Mechanism of gate dielectric degradation by hydrogen migration from the cathode interface

Hydrogen migration in a SiO2/Si system is examined in detail by nuclear reaction analysis. Electrical reliability measurements reveal a correlation between hydrogen migration from the cathode interface to the SiO2/Si interface and dynamic degradation of the gate dielectric. In addition, the defect levels generated in the bulk of SiO2 have an energy distribution corresponding to that of oxygen vacancies, as revealed by comparing the measured and simulated stress-induced leakage current. Finally, a model of hydrogen-induced gate dielectric degradation is proposed based on first-principles calculations.