Electrical properties of sol–gel derived Mg-doped Al₂O₃ films

Abstract

Highly homogeneous and dense Mg-doped Al₂O₃ films were prepared using sol–gel method. Similar trends occur in the current–voltage characteristics of Al_1−xMg_xO_3−δ series (x = 0, 0.5, 2 and 10 %) films, while 7.7 and 33.3 % Mg-doped Al₂O₃ films exhibit different trends, and the 33.3 % Mg-doped Al₂O₃ films have the lowest leakage current, which almost linearly increases with the applied voltage. The dielectric strength of the Al_1−xMg_xO_3−δ series (x = 0.5, 2 and 10 %) films are slightly lower than that of undoped Al₂O₃ films, while the 7.7 and 33.3 % Mg-doped Al₂O₃ films possess higher dielectric strength than the undoped Al₂O₃ films. The Ohmic conduction dominates the leakage current of Al_1−xMg_xO_3−δ (x = 0, 7.7 and 33.3 %) films under lower electric field, while the space-charge-limited-current and Schottky emission, and even other conduction mechanisms, could co-exist under higher electric field.