Study on nanocrystalline Cr2O3 films deposited by arc ion plating: I. composition, morphology, and microstructure analysis

Nanocrystalline Cr₂O₃ thin films were deposited on silicon wafers with (100) orientation by arc ion plating (AIP) technique at various negative bias voltages. By virtue of X-ray diffraction analysis, scanning electron microscope, and high-resolution transmission electron microscope, the influence of substrate bias voltage on the film growth process, microstructure, and characteristics was investigated systematically, including the phase constituents, grain size, lattice constant, chemical compositions, as well as surface and cross-section morphologies. With increasing the bias voltage, the grain size and lattice constant of AIP Cr₂O₃ films first decreased slightly, and then increased gradually again. Both reached the minimum (35 nm and 13.57 Å) when the bias voltage was − 100 V. However, the bias voltage had little effect on the phase constituents and chemical compositions of AIP Cr₂O₃ films. During the film growth process, the surfaces of Cr₂O₃ films were getting smoother with the negative bias voltage increase, in the meantime, their microstructures evolved from coarse columnar grains to fine columnar grains, short columnar recrystallized grains, and fine columnar grains again.