MOCVD of ZrO2 and HfO2 thin films from modified monomeric precursors

Metal-organic precursors of Zr and Hf with excellent vaporization characteristics and low decomposition temperatures are reported. The new mixed alkoxide precursors [Zr(O'Bu)(2)(tbaoac)(2)] (1) and [Hf(O'Bu)(2)(tbaoac)(2)] (2) were synthesized by facile alcohol-exchange reactions between [M(O'Pr)(2)(L)(2)] and tert-butanol [M = Zr, Hf; L= tert-butylacetoacetate (tbaoac)]. The six-coordinated monomeric compounds are volatile, stable in solution, and less sensitive to air and moisture compared to parent alkoxides such as [Zr(O'Bu)(4)] and [Hf(O'Bu)(4)]. It was possible to grow ZrO2 and HfO2 at low deposition temperatures, and the films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and Rutherford back scattering (RBS) analysis. [Zr(O'Bu)(2)(tbaoac)(2)], evaluated in a rnultiwafer planetary MOCVD reactor combined with a liquid delivery system, yielded ZrO2 films that show promise for gate oxide applications.