Effects of rapid thermal annealing on Hf-doped ZnO films grown by atomic layer deposition

Hafnium doped zinc oxide (HZO) thin films were deposited on thermally grown SiO2 and Si (1 0 0) substrate at 200 °C by atomic layer deposition and were annealed at different temperatures ranging from 400 to 700 °C. The rapid thermal annealing (RTA) effects on structural, luminescent, and electrical properties of HZO films have been investigated by X-ray diffraction, atomic force microscope, spectroscopic ellipsometry, photoluminescence, and Hall-effect measurements. The decrease of the lattice constants with increasing the annealing temperature during the RTA process was observed due to the shift of (1 0 0) diffraction peak towards a higher 2θ angle. The results also show that the intensity of the photoluminescence band increases with the annealing temperature and the photoluminescence band exhibits a red shift. Moreover, the carrier concentration and mobility of the film decrease gradually, which also results in the increase of resistivity.