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 Al1−xMgxO3−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 Al1−xMgxO3−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 Al1−xMgxO3−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.