An investigation of annealing on the dielectric performance of TiO2 thin films

The impact of annealing on the dielectric performance of TiO2 thin films synthesized by PECVD was investigated. Films annealed between 500 and 700 degrees C have an anatase crystal structure, while 800 degrees C annealed films display the rutile phase. The optimal annealing temperature was 600 degrees C, which both maximized the dielectric constant and minimized the leakage current density. The intrinsic dielectric constant of TiO2 improved from 82 +/- 10 in as-deposited films to 168 +/- 30 after annealing. The leakage current of optimized films was superior to the SiO2 control samples over a range of equivalent oxide thickness. Fowler - Nordheim tunnelling and Frenkel - Poole conduction were observed in the optimized films, while Schottky emission dominated leakage current at other conditions.