Film microstructure-deposition condition relationships in the growth of epitaxial NiO films by metalorganic chemical vapor deposition on oxide and metal substrates

High-quality epitaxial or highly textured NiO thin films can be grown at te mperatures of 400-750 degrees C by low-pressure metalorganic chemical vapor deposition (MOCVD) on MgO, SrTiO3, C-cut sapphire, as well as on single cr ystal and highly textured Ni (200) metal substrates using Ni(dpm)(2) (dpm = dipivaloylmethanate) as the volatile precursor and O-2 or H2O as the oxidi zer/protonolyzer. X-ray diffraction (XRD), scanning electron microscopy/ene rgy dispersive detection (SEM/EDX), and atomic force microscopy (AFM) confi rm that the O-2-derived NiO films are smooth and that the quality of the ep itaxy can be improved by decreasing the growth temperature and/or the precu rsor flow rate. However, low growth temperatures (400-500 degrees C) lead t o rougher surfaces and carbon contamination. The H2O-derived NiO films, whi ch can be obtained only at relatively high temperatures (650-750 degrees C) , exhibit slightly broader omega scan full width half-maximum (FWHM) values and rougher surfaces but no carbon contamination. Using H2O as the oxidize r/protonolyzer, smooth and highly textured NiO (111) films can be grown on easily oxidized single crystal and highly textured Ni (200) metal substrate s, which is impossible when O-2 is the oxidizer. The textural quality of th ese films depends on both the quality of the metal substrates and the gaseo us precursor flow rate.