Interaction of Ir and IrO2 thin films with polysilicon, W and WSIx.

Ir and IrO2 thin films have been identified as potential electrode materials for ferroelectric capacitors. These electrodes have shown excellent electrical characteristics. The integration of ferroelectric capacitors into memory cells requires the bottom electrode material to be placed directly over a contact plug. This paper studies the interaction of Ir and IrO2 with commonly used plug materials such as polysilicon, tungsten (W), and tungsten silicide (WSix) after a post-deposition annealing at 800 degrees C. Film properties such as composition, resistivity, crystallinity, adhesion, and micro-structure have been examined before and after anneal. The results show that W is a possible plug material for Ir electrode; while polysilicon and WSix are potential candidates if IrO2 electrodes are used.