Band gap enhancement and electrical properties of La2O3 films doped with Y2O3 as high-k gate insulators

In this study, we prepare the well crystallized La2O3 films by doping Y2O3 with different contents (La2-xYxO3) and examine the dielectric and electrical properties of La2-xYxO3 films experimentally. It is found that the optical band gap of La2-xYxO3 film increases with the increase in Y content (x) monotonically. Furthermore, a low leakage current of about 10(-5) A/cm(2) (equivalent oxide thickness: 1 nm) when the gate voltage is 1 V larger than the flat band voltage, and good capacitance-voltage characteristics in Au/La2-xYxO3/Si metal-insulator-semiconductor capacitors are observed. Our results also indicate that Pt/La2-xYxO3/Au metal-insulator-metal capacitor shows a low leakage current and a small voltage dependence of the capacitance.