Charge transport mechanism of stress induced leakage current in thermal silicon oxide

摘要

The charge transport mechanism of electron via traps in thermal SiO_2 has been studied. Electron transport is limited by phonon-assisted tunneling between traps. Thermal and optical trap energies are W_t = 1.6 eV and W_(opt) = 3.2 eV, respectively. Charge flowing leads to oxygen vacancies generation, and the leakage current increases. Long-time annealing at high temperatures decreased the leakage current to initial values due to oxygen vacancies recombination with interstitial oxygen. Taking into account results of ab initio simulations we found that the oxygen vacancies act as electron traps in SiO_2.