Effective work function modulation of TaN metal gate on HfO2 after postmetallization annealing
2007; American Institute of Physics; Volume: 91; Issue: 11 Linguagem: Inglês
10.1063/1.2783472
ISSN1520-8842
AutoresYouhei Sugimoto, Masanari Kajiwara, Keisuke Yamamoto, Yuusaku Suehiro, Dong Wang, Hiroshi Nakashima,
Tópico(s)Advancements in Semiconductor Devices and Circuit Design
ResumoThe effective work function (Φm,eff) of TaN on HfO2 after postmetallization annealing (PMA) was investigated using TaN∕HfO2∕SiO2∕Si as a sample structure. We found that Φm,eff on HfO2 is stable at PMA temperatures of less than 600°C and is 4.6eV, which is approximately 0.2eV higher than that on SiO2. In contrast, Φm,eff is modulated by PMA at temperatures greater than 750°C. An analysis by x-ray photoelectron spectroscopy suggests that the increased Φm,eff is strongly related to Ta oxide formation near the TaN∕HfO2 interface. The modulation of Φm,eff on HfO2 is discussed on the basis of intrinsic and extrinsic Fermi level pinning due to Ta–O bond formation at the TaN∕HfO2 interface.
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