GLOW DISCHARGE POLYMERISATION

Organometallic compounds were used to fabricate semiconductive thin films on different substrates by glow discharge polymerisation [69]. Tetramethyltin (TMT) and diethylzinc (DEZ) were deposited on several substrates such as polypropylene, Sn02, quartz and glass. The physicochemical properties of the deposited films were characterised by FTIR, XPS, SEM and X-ray diffraction. 

A recent report by Kennedy and Diem describes the promotii effect of a glow discharge (Telsa coil) or ultraviolet irradiation iq)on the low temperature polymerisation of isobutene by titanium tetrachloride. The authors ascribed the yield increases observed to the formation of cocatalytic amounts of chlorine or hydrogen chloride arising from the decomposition of the catalyst into TiCla and a chlorine atom. The interpretation is probably valid, but we point out that HQ is not a cocatalyst for the polymerisation of i )butene by TiCl4 in hexane, one of the solvents used in that work ... 

Fabrication of polymers for these small and integrated sensors should be by the new processing technologies, which can produce accurate, mass reproducible and thin polymers. The polymers fabricated by conventional methods may have potential problems such as the difficulty of preparing thin (<1 pm) and homogeneous films. A plasma-polymerised film offers a new alternative [19]. The plasma-polymerised film is achieved in a glow discharge or plasma in the vapour phase. Such films are thin (< 1 pm), pinhole-free, flat-surface structures and are chemically and mechanically stable. 

Plasma polymers are deposited as a thin film and/or as a powder on surfaces contacting a glow discharge of organic or organometallic feed gases. Plasma polymerisation is a specific type of plasma chemistry, which involves reactions between plasma species, between plasma on the surface [35]. 

Internal electrode reactors have several names, e.g., flat bed, parallel plate, planar, diode, etc. However, this system is rarely used to develop the plasma polymerisation because it breaks the insulation between the electrodes due to polymerisation on the cathode by the dc glow discharge. 

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