Investigation Of Fluorocarbon Films And SiO₂ Films By DBD-PECVD

Plasma deposited fluorocarbon (a-C:F) films have been widely studied because of their remarkable properties, including superhydrophobicity , a low dielectric constant (1.6-2.1) and biocompatibility. Applications for such films include dielectric layers for the ultra-large scale integration devices, biopassivation coatings for implantable devices, and hydrophobic layers on paper.With the micro-electronics technique and the large scale integration of the fast development, the SiO₂ thin film have been widely used in the manufacturing of large scale integration because of its stable chemical properties and electric insulation, So making silicon-oxide thin film become one of the key craft within technique of the integrated circuit manufacturing.And silicon-oxide is high hardness, good wearable, adiabatic, the high rate of light permeation , the strong ability of anti- erosion and low lie electricity property .Dielectric barrier discharges have been successfully used to deposit fluorocarbon (a-C:F) films on various materials, such as paper, glass, and silicon substrates. The primary monomers used for plasma polymerization were octafluorocyclobutane (C4F8), octafluoropropane (C₃F₈), and difluoromethane (CH₂F₂) . a-C:F films were characterized using Fourier transform infrared spectroscopy , scanning electron microscopy , atomic force microscopy and static contact angle measurements . Surface and structural properties of deposited films are strongly dependent on the plasma compositions and discharge pressure. a-C:F films deposited on paper are to enhance its barrier properties and to achieve hydrophobic surfaces. Contact angle studies reveal that a minimum a-C:F film thickness of about 160 nm on paper is required to completely cover surface and near-surface fibers, thereby providing the paper with long term hydrophobic character. In the C3F8 and C4F8 systems, the contact angles of the deposited films do not change appreciably with plasma parameters and are strongly dependent on the substrate roughness. Hydrogenated a-C:F films deposited with CH₂F₂ plasmas show the relatively low contact angles due to the existence of CHx (x=1-3) groups.The deposition of SiO₂ films from low-pressure dielectric barrier discharge plasmas has been investigated using tetraethoxysilane (TEOS)/O₂ as the feed gas. Films were analyzed using Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy, AFM-based nanoindentation/nanowear techniques, and conductive AFM. Film deposition rates and hydrocarbon incorporation in the SiO₂ film decrease with addition of O₂. High-quality SiO₂ films with extremely low surface roughness are deposited at high oxidant concertrations. The SiO₂ films deposited with TEOS/O₂ plasmas were found to have soft surface layers, 0.5-1.5 nm thick, which contribute to an improvement of their field emission properties. The conductive surface layer with a relatively high carbon concentration can be formed during the interactions between the energetic ions and the growing film surface.