DC triode sputtering deposition and characterization of N-rich copper nitride thin films: Role of chemical composition

(N-rich) Cu3N polycrystalline films were deposited by DC triode sputtering from a copper target in a mixture of argon and nitrogen atmosphere. Their chemical composition, structure and electrical properties have been studied as a function of deposition parameters: nitrogen partial pressure (P-N2) and DC bias. Depending on P-N2 and DC bias. the atomic nitrogen incorporated into the layers ranges from 26 at% to a limit value of 33 at% as measured by ion beam analysis (IBA) techniques. X-ray diffraction (XRD) data show that most of the layers are single phase, polycrystalline and with preferential < 1 0 0 > orientation. Optical and electrical measurements indicate that all layers present intrinsic semiconductor behavior with a thermal gap around 0.21-0.25 eV and a direct optical gap between 1.5 and 1.7 eV. The physical properties observed for these films are discussed in relation to nitrogen contents and sputtering parameters. (C) 2008 Elsevier B.V. All rights reserved.