Synthesis of local epitaxial α -(Cr_(1-x)Al_X)_2O_3 thin films (0.08 ≤ x ≤ 0.16) on α-Al_2O_3 substrates by r.f. magnetron sputtering

摘要

Abstract(0001) oriented nanocrystalline α-(Cr1-xAlx)2O3(0.08≤x≤0.16) thin films with an average thickness of ~270nm were grown onc-plane α-Al2O3(0001) single crystal substrates at 400°C by non-reactive r.f. magnetron sputtering by a combinational approach using a segmented ceramic target. The stoichiometric composition of the films was determined by electron probe micro-analysis (EPMA). The composition dependent crystallization behavior of the α-(Cr1−xAlx)2O3thin films was characterized by detailed X-ray diffraction (XRD) analyses (i.e. XRD in Bragg-Brentano geometry, Rocking curve, Pole figure, Reciprocal space mapping (RSM)). Transmission electron microscopy (TEM) was carried out to study the microstructure and describe the orientation and epitaxial relationship between the films and the substrates. Further, Raman spectra show a significant shift of phonon frequency with Al concentration.Highlights•(0001) α-(Cr1−xAlx)2O3thin films were grown on (0001) α-Al2O3substrates at 400°C.•The epitaxial relationship is [0001]f//[0001]sand [101¯0]f//[101¯0]s.•The lattice parameters and epitaxial quality are dependent on the Al concentration.•Raman spectra show a shift of phonon frequency with the Al concentration.