Effects of thermal treatment on structural and electrical properties of sputtered Ir-W alloy thin films

Thermally and chemically stable electrode films are required for capacitor electrodes of semiconductor memories, such as dynamic random access memories (DRAMs) and ferroelectric random access memories (FeRAMs). In this study, iridium-tungsten (Ir-W) alloy thin films were prepared on SiO2/Si substrates by RF magnetron sputtering, and the effects of thermal treatment in oxygen atmosphere on the structural and electrical properties of the films were studied. The surface of the as-deposited Ir-W films was very smooth and the films showed low electrical resistivities below 120 μΩ cm. The resistances and the smooth surface morphology of the Ir-W (approximately 20 at.%) films remained after thermal treatment up to 600 °C in oxygen, which indicates the high thermal stability of the Ir-W alloy thin films.