Degradation behavior of Ta2O5 stacks and its dependence on the gate electrode

Response of 8 nm Ta2O5 stacks with Al and Au gate electrodes to voltage stress at room temperature and at 100 °C is investigated. Stress-induced leakage current (SILC) reveals significant gate dependence and distinct difference to SILC in SiO2. The mechanisms for SILC generation and stress degradation are discussed. Unlike SiO2, pre-existing traps and positive charge build-up are recognized as a key factor for generation of SILC in Ta2O5 stacks.