Preferred orientations and microstructure of MgO films prepared by plasma-enhanced metalorganic chemical vapor deposition

Abstract

NaCl-type magnesium oxide (MgO) films with (110) or (100) preferred orientation were prepared on glass substrate at 400°C by plasma-enhanced metalorganic chemical vapor deposition using Mg(C 5H 7O 2) 2 as a source material. The effect of deposition conditions, such as O 2 flow rate, carrier gas N 2 flow rate and total pressure during the deposition, on the preferred orientation of the MgO films were investigated. The total pressure during the deposition as well as the flow rate ratio of O 2 to Mg source material were found to play a significant role in the preferred orientation of the films. (110)-oriented MgO films were obtained at low pressure under 0.15 Torr, while (100)-oriented MgO films were obtained at high pressure of 1.0 Torr, under the condition of a constant ratio of O 2 to Mg source material. Rutherford backscattering and Auger electron spectra indicated that the O/Mg ratios of the films with (110) and (100) orientation were 0.97 and 1.61, respectively, and no impurities were contained in both the oriented films. Scanning electron micrographs showed that both films with (110) and (100) orientation were composed of closely packed columnar grains of diameter about 60 nm.