Field Dependent Electrical Conduction in TiN/HfO_2/SiO_2/P-Si (nMOS) Capacitor for Before and After Stressing

摘要

In summary, it is observed that Poole-Frenkel is the dominant conduction mechanism in the high field region where as Ohmic conduction is the dominant mechanism in the low field region for substrate injection for both before stressing and after stressing. Negatively charged oxygen vacancies (VAT) are contributing to the Poole-Frenkel conduction mechanism. Similar conduction mechanisms are observed for high temperature stressing as observed for low temperature stressing as well as fresh devices. V" is the active defect for electrical conduction process through the gate stack for room temperature stressing where as V" is the active defect for high temperature stressing. The observed high gate leakage current in high temperature stressed devices in comparison to room temperature stressed devices is due to the generation of new oxide defects in the high-k layer and high trap density.