Modeling of Post Soft Breakdown Conduction through Ultrathin High-k Gate Dielectrics

A Quantum Mechanical model is presented to describe the post Soft Breakdown (SBD) phenomena for MOS structure with ultrathin high-k gate dielectrics. We model the SBD event by considering a lowered barrier height at the SBD spot area. The current density through fresh stack gate oxide area and the SBD area are evaluated using a Quantum Mechanical Wave Impedance method. Simulated results for post SBD current with the reported experimental data reveal good agreement and hence important SBD parameters such as barrier height, carrier effective mass, SBD spot area and imaginary potential are extracted.