The effect of thickness and temperature on dielectric properties of lutetium oxide thin films grown by electron-beam deposition on quartz

Abstract

Lutetium oxide films (Lu2O3) of different thicknesses (d=47–546nm) were prepared by physical vapor deposition method with an electron-beam gun. The dielectric properties of Lu2O3 films were examined in metal/insulator/metal-type structures. The influence of the temperature (T=300–500K) and the frequency (f=0.1mHz–3MHz) on dielectric properties was examined. At room temperature, the structures exhibited high capacitance density of 0.2–2fF/μm2. Thick, as-deposited, films were characterized by the dielectric permittivity of 12.9, whereas for films thermally annealed the permittivity was 11.1. For films thinner than 120nm the permittivity decreased down to κ=9.6. This effect was caused by thin near-electrode layers at both metal/insulator boundaries. Effective capacitance of these two near-electrode regions was 20.7fF/μm2, as determined from the capacitance–temperature characteristics.