Study of the formation of titanium deposit in the excimer-laser decomposition of titanium tetrachloride by time-resolved UV spectroscopy

Abstract

Time-resolved UV spectroscopy has been used to detect species formed in the laser deposition of titanium from titanium tetrachloride at the entrance window of the reactor. The deposition involves primarily the decomposition of the adsorbed TiCl 4 molecules. The primary decomposition products at low laser fluences are TiCl 3 and chlorine atoms. Chlorine molecules detected in the gas phase close to the surface of the entrance window are formed through recombination of chlorine atoms. Absorption of further photons leads to the splitting off of chlorine atoms from TiCl 3 with the formation of a titanium film. At high laser fluences, titanium atoms and chlorine molecules can be formed directly in a time period of less than 20 ns.