On the Role of the Carrier Gas in the Deposition of Cadmium Telluride

Abstract

Helium and nitrogen were substituted for hydrogen as a carrier gas in the thermally activated organometallic vapor phase epi-taxy of cadmium telluride. The deposition rate decreased markedly and the decrease depended on the particular gas (helium or nitrogen), tellurium precursor (diethyltellurium or diisopropyltellurium), and crystal orientation of the cadmium telluride substrate. Deposition ceased entirely when helium or nitrogen was substituted for hydrogen, the alkyl was diethyltellurium, and the crystal orientation was (111)ca. The carrier gas used in organometailic vapor phase epitaxy (OMVPE) can affect the kinetics of the deposition process in several ways. The carrier gas changes the momentum, heat, and mass transport characteristics of the mixture of reactants in the reactor simply because physical properties differ from one gas to another. The carrier gas also participates in the deposition chemistry (1-3). Mullin and Irvine (1), and Irvine and Mullin (2) exPlored the effect of carrier gas in photo-MOVPE. Jackson (3) reported the effect of hydrogen or helium on th