CHARACTERIZATION OF CDTE-SB CO-SPUTTERED FILMS

The structure and electrical properties of CdTe-Sb co-sputtered thin f ilms and their relation with composition were studied. The films were grown on glass substrates by radio frequency sputtering deposition. Th e ternary alloys were deposited by co-sputtering of Sb and CdTe. The s ubstrate temperature was varied from room temperature to 250 degrees C . The composition measurements show that the Sb content in the films r anges from 8 to 60 at. %, depending on the area fraction covered by th e Sb attached to the CdTe target. The Sb content is found to be indepe ndent of the substrate temperature. The structure of the films was det ermined from x-ray diffraction measurements. Three kinds of structures were observed, depending on the Sb content and substrate temperature: (1) CdTe polycrystalline films containing small amounts of Sb, that i s probably incorporated in the Cd and Te sites of the CdTe lattice; (2 ) amorphous CdSbTe films, with high Sb content and low substrate tempe ratures; and (3) polycrystalline films composed by a mixture of both S b and CdTe crystallites, with high Sb content and high substrate tempe ratures. The room temperature electrical resistivity of the films vari es from 10(9) Omega cm in the CdTe polycrystalline films to 10(-3) Ome ga cm in the films composed of Sb and CdTe crystallites. (C) American Vacuum Society.