Structural and Thermal Properties of Single Crystalline Epitaxial Gd₂O₃and Er₂O₃Grown on Si(111)

Abstract

Lattice mismatch with a substrate and difference in coefficient of thermal expansion to the substrate induces stress and deformations in crystalline structure of epitaxially grown layers. In this work, we present results of structural study of gadolinium oxide and erbium oxide grown on silicon (111) substrate applying X-ray diffraction at room temperature and during in-situ heating up to 1273 K. The layers are almost fully relaxed at room temperature. Only minor tetragonal distortion of the crystal lattice was indirectly detected. No thermal induced stress relaxation occurs in the oxide layer during the in-situ heating and cooling procedure though strong tetragonal distortion of the oxide lattice due to thermal expansion difference with silicon. The time-domain thermo-reflectance measurements reveal that thermal conductivity of the rare earth oxides is approximately five times higher than that of silicon dioxide.