Chlorine mobility during annealing in N-2 in ZrO2 and HfO2 films grown by atomic layer deposition

Atomic layer deposition (ALD) growth of high-kappa dielectric films (ZrO2 and HfO2) was performed using ZrCl4, HfCl4, and H2O as precursors. In this work, we use time of flight secondary ion mass spectrometry to investigate the chlorine distribution in ALD grown ZrO2 and HfO2 films, and its evolution during rapid thermal processes in nitrogen atmosphere. Chlorine outdiffusion is found to depend strongly upon annealing temperature and weakly upon the annealing time. While in ZrO2 chlorine concentration is significantly decreased already at 900 degreesC, in HfO2 it is extremely stable, even at temperatures as high as 1050 degreesC.