Undoped and Bi-doped zirconia films have been grown by MOCVD on both Si(100) single crystals, and fused SiO2 substrates. Zr(C5H7O2)(4) and Bi(C6H5)(3) precursors have been used as metal sources. A tetragonal zirconia phase forms on both substrates. Firing of undoped ZrO2 thin films causes a tetragonal to monoclinic transformation above 500 degrees C. By contrast, Bi-doped films remain tetragonal up to 800 degrees C. XPS data provide evidence that progressive heat treatment of Bi-doped ZrO2 causes surface Bi-segregation. Films on SiO2 and Si(100) are preferentially oriented with (110) planes parallel to the surface, and the texture increases with the Bi doping level. Film morphology has been investigated by scanning electron microscopy.