An investigation of the electrical characteristics of ultrathin ZrO2 formed by anodization in an ammonium tartrate electrolyte is reported. Compared with low temperature thermal oxidation, the formation of zirconium oxide by anodization shows self-limiting oxidation behavior with an increase in time, and, thus, provides superior control of the oxide thickness. The growth of anodized oxide inhibits aggressive oxidation by blocking the flow of current through a dielectric since the location at which the oxide forms would become a region of high resistance. The equivalent oxide thickness of ultrathin zirconium oxide by anodization within an acceptable dispersion was scaled down to 11.4 Å with leakage current density of less than 1.5×10-3 A/cm2 at Vfb of -1 V. The density of the interface state and fixed charge density of zirconium oxide using the anodization process are also discussed. © 2003 American Vacuum Society.