Current transport analysis of ZrO2 thin films: Effects of post-deposition annealing

We report on the effects of post-deposition annealing on the electrical properties and the dielectric performance of atomic layer-deposited ZrO2 thin films investigated by using capacitance-voltage and current-voltage measurements. ZrO2 films crystallized by post-deposition annealing in vacuum showed an enhanced dielectric constant and energy band gap, but the leakage current was increased. The Poole-Frankel and the trap assisted tunneling mechanisms were considered to be the major leakage current conduction processes and the charge trap energy level was reduced from 1.09–1.13 eV to 0.81–0.84 eV by post-deposition annealing. The increase in the leakage current in the crystallized films can be explained by considering structural defect relaxation or grain boundary formation.