Spectroscopic study of plasma using zirconium tetra-tert-butoxide for the plasma enhanced chemical vapor deposition of zirconium oxide

Plasma enhanced chemical vapor deposition of zirconium oxide using zirconium tetra-tert-butoxide (ZTB) as a metalorganic precursor, Ar as a carrier of the ZTB vapor, and O2 as an oxidant was investigated by using optical emission spectroscopy (OES), Langmuir probe, and x-ray photoelectron spectroscopy (XPS). The electron temperature (Te) and the O2 to Ar flow rate ratio (O2/Ar) were found to dominate the plasma chemistry: the Te determined the maximum Zr and Zr+ emission intensities at an intermediate pressure of 45 mTorr, the high C/C2 emission intensity ratio in the oxygen-rich plasma, and the transition between the dissociation-dominated chemistry at low pressures and the recombination-dominated chemistry at high pressures. The O2/Ar ratio changed the relative abundance of various atomic and diatomic species in the plasma: both ionic and atomic Zr species were depleted with the addition of O2 and a significant amount of ZrO and CO was produced. The O2/Ar ratio and Te determined the concentration ratio ...