Influence of duty cycle on the structure and secondary electron emission properties of MgO films deposited by pulsed mid-frequency magnetron sputtering

MgO films were deposited by using a pulsed mid-frequency magnetron sputtering technique. X-ray diffraction, atomic force microscopy, Rutherford backscattering, and a diode discharge device were used to characterize crystalline structure, surface morphology, oxygen content, and secondary electron emission (gamma) coefficient of the films, respectively. The influence of the duty cycle on the structure and secondary electron emission properties of the films was systematically studied. No remarkable change in the oxygen content in the films with duty cycle can be observed, but crystalline structure, surface morphology, and secondary electron emission properties of the films are significantly affected by the duty cycle. All films exhibit a strong (220) preferred orientation growth, but the increase of the duty cycle results in a continuous decrease in grain size, surface roughness, and gamma coefficient, as well as an increase in the defect density. The increase of the defect density with increasing duty cycle is the main reason for the reduction of the gamma coefficient. (C) 2003 American Institute of Physics.