Reaction Chemistry of ZnTe Metalorganic Vapor-Phase Epitaxy
摘要:
The reaction chemistry of zinc telluride (ZnTe) metalorganic vapor-phase epitaxy (MOVPE) from dimethylzinc (DMZn), diethylzinc (DEZn), and diisopropyltelluride (DIPTe) has been studied using on-line gas chromatography and infrared spectroscopy. Two growth regimes have been discovered: one at low values of the II/VI ratio and the other at higher values of the II/VI ratio. In the first regime, the group VI compound is consumed in excess, while in the second regime, the group II compound is consumed in excess. The crossover point lies at II/VI = 5.0 for DMZn and at II/VI = 0.3 for DEZn. Stoichiometric ZnTe is deposited under all growth conditions. The excess DIPTe consumed is converted into volatile diisopropylditelluride and isopropyltellurol. Conversely, the excess DEZn or DMZn consumed produces zinc metal. These waste byproducts accumulate in the outlet of the reactor. The hydrocarbon products generated from the ethyl and isopropyl ligands are indicative of radical disproportionation, recombination, and hydrogenation reactions. However, the methyl ligands mainly undergo surface hydrogenation to produce methane.
The feasibility of InSbTe chalcogenide materials prepared by metallorganic chemical vapor deposition (MOCVD) for phase-change memory (PRAM) applications was demonstrated. Filmsgrown below 225°C exhibited an amorphous structure, and the filmsgrown at 300°C included various crystalline phases such as In-Sb-Te, In―Sb, In-Te, and Sb-Te. The composition of the amorphous filmsgrown at 225°C was dependent
Synthetic routes to alkylvinyl tellurides by direct reaction of metallic tellurium, acetylene and alkyl halide in the system KOH-SnCl2-H2O and successive interaction of divinyl telluride with lithium and alkyl halide in liquid ammonia have been developed.