We report a stable Cu-based contact stack to overcome Cu diffusion and oxidation problems encountered during the high dielectric constant oxide thin-film device integration. Our Si/SiO2/TaN/Cu(ReNx) contact stack is also beneficial from the barrierless scheme for improving the BaTiO3 thin-film device performance. Interfacial investigation reveals no extensive interaction between BaTiO3 and barrierless Cu contact stack after annealing up to 873 K. BaTiO3 on the low resistivity (4.5 mu Omega cm) Cu-based contact stack behaves fairly similar to that on the Pt counterpart as the symmetry of the leakage current is obtained using different work function contacts (Cu and Pt). As Cu is compatible with integrated circuit processing, our barrierless Cu(ReNx)/BaTiO3 contact stack is readily applicable for integration with Si-based devices. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3242360]