First-principles study on electronic structure of Si/SiO2 interface-Effect of interface defects on local charge density

We present theoretical study on the electronic structures of the interfaces between Si substrate and SiO2 under zero bias and when a bias of −1.0 V is applied to the substrate by the first-principle calculation based on real-space finite-difference approach. By comparing the density of states at the interfaces, we study the effect of the defects around the interface on the channel and leakage currents. In addition, the leakage current through the interfaces are examined. Our results indicate that the defects around the interface lead drastic change of the electronic structure of the interface under the electric field and enhance the leakage current through the SiO2 films.