Study of atmospheric pressure chemical vapor deposition by using a double discharge system for SiOx thin-film deposition with a HMDS/Ar/He/O2 gas mixture

SiOx thin films were deposited at atmospheric pressure by using a double discharge system composed of a remote-type dielectric barrier discharge (DBD) formed above the substrate and a direct-type DBD formed by applying an AC power to the substrate with a gas mixture of hexamethyldisilazane (HMDS)/O2/He/Ar. Instead of using a single DBD, the use of the double discharge system not only showed higher SiOx thin film deposition rates but also produced fewer impurities in the deposited SiOx thin film. The improvement was partially related to the increased gas dissociation near the substrate through the direct-type DBD and to the remote-type DBD. A 7-kV, 30-kHz AC voltage was applied to the remote-type DBD and a 5-kV, 20-kHz AC voltage was applied to the direct-type DBD, with a gas mixture of HMDS (400 sccm)/O2 (20 slm)/He (5 slm)/Ar (3 slm). As a result, a SiOx deposition rate of 58.29 nm/scan could be obtained while moving the substrate at a speed of 0.25 meter/min.