Impact of oxygen supply during growth on the electrical properties of crystalline Gd2O3 thin films on Si(001)

We investigated the influence of additional oxygen supply and temperature during the growth of thin Gd2O3 layers on Si(001) with molecular beam epitaxy. Additional oxygen supply during growth improves the dielectric properties significantly; however, too high oxygen partial pressures lead to an increase in the lower permittivity interfacial layer thickness. The growth temperature mainly influences the dielectric gate stack properties due to changes of the Gd2O3/Si interface structure. Optimized conditions (600 degrees C and p(O2)=5x10(-7) mbar) were found to achieve equivalent oxide thickness values below 1 nm accompanied by leakage current densities below 1 mA/cm(2) at 1 V.