Thermal plasma CVD of PSZ and double layered TiN/PSZ coatings by injection of alkoxides solutions with H2O

Coatings of partially Y2O3-stabilized ZrO2 (PSZ) (Y > 2 at.%) and double layered TiN/PSZ films were deposited on Si wafers at 700 °C from zirconium tetra-buthoxide (ZTBO), yttrium tri-buthoxide (YTBO) and/or titanium tetra-ethoxide by chemical vapor deposition with H2O in a thermal Ar/N2/H2 plasma. A small amount of H2O was fed into the plasma to oxidize the ZTBO and YTBO to produce the PSZ coatings. Double layered TiN/PSZ film coatings were deposited without severe oxidation of under-layered TiN by controlling the feeding rate of H2O. The product phases were identified by grazing incidence X-ray-diffractometry. The surfaces and cross-sections of the PSZ and double layered TiN/PSZ coatings were observed by scanning electron microscopy. An in-depth semi-quantitative analysis of the double layered TiN/PSZ films was performed by X-ray photoelectron spectroscopy, revealing the changes in the concentrations of Zr, Y, Ti, O, and N with depth. The effect of the Y content in mixed solutions of ZTBO and YTBO on the evolution of ZrO2 is examined. It is proposed that the controlled feed rate of H2O is effective in producing coatings of PSZ on TiN films without severe oxidation.