Toward a Unified Theory Correlating Electronic, Thermodynamic and Mechanical Properties at Defective Al/SiO2 Nanodevice Interface: an Application to Dielectric Breakdown

We study the electronic structure and local pressure of Al/crystal-SiO2 (Al/c-SiO2) and Al/amorphous-SiO2 (Al/a-SiO2) interface systems in the presence of oxygen vacancy. In this modeled nanodevice, we created an oxygen vacancy at different sites from the interface to the quasi-bulk SiO2 region in both neutral and charged Al/SiO2 systems. We found that oxygen vacancies close to the interface do not change the band offset or electronic structures. However, oxygen vacancies far away from the interface generate shallow hole trapping states. We also applied the quantum stress density theory to calculate the local hydraulic pressure around each host oxygen atom to be removed for creating an oxygen vacancy. We found a correlation between vacancy formation energy and the oxygen local pressure, which is consistent with the previous study in the bulk a-SiO2. We also found that oxygen atoms close to the interface have ∼0.9 eV lower formation energy and lower local pressure. In addition, charges (−1 e and +1 e) have...