Degradation behavior of Ta_2O_5 stacks and its dependence on the gate electrode

摘要

Response of 8 nm Ta_2O_5 stacks with Al and Au gate electrodes to voltage stress at room temperature and at 100 ℃ is investigated. Stress-induced leakage current (SILC) reveals significant gate dependence and distinct difference to SILC in SiO_2. The mechanisms for SILC generation and stress degradation are discussed. Unlike SiO_2, pre-existing traps and positive charge build-up are recognized as a key factor for generation of SILC in Ta_2O_5 stacks.