AbstractGe-Sb-Te (GST) thin films were deposited by chemical vapor deposition (CVD) and hot-wire chemical vapor deposition (HW CVD). Several precursor sets (tetraethylgermanium - trimethylantimony - dimethyltellurium (TEGe-TMSb-DMTe), tetraisopropylgermanium - triisopropylantimony - di-tertiarybutyltellurium (TiPGe-TiPSb-DtBTe) and tetraallylgermanium - triisopropylantimony - diisopropyltellurium (TAGe-TiPSb-DiPTe)) were tested for CVD. For the TEGe-TMSb-DMTe precursor set tellurium and germanium could be detected in the films for all deposition temperatures investigated, while Sb was found only in the films deposited at elevated temperature higher than 550 °C. The deposition temperature could be reduced by using two other precursor sets (TiPGe-TiPSb-DtBTe and TAGe-TiPSb-DiPTe). The Ge content, however, could not be sufficiently increased to obtain stoichiometric Ge2Sb2Te5 films. Therefore, the hot wire or catalytic method was applied to improve the decomposition of the precursors. In this case, the desired composition (e.g. Ge2Sb2Te5) was obtained at each investigated temperature by adjusting dosing and deposition parameters. Additionally, film roughness (as low as 2 nm) and deposition rates could be optimized by adjusting deposition temperature and pressure.
Directional crystallization of C8-BTBT-C8 thin films in a temperature gradient
