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Rate, crystallinity and phase purity of vapor-grown diamond deposits are discussed. Emphasis is on microwave plasma CVD of diamond from C/H-, C/H/O-, C/H/F-, C/H/CI- and C/H/N-gas mixtures.The manufacture of wear-resistant diamond thin films, diamond vacuum window membranes and thick diamond heat spreader plates are used as examples to outline the influence of various deposition parameters on the performance of finished products and to describe the use of ternary gas phase compositional diagrams as tools for minimization of deposition technology and product optimization efforts.

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Silica layers doped with fluorine have been deposited inside a quartz glass tube from a SiCl4/SiF4/O2 gas mixture. The oxidation reaction was initiated by a nonisothermal microwave plasma maintained at pressures of about 10 Torr and wall temperatures in the region of 1000°–1100°C. From the experiments it was found that fluorine was incorporated in the silica deposit, producing layers with a lower refractive index than that of pure silica. Although the reaction to form SiO2 from a SiF4/O2 gas mixture is different from that with SiCl4/O2 , the efficiency of the deposition reaction with SiCl4/SiF4/O2 is comparable to that with SiCl4/O2 .

SM and GI fibers have been prepared by the low-pressure PCVD process using fluorine as the main dopant and small amounts of GeO, as codopant. Compared to pure fluorine doping, these fibers showed markedly improved optical properties. High N.A. (A = 2 percent) GI fibers with Rayleigh scattering losses as low as 1.0 dB p n 4 / km as well as "deeply depressed cladding" SM fibers with scattering coefficients of 0.85 dB pm4/km have been prepared. Simultaneously, a reduced sensitivity of the optical losses on the drawing conditions and improved mechanical properties have been observed.