Indirect tunneling in metal-insulator-metal junctions

I - V characteristics of realistic MIM junctions were calculated assuming a two step indirect tunneling as the major mechanism. Electron-phonon broadening of the energy level of the intermediate defect states is taken into account. The theory is compared with our experimental investigations of Pd-MgO-Pd junctions and good quantitative agreement is achieved. The intermediate states are provided by the F-centers of the MgO vacancies. A consistency between the experimental data and the theory is obtained for the values of the physical parameters known from independent studies on MgO.