Dependences of effective work functions of TaN on HfO2 and SiO2 on post-metallization anneal

Youhei Sugimoto; Masanari Kajiwara; Keisuke Yamamoto; Yuusaku Suehiro; Dong Wang; Hiroshi Nakashima

doi:10.1016/j.tsf.2008.08.058

Dependences of effective work functions of TaN on HfO₂ and SiO₂ on post-metallization anneal

Youhei Sugimoto, Masanari Kajiwara, Keisuke Yamamoto, Yuusaku Suehiro, Dong Wang, Hiroshi Nakashima

Research output: Contribution to journal › Article › peer-review

13 Citations (Scopus)

Abstract

We fabricated TaN-gate electrodes on HfO₂ and SiO₂ films by wet etching using NH₄OH/H₂O₂ solution and investigated the electrical and structural properties of the TaN/SiO₂ and TaN/HfO₂ interfacial layers. The effective work function (Φ_m,eff) of TaN on SiO₂ and HfO₂ are 4.4 and 4.6 eV, respectively. The Φ_m,eff on SiO₂ remained constant after post-metallization anneal (PMA) at temperatures of up to 750 °C and increased after 900 °C, but the Φ_m,eff on HfO₂ increased after PMA at 750 °C. The analysis by X-ray photoelectron spectroscopy (XPS) indicated that Ta oxide was formed near the TaN/SiO₂ and TaN/HfO₂ interfacial layers after the annealing at 900 °C. It was concluded that the Φ_m,eff instability is strongly associated with the Ta-O bond formation at the interfaces.

Original language	English
Pages (from-to)	204-206
Number of pages	3
Journal	Thin Solid Films
Volume	517
Issue number	1
DOIs	https://doi.org/10.1016/j.tsf.2008.08.058
Publication status	Published - Nov 3 2008

All Science Journal Classification (ASJC) codes

Electronic, Optical and Magnetic Materials
Surfaces and Interfaces
Surfaces, Coatings and Films
Metals and Alloys
Materials Chemistry

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@article{8353f4a23bb848b49552cd72cdfb5fa1,

title = "Dependences of effective work functions of TaN on HfO2 and SiO2 on post-metallization anneal",

abstract = "We fabricated TaN-gate electrodes on HfO2 and SiO2 films by wet etching using NH4OH/H2O2 solution and investigated the electrical and structural properties of the TaN/SiO2 and TaN/HfO2 interfacial layers. The effective work function (Φm,eff) of TaN on SiO2 and HfO2 are 4.4 and 4.6 eV, respectively. The Φm,eff on SiO2 remained constant after post-metallization anneal (PMA) at temperatures of up to 750 °C and increased after 900 °C, but the Φm,eff on HfO2 increased after PMA at 750 °C. The analysis by X-ray photoelectron spectroscopy (XPS) indicated that Ta oxide was formed near the TaN/SiO2 and TaN/HfO2 interfacial layers after the annealing at 900 °C. It was concluded that the Φm,eff instability is strongly associated with the Ta-O bond formation at the interfaces.",

author = "Youhei Sugimoto and Masanari Kajiwara and Keisuke Yamamoto and Yuusaku Suehiro and Dong Wang and Hiroshi Nakashima",

note = "Funding Information: This study was supported by a Grant-in-Aid for Science Research B (18360152) from the Ministry of Education, Culture, Sports, Science and Technology of Japan. XPS measurements were carried out using the facilities of the Center of Advanced Instrumental Analysis of Kyushu University.",

year = "2008",

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doi = "10.1016/j.tsf.2008.08.058",

language = "English",

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T1 - Dependences of effective work functions of TaN on HfO2 and SiO2 on post-metallization anneal

AU - Sugimoto, Youhei

AU - Kajiwara, Masanari

AU - Yamamoto, Keisuke

AU - Suehiro, Yuusaku

AU - Wang, Dong

AU - Nakashima, Hiroshi

N1 - Funding Information: This study was supported by a Grant-in-Aid for Science Research B (18360152) from the Ministry of Education, Culture, Sports, Science and Technology of Japan. XPS measurements were carried out using the facilities of the Center of Advanced Instrumental Analysis of Kyushu University.

PY - 2008/11/3

Y1 - 2008/11/3

N2 - We fabricated TaN-gate electrodes on HfO2 and SiO2 films by wet etching using NH4OH/H2O2 solution and investigated the electrical and structural properties of the TaN/SiO2 and TaN/HfO2 interfacial layers. The effective work function (Φm,eff) of TaN on SiO2 and HfO2 are 4.4 and 4.6 eV, respectively. The Φm,eff on SiO2 remained constant after post-metallization anneal (PMA) at temperatures of up to 750 °C and increased after 900 °C, but the Φm,eff on HfO2 increased after PMA at 750 °C. The analysis by X-ray photoelectron spectroscopy (XPS) indicated that Ta oxide was formed near the TaN/SiO2 and TaN/HfO2 interfacial layers after the annealing at 900 °C. It was concluded that the Φm,eff instability is strongly associated with the Ta-O bond formation at the interfaces.

AB - We fabricated TaN-gate electrodes on HfO2 and SiO2 films by wet etching using NH4OH/H2O2 solution and investigated the electrical and structural properties of the TaN/SiO2 and TaN/HfO2 interfacial layers. The effective work function (Φm,eff) of TaN on SiO2 and HfO2 are 4.4 and 4.6 eV, respectively. The Φm,eff on SiO2 remained constant after post-metallization anneal (PMA) at temperatures of up to 750 °C and increased after 900 °C, but the Φm,eff on HfO2 increased after PMA at 750 °C. The analysis by X-ray photoelectron spectroscopy (XPS) indicated that Ta oxide was formed near the TaN/SiO2 and TaN/HfO2 interfacial layers after the annealing at 900 °C. It was concluded that the Φm,eff instability is strongly associated with the Ta-O bond formation at the interfaces.

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Dependences of effective work functions of TaN on HfO₂ and SiO₂ on post-metallization anneal

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