Suppression of Crystallization of Tantalum Oxide Thin Film by Doping with Zirconium

Metal oxide high dielectric constant materials suffer from crystallization after a high-temperature annealing step, which hinders their applications in future metal oxide semiconductor devices. We observed that when the tantalum oxide thin film was doped with zirconium, its amorphous-to-polycrystalline transition temperature was raised by more than 200°C. The crystal structure and grain size were affected by the dopant concentration, annealing temperature, and film thickness. The doping method changed the crystallization mechanism of the film. Therefore, the doping method is effective in improving the high-k dielectric electrical properties.