Capacitance- and current-voltage characteristics of ZrO₂/Al₂O₃/ZrO₂ (ZAZ) capacitors with an addition of hydrogen peroxide (H₂O₂) were identified. From the results, leakage current and interface trap density of the H₂O₂-doped devices decreased due to reduction of oxygen vacancies in ZAZ layers. H₂O₂ effect on the electrical behaviors was qualitatively analyzed.