Structure and electrical properties of CdIn2O4 thin films sputtered at elevated substrate temperatures

A Hall mobility as high as 39.4 cm2 V−1 s−1 was obtained for cadmium indate (CdIn2O4) thin films deposited by rf reactive sputtering from a Cd–In alloy target. The structural and electrical properties for both as-sputtered and after-annealed thin films were studied as a function of the substrate temperatures. The results revealed that elevated substrate temperatures favour the formation of CdIn2O4 thin films with spinel phase. The electrical properties can be understood by a combination of the occupancy of In cations on the tetrahedral vacancies in the spinel unit cell at the elevated substrate temperatures and the formation of oxygen vacancies originating from off-stoichiometry. It can be inferred that the presence of secondary phases in the CdIn2O4 thin films deposited in an oxygen-deficient atmosphere is responsible for their electrical properties. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)