstract

Silicon oxide films were deposited by means of capacitively coupled RF plasma-enhanced CVD using a mixture of tetramethoxysilane and oxygen as source. Chemical compositions and bonding states of the deposited films were analyzed by FTIR and XPS. The absorption bands due to Si–CH 3, Si–H and Si–OH in the FTIR spectra became markedly smaller when the RF power and the fraction of oxygen increased and the total pressure decreased. The optimal oxygen fraction, RF power and total pressure were 50%, 200 W and 10 Pa, respectively, for obtaining pure silicon oxide films. In the films deposited under these optimal deposition conditions, the impurities contaminated from the raw organosilane compound were rarely detectable. Oxygen transmittance of the silicon oxide films greatly depended on their thicknesses and compositions. The oxygen transmission rate of the film prepared under the optimal deposition conditions was 1.3 cm 3/m 2 day atm, far <2 cm 3/m 2 day atm, which satisfies the requirements for industrial products in the field of packaging.