Abstract
We have investigated theoretically the cause of the substantial threshold voltage (Vth) shifts observed in Hf-related high-k gate stacks with p+poly-Si gates, by focusing on the ionic nature of HfO2. The oxygen vacancy (Vo) level in ionic HfO2 is located in a relatively higher part of the band gap. This high position of the Vo level results in a significant elevation of the Fermi level for p+poly-Si gates, if the p+poly-Si gate is in contact with the high-k HfO2. Vo formation in the HfO2 induces a subsequent electron transfer across the interface, causing a substantial Vth shifts in p+poly-Si gate MISFETs. Moreover, our theory also systematically reproduces other recent experimental results.
Original language | English |
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Pages (from-to) | 305-310 |
Number of pages | 6 |
Journal | Thin Solid Films |
Volume | 508 |
Issue number | 1-2 |
DOIs | |
Publication status | Published - 2006 Jun 5 |
Externally published | Yes |
Keywords
- Fermi level pinning
- High-k HfO dielectrics
- Oxygen vacancy
- Poly-Si gates
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Metals and Alloys
- Materials Chemistry