Post-cleaning effect on a HfO2 gate stack using a NF3/NH3 plasma

Min Seon Lee, Hoon Jung Oh, Joo Hee Lee, In Geun Lee, Woo Gon Shin, Kyu Dong Kim, Jin Gu Park, Dae Hong Ko

Research output: Contribution to journalArticlepeer-review


The effects of dry cleaning of a HfO2 gate stack using NF3 only and a NF3/NH3 gas mixture plasma were investigated. The plasma dry cleaning process was carried out after HfO2 deposition using an indirect down-flow capacitively coupled plasma (CCP) system. An analysis of the chemical composition of the HfO2 gate stacks by XPS indicated that fluorine was incorporated into the HfO2 films during the plasma dry cleaning. Significant changes in the HfO2 chemical composition were observed as a result of the NF3 dry cleaning, while they were not observed in this case of NF3/NH3 dry cleaning. TEM results showed that the interfacial layer (IL) between the HfO2 and Si thickness was increased by the plasma dry cleaning. However, in the case of NF3/NH3 dry cleaning using 150 W, the IL thickness was suppressed significantly compared to the sample that had not been dry cleaned. Its electrical properties were also improved, including the low gate leakage currents, and reduced EOT. Finally, the finding show that the IL thickness of the HfO2 gate stack can be controlled by using the novel NF3/NH3 dry cleaning process technique without any the significant changes in chemical composition and metal-oxide-semiconductor (MOS) capacitor characteristics.

Original languageEnglish
Pages (from-to)4808-4813
Number of pages6
JournalJournal of Nanoscience and Nanotechnology
Issue number5
Publication statusPublished - 2016 May

Bibliographical note

Publisher Copyright:
Copyright © 2016 American Scientific Publishers.

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • General Chemistry
  • Biomedical Engineering
  • General Materials Science
  • Condensed Matter Physics


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