La doped HfO₂ films have been deposited on Si(100) by atomic layer deposition (ALD) to investigate the film phase transformation after high temperature annealing. The incorporation of La was achieved by depositing HfO₂ and La₂O₃ alternatively, using tetrakis (ethylmethylamino) hafnium, tris[N, N-bis(trimethylsilyl)-amide] lanthanum, and H₂O as precursors. X-ray photoelectron spectroscopy compositional analysis shows that the Hf and La atomic percentage ratio is well controlled by varying the Hf and La precursor dosing cycle ratio. 10nm layered structures were grown from multiple cycles of HfO₂ and a single cycle of La₂O₃ ALD to examine the effects of composition and composition profile on amorphous stabilization. We used X-ray diffraction, spectroscopic ellipsometry and cross section transmission electron microscopy to study the microstructure of the films and found that the introduction of La causes the film crystallization temperature to increase from 500 °C for a pure 10nm HfO₂ film to more than 1000 °C for doped films of the same thickness and a La concentration higher than 20%. 10% La produced stable films at 800 °C. This result indicates that ALD doping La is a potential method to solve the crystallization problem for HfO₂ high-k dielectric gate materials.