Theoretical studies on the physical properties of poly-Si and metal gates/HfO2 related high-K dielectrics interfaces

Kenji Shiraishi; Kazuyoshi Torii; Yasushi Akasaka; Takashi Nakayama; Takashi Nakaoka; Seiichi Miyazaki; Toyohiro Chikyow; Keisaku Yamada; Yasuo Nara

doi:10.1149/1.2209298

Theoretical studies on the physical properties of poly-Si and metal gates/HfO₂ related high-K dielectrics interfaces

Kenji Shiraishi, Kazuyoshi Torii, Yasushi Akasaka, Takashi Nakayama, Takashi Nakaoka, Seiichi Miyazaki, Toyohiro Chikyow, Keisaku Yamada, Yasuo Nara

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

3 Citations (Scopus)

Abstract

We have theoretically investigated poly-Si and metal gates on Hf-related high-k gate dielectrics. First, we have investigated the cause of the substantial threshold voltage (V_th) shifts observed in Hf-related high-k gate stacks with p+poly-Si gates. The oxygen vacancy (Vo) level in ionic HfO₂ is located in a relatively higher part of the band gap. If the p+poly-Si-gate is in contact with HfO₂, Vo formation in the HfO ₂ induces a subsequent electron transfer across the interface because of the higher energy level position of Vo, causing a substantial V _th, shifts in p+poly-Si gate MISFETs. Next, we also investigate the microscopic electronic structures at metal gates/HfO₂ interfaces. We have found that the wave functions of metal induced gap states (MIGS) have large amplitudes both around Hf and O atoms, which may be the cause of unusual work function behaviors of p-like metals. copyright The Electrochemical Society.

Original language	English
Title of host publication	Physics and Technology of High-k Gate Dielectrics III
Publisher	Electrochemical Society Inc.
Pages	479-493
Number of pages	15
Edition	5
ISBN (Electronic)	1566774446
DOIs	https://doi.org/10.1149/1.2209298
Publication status	Published - 2006
Externally published	Yes
Event	3rd International Symposium on High Dielectric Constant Gate Stacks - 208th Meeting of the Electrochemical Society - Los Angeles, CA, United States Duration: 2005 Oct 16 → 2005 Oct 21

Publication series

Name	ECS Transactions
Number	5
Volume	1
ISSN (Print)	1938-5862
ISSN (Electronic)	1938-6737

Other

Other	3rd International Symposium on High Dielectric Constant Gate Stacks - 208th Meeting of the Electrochemical Society
Country/Territory	United States
City	Los Angeles, CA
Period	05/10/16 → 05/10/21

ASJC Scopus subject areas

Engineering(all)

Access to Document

10.1149/1.2209298

Cite this

Shiraishi, K., Torii, K., Akasaka, Y., Nakayama, T., Nakaoka, T., Miyazaki, S., Chikyow, T., Yamada, K., & Nara, Y. (2006). Theoretical studies on the physical properties of poly-Si and metal gates/HfO₂ related high-K dielectrics interfaces. In Physics and Technology of High-k Gate Dielectrics III (5 ed., pp. 479-493). (ECS Transactions; Vol. 1, No. 5). Electrochemical Society Inc.. https://doi.org/10.1149/1.2209298

Theoretical studies on the physical properties of poly-Si and metal gates/HfO₂ related high-K dielectrics interfaces. / Shiraishi, Kenji; Torii, Kazuyoshi; Akasaka, Yasushi et al.

Physics and Technology of High-k Gate Dielectrics III. 5. ed. Electrochemical Society Inc., 2006. p. 479-493 (ECS Transactions; Vol. 1, No. 5).

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

Shiraishi, K, Torii, K, Akasaka, Y, Nakayama, T, Nakaoka, T, Miyazaki, S, Chikyow, T, Yamada, K & Nara, Y 2006, Theoretical studies on the physical properties of poly-Si and metal gates/HfO₂ related high-K dielectrics interfaces. in Physics and Technology of High-k Gate Dielectrics III. 5 edn, ECS Transactions, no. 5, vol. 1, Electrochemical Society Inc., pp. 479-493, 3rd International Symposium on High Dielectric Constant Gate Stacks - 208th Meeting of the Electrochemical Society, Los Angeles, CA, United States, 05/10/16. https://doi.org/10.1149/1.2209298

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abstract = "We have theoretically investigated poly-Si and metal gates on Hf-related high-k gate dielectrics. First, we have investigated the cause of the substantial threshold voltage (Vth) shifts observed in Hf-related high-k gate stacks with p+poly-Si gates. The oxygen vacancy (Vo) level in ionic HfO2 is located in a relatively higher part of the band gap. If the p+poly-Si-gate is in contact with HfO2, Vo formation in the HfO 2 induces a subsequent electron transfer across the interface because of the higher energy level position of Vo, causing a substantial V th, shifts in p+poly-Si gate MISFETs. Next, we also investigate the microscopic electronic structures at metal gates/HfO2 interfaces. We have found that the wave functions of metal induced gap states (MIGS) have large amplitudes both around Hf and O atoms, which may be the cause of unusual work function behaviors of p-like metals. copyright The Electrochemical Society.",

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