Characterization of inductively coupled RF plasmas for plasma-assisted mist CVD of ZnO films

Abstract

A plasma-assisted mist chemical vapor deposition (CVD) system with a high-density inductivity coupled RF plasma (ICP) source has been developed for low-temperature and high-rate deposition of zinc oxide films. In this paper, characterization of an ICP for plasma-assisted mist CVD is reported. It was found that the plasma density measured with a cylindrical Langmuir probe was as high as 1.2 × 1011 cm−3 and the electron temperature was 1.0 − 2.5 eV for an Ar plasma. The gas temperature in the ICP determined from molecular optical emission spectroscopy was 1450 K at an RF power of 1000 W for an Ar/air plasma. These results demonstrate that a plasma sustained by an inductively coupled RF plasma source has sufficient enthalpy for vaporization of mists and also has a high density for efficient dissociation of precursors and generation of oxygen radials during ZnO film deposition using plasma-assisted mist CVD.