Significant reduction of leakage current in the TiO2/Si structure by the insertion of the CeO2 intermediate layer

The insertion of the CeO2 intermediate layer between the TiO2 layer and the Si substrate reduced the leakage current significantly after rapid thermal annealing (RTA) in O-2 ambient for 3 min. After RTA, the TiO2/CeO2/Si structure showed a significantly lower leakage current than the TiO2/Si structure. At a proper voltage of -2 V, which was defined as the difference between the applied gate bias and the flatband voltage, the leakage current density of the TiO2/CeO2/Si structure was similar to 10(-8) A/cm(2), while the leakage current density of the TiO2/Si sample was similar to 10(-2) A/cm(2). The formation of the intermixed structure of TiO2 and CeO2 at the TiO2/CeO2 interface by RTA was thought to contribute to the reduction of the leakage current. (C) 2000 American Institute of Physics. [S0003-6951(00)00331-4].