KINETIC AND MECHANISTIC STUDY OF THE CHEMICAL-VAPOR-DEPOSITION OF TITANIUM-DIOXIDE THIN-FILMS USING TETRAKIS-(ISOPROPOXO)-TITANIUM(IV)

The mechanism of TiO2 thin film deposition on single crystal TiO2 by c hemical vapor deposition (CVD) using tetrakis(isopropoxo)titanium(IV) (TTIP) has been investigated. The structure of the rutile(100) surface has been shown to form a 1 X 3 reconstruction using reflection high-e nergy electron diffraction. Temperature programmed reaction spectrosco py and molecular beam scattering have been employed to probe the kinet ics of the reaction of TTIP and to identify reaction products. The dep osition mechanism involves two parallel pathways to form TiO2: at lowe r temperatures (500-650 K) propene and isopropanol are formed as produ cts; at higher temperatures (>650 K) propene and water are formed as p roducts in a second pathway that becomes dominant. An activation energ y of 57 +/- 8 kJ/mol has been measured for the first pathway. The resu lts for the single crystal surface are compared to earlier work on pol ycrystalline substrates.