SPECTROSCOPIC INVESTIGATIONS OF GAS-PHASE CHEMISTRY DURING LASER-INDUCED PHOTOLYTIC CVD OF W

Photolytic reactions, induced by irradiating gas mixtures containing WF6 with an ArF excimer laser beam, have been investigated. For an unfocused laser beam (PHI almost-equal-to 0.1 J/cm2) a spectrum characteristic of chemiluminescence was obtained, provided that all the components Ar, H-2 and WF6 were present in the vapour. By increasing the temperature the chemiluminescence ceased. For the focused beam conditions (PHI almost-equal-to 1-2 J/cm2) an emission spectrum characteristic of elemental tungsten was observed. For the same WF6 and H-2 partial pressures but with Ar in the vapour much higher intensities of the tungsten peaks were obtained than when only WF6 or WF6/H-2 were used.