In this paper we describe the growth of zinc oxide (ZnO) films on a-plane sapphire substrates by plasma enhanced metal organic chemical vapor deposition (PE-MOCVD) employing microwave excited high-density plasma. In detail, we discuss the effects of ion-bombardmentassist and high temperature on structural properties, electrical properties, optical properties, impurity concentration and thermostability by X-ray diffraction (XRD), field emission scanning electron microscopy, Hall effect measurement at room temperature, photoluminescence, secondary ion mass spectrometry and thermal desorption spectroscopy. Ion-bombardment energy is controlled by the condition of radiofrequency (RF) self bias. Moderate ion-bombardment enhances crystallinity, mobility and thermostability, and reduces concentrations of carbon and hydrogen in the films. By raising the growth temperature up to 550 °C, the qualities of films are improved. High quality ZnO film was successfully grown at 550 °C, which is a relatively low temperature compared to general MOCVD. Its full width at half maximum (FWHM) of XRD (0002) rocking curve, carrier concentration and mobility are 0.12°, 5 × 1016/cm3, and 89cm 2/(V·s), respectively.
ASJC Scopus subject areas
- Physics and Astronomy(all)