Bias-assisted epitaxial Ir/YSZ (1 0 0) substrate for diamond nucleation and growth

Abstract

Iridium (Ir) films were deposited on yttrium stabilized zirconia (YSZ) substrates by bias-assisted RF magnetron sputtering. The orientation of Ir films can be orientally modulated by negative substrate bias, and then used for diamond nucleation and growth by microwave plasma chemical vapor deposition technology combined with the bias-enhanced nucleation process. The morphology, microstructure and composition of Ir and diamond films were investigated by scanning electron microscope (SEM), atomic force microscope, X-ray diffraction (XRD), Raman and X-ray photoelectron spectroscopy. The morphological characterizations of Ir films showed that the grain shape was more uniform and regular symmetry with the increase of substrate negative bias voltage. XRD showed that the crystal orientation of the Ir films changed from (111) texture to (200) texture, and the optimal (200) preferred orientation is achieved under a substrate bias of −150 V. SEM images of diamond films exhibited that the diamond islands gradually merge into continuous diamond films and present a high degree of epitaxy. The crystalline quality of the central region of the epitaxial diamond films is higher than that of the edge region due to the substrate temperature gradient. The Raman full width at half maximum of the central region was 5.75 cm−1.