Interfacial reactions as a function of the stack structure of Al 2O3 and HfO2 grown on Si by atomic-layer deposition were examined by various physical and electrical measurements. In the case of an Al2O3 film with a buffer layer of HfO 2, reactions between the Al2O3 and Si layers were suppressed, while a HfO2 film with an Al2O 3 buffer layer on the Si readily interacted with Si, forming a Hf-Al-Si-O compound. The thickness of the interfacial layer increased dramatically after an annealing treatment in which a buffer layer of Al 2O3 was used, while no change in thickness was observed in the film in which a HfO2 buffer layer was used. Moreover, the stoichiometric change caused by a different reaction process altered the chemical state of the films, which affected charge trapping and the interfacial trap density.
Bibliographical noteFunding Information:
This work was supported by the National Program for Tera-level Nanodevices of the Ministry of Science and Technology as one of the 21 Century Frontier Programs.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)