CVD of metal chalcogenide films

Abstract
The preparation of SnE, Ag₂E and Cu₂E (E = Se, Te) thin films by Chemical Vapor Deposition (CVD) and Vapor Phase Transport (VPT) has been studied. The precursors, [Sn{(SiMe₃)₂CH}₂(µ-E)]₂ (E = Te, Se), have been studied for the deposition of SnE films. Deposition experiments have been performed on nonmetallic substrates, Si, and SiO₂, as well as on Cu and on M/Si and M/SiO₂ substrates (M = Cu, Ag and Au). Depositions were carried out at temperatures ranging between 300 - 600° C and pressures ranging between 0.5 - 40 mbar in either pure H₂ atmosphere or H₂/He mixture in a cold wall vertical CVD reactor. The film deposition was very selective with respect to the metal substrates, where phases of M₂E and MSn were found. Thin metal film was employed as a seeding layer to obtain SnTe films. Thin films of chalcogenides M₂E (M = Ag, Cu and E = Se, Te) were prepared by vapor transport and electron beam evaporation techniques. The magnetoresistivity (MR) of Ag_2-δ showed markedly different temperature dependencies for oriented and non-oriented films. Furthermore, in contrast to the bulk samples, a large anisotropy and a sign reversal effect of MR, were found in these films.