Bis(bis(trimethylsilyl)methyl)tin(IV) chalcogenides as possible precursors for the metal organic chemical vapor deposition of tin(II) selenide and tin(II) telluride films

Two air- and light-stable compounds, bis(bi s(trimethylsilyl)methyl)tin(TV) selenide and telluride, [Sn{(SiMe3)(2)CH}(2)(mu-E)](2) (E = Se (1) and Te (2)), were investigated as possible precursors for metal organic chemical vapor deposition(MOCVD). Their sublimation rate was measured by thermal gravimetric analysis in the 190-260 degrees C range and was found to be as high as 2 mg/min at 260 degrees C at 14 mbar. MOCVD experiments were conducted using both compounds as precursors at 300-600 degrees C and 1 Torr under a flow of a 1:1 He/H-2 mixture. Strong selectivity of the decomposition reaction was found toward the metallic surfaces (copper, silver, gold) with respect to nonmetallic surfaces (quartz, silicon with natural oxide layer). A thin layer (approximate to 10 nm) of conducting seeding layer was used for the deposition of carbon-free film of SnTe, using 2 as a precursor. The films were examined by scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy analyses.