Thickness dependence on crystalline structure and interfacial reactions in HfO_2 films on InP (001) grown by atomic layer deposition

摘要

The crystalline structure and interfacial reactions in HfO_2 films grown on InP (001) substrates was investigated as a function of film thickness. High resolution transmission electron microscopy and x-ray diffraction measurements were used to investigate changes in the crystalline structure of the HfO_2 films. As the thickness of the HfO_2 increased, the crystal structure was transformed from monoclinic to tetragonal, and the interfacial layer between the HfO_2 film and the InP substrate disappeared. High resolution x-ray photoelectron spectroscopy was also applied to confirm the existence of an interfacial chemical reaction in HfO_2/InP. An interfacial self-cleaning effect occurred during the atomic layer deposition process, resulting in a clear interface with no indication of an interfacial layer between the HfO_2 film and the InP surface. Finally, the crystallization process in the HfO_2 films was found to be significantly affected by the interfacial energy.