Deposition of Plasma Polymer Films by an Atmospheric Pressure Glow Discharge

Plasma assisted chemical vapor deposition is a proven method for the formation of thin films. The application of non-thermal low pressure plasmas containing organic compounds for thin film deposition by plasma polymerization is well known1. These films are successfully applied for corrosion protection and as diffusion barriers2. Operating non thermal discharges under atmospheric pressure conditions requires no vacuum devices, therefore the integration of the plasma process into production lines is greatly simplified. Batch processing can be avoided thus reducing production costs significantly. The plasma of the atmospheric pressure dielectric barrier discharge (DBD) has been used for technical applications for many years starting with ozone generation (Siemens, 1852). Other fields of application are flue gas cleaning, surface treatment of polymeric foils and films and thin film deposition3. The dielectric barrier discharge is usually a filamentary one and therefore strongly inhomogeneous. A homogeneous DBD without filaments was described by Okazaki et al. in a planar electrode configuration in He, later also in other gases and gas mixtures4. According to some similarities with the dc glow discharge this discharge is called atmospheric pressure glow discharge5. Its homogeneity favours this discharge for thin film deposition techniques.