Growth and properties of epitaxial rare-earth scandate thin films
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- Heeg, T., Schubert, J., Buchal, C. et al. Appl. Phys. A (2006) 83: 103. doi:10.1007/s00339-005-3463-2
Epitaxial rare-earth scandate thin films of 100–1500 nm in thickness have been prepared by pulsed laser deposition on SrTiO3(100) and MgO(100) substrates. Stoichiometry and crystallinity were investigated by Rutherford backscattering spectrometry/channelling (RBS/C), transmission electron microscopy, and X-ray diffraction. Electrical measurements on microstructured capacitors with a SrRuO3 bottom electrode and Au top contacts reveal dielectric constants of 20 to 27, leakage currents of 0.85 to 6 μA/cm2 at 250 kV/cm, and breakdown fields of 0.6 to 1.2 MV/cm. The optical bandgaps of the films range from 5.5 to 6 eV. The results substantiate the high potential of rare-earth scandates as alternative gate oxides.