Tunneling properties of ultra-thin SiO$_2$ barriers: a first-principles study

We performed first-principles simulations of the electron tunneling through ultra-thin SiO$_2$ barriers in Si(100)/SiO$_2 $/Si(100) structures. The atomic structures of the Si/SiO$_2$ interfaces are generated by considering various silicon suboxide states observed in photoemission studies. For comparison, we also consider sharp Si/SiO$_2$ interfaces with dangling bonds. For each atomic structure, the tunneling conductance is calculated by a first-principles scattering-state method based on the {\em ab-initio} pseudopotentials and the density functional theory within the local density approximation. As a result we obtained the dependence of the tunneling probabilities on the oxide thickness and on the interfacial structures. Effects of the dangling bonds on the tunneling probabilities will also be discussed. Computational resource for this work is provided by KISTI under the 8th Strategic Supercomputing Support Program.