Direct observation of bias-dependence potential distribution in metal/HfO{sub 2} gate stack structures by hard x-ray photoelectron spectroscopy under device operation
- National Institute for Materials Science, Advanced Electric Materials Center, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)
- National Institute for Materials Science, NIMS Beamline Station at SPring-8, 1-1-1 Kôto, Sayo-cho, Sayo-gun, Hyogo 679-5148 (Japan)
Although gate stack structures with high-k materials have been extensively investigated, there are some issues to be solved for the formation of high quality gate stack structures. In the present study, we employed hard x-ray photoelectron spectroscopy in operating devices. This method allows us to investigate bias dependent electronic states, while keeping device structures intact. Using this method, we have investigated electronic states and potential distribution in gate metal/HfO{sub 2} gate stack structures under device operation. Analysis of the core levels shifts as a function of the bias voltage indicated that a potential drop occurred at the Pt/HfO{sub 2} interface for a Pt/HfO{sub 2} gate structure, while a potential gradient was not observed at the Ru/HfO{sub 2} interface for a Ru/HfO{sub 2} gate structure. Angle resolved photoelectron spectroscopy revealed that a thicker SiO{sub 2} layer was formed at the Pt/HfO{sub 2} interface, indicating that the origin of potential drop at Pt/HfO{sub 2} interface is formation of the thick SiO{sub 2} layer at the interface. The formation of the thick SiO{sub 2} layer at the metal/high-k interface might concern the Fermi level pinning, which is observed in metal/high-k gate stack structures.
- OSTI ID:
- 22275599
- Journal Information:
- Journal of Applied Physics, Vol. 115, Issue 4; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
Similar Records
Improved thermal stability and electrical properties of atomic layer deposited HfO{sub 2}/AlN high-k gate dielectric stacks on GaAs
Chemical analysis of HfO{sub 2}/Si (100) film systems exposed to NH{sub 3} thermal processing