Rare earth metal oxide gate thin films prepared by e-beam deposition

Ohmi, Shun–ichiro; Akama, S.; Kikuchi, Akira; Kashiwagi, I.; Ohshima, C.; Taguchi, Junichi; Yamamoto, Hiroyuki; Kobayashi, C.; Sato, Kei; Oshima, K.; Ishiwara, Hiroshi

doi:10.1109/iwgi.2001.967583

Cited by 6 publications

(7 citation statements)

References 11 publications

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“…In other words, the oxide with a larger metal ion radius shows a smaller lattice energy. In the case for rare earth oxides, because lanthanum ions have the largest radius, La 2 O 3 shows the smallest lattice energy within rare earth oxides [12]. …”

Section: Low Permittivity Phenomena Of La2o3 Filmsmentioning

confidence: 99%

Design of Higher-k and More Stable Rare Earth Oxides as Gate Dielectrics for Advanced CMOS Devices

Zhao

2012

Materials

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High permittivity (k) gate dielectric films are widely studied to substitute SiO2 as gate oxides to suppress the unacceptable gate leakage current when the traditional SiO2 gate oxide becomes ultrathin. For high-k gate oxides, several material properties are dominantly important. The first one, undoubtedly, is permittivity. It has been well studied by many groups in terms of how to obtain a higher permittivity for popular high-k oxides, like HfO2 and La2O3. The second one is crystallization behavior. Although it’s still under the debate whether an amorphous film is definitely better than ploy-crystallized oxide film as a gate oxide upon considering the crystal boundaries induced leakage current, the crystallization behavior should be well understood for a high-k gate oxide because it could also, to some degree, determine the permittivity of the high-k oxide. Finally, some high-k gate oxides, especially rare earth oxides (like La2O3), are not stable in air and very hygroscopic, forming hydroxide. This topic has been well investigated in over the years and significant progresses have been achieved. In this paper, I will intensively review the most recent progresses of the experimental and theoretical studies for preparing higher-k and more stable, in terms of hygroscopic tolerance and crystallization behavior, Hf- and La-based ternary high-k gate oxides.

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Section: Low Permittivity Phenomena Of La2o3 Filmsmentioning

confidence: 99%

Design of Higher-k and More Stable Rare Earth Oxides as Gate Dielectrics for Advanced CMOS Devices

Zhao

2012

Materials

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“…In order to achieve a high performance and low power consumption in nano-scale MOSFETs, replacements of poly-Si gate with metal, SiO 2 dielectric with high-κ dielectrics, and Si channel with high mobility channel are required (1) in addition to the atomic-scale control of the high-κ dielectric/Si and metal/high-κ dielectric interfaces. La 2 O 3 , which possesses a high dielectric constant (∼27) (2) and a large band gap (3) has achieved small effective oxide thickness (abbreviated as EOT hereafter) with low leakage current, which are superior to those of HfO 2 or ZrO 2 (4). La 2 O 3 does not form interfacial layer due to the formation of La-silicate at La 2 O 3 /Si-substrate interface (5), which is also a high-κ material (6), hence, high-κ/Si-substrate direct contact structure is achieved.…”

Section: Introductionmentioning

confidence: 99%

Annealing-temperature Dependence of Compositional Depth Profiles and Chemical Bonding States of CeOx/LaOx/Si and LaOx/CeOx/Si Structure

et al. 2009

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We have investigated the influence of post deposition annealing (PDA) on compositional depth profiles and chemical structures of CeOx/LaOx/Si(100) and LaOx/CeOx/Si(100) interfaces by angle-resolved X-ray photoemission spectroscopy. Analyses of Ce 3d and O 1s spectra show that a Ce oxidation state changes from Ce4+ to Ce3+ by PDA in N2 at and above 500{degree sign}C and changes from Ce3+ to Ce4+ by PDA in O2 at 300{degree sign}C. This implies that a Ce oxidation state can be controlled by changing the condition of PDA. The diffusion of Ce and La atom occurs at CeOx/LaOx interface by PDA above 500{degree sign}C.

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“…In order to achieve a smaller equivalent oxide thickness (abbreviated as EOT hereafter) without increasing the leakage current, materials with higher κ are required for the gate insulator. La 2 O 3 , which possesses a high dielectric constant (∼27) and a large band gap (2) has achieved small EOT with low leakage current, which are superior to those of HfO 2 or ZrO 2 (3). Therefore, La-based oxide (4,5) is one of candidate materials for the next generation gate dielectrics.…”

Section: Introductionmentioning

confidence: 99%

Annealing-temperature Dependence of Compositional Depth Profile and Chemical Structures of LaOx/ScOx/Si and ScOx/LaOx/Si Interfacial Transition Layer

et al. 2008

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We have investigated the effects of post deposition annealing on chemical structures of 4 nm LaOx, 4 nm ScOx/Si, 2 nm LaOx/ 2 nm ScOx/Si and 2 nm ScOx/2 nm LaOx/Si interfaces by angleresolved X-ray photoemission spectroscopy. Analyses of Si 2s spectra show that the reactivity between ScOx and Si substrate is lower than that between LaOx and Si substrate. Analyses of O 1s spectra show that the absorption of moisture in the LaOx is suppressed by 2 nm ScOx/2 nm LaOx/Si structure. In addition, the electronic band structure of ScOx/Si(100) was determined.

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Rare earth metal oxide gate thin films prepared by e-beam deposition

Cited by 6 publications

References 11 publications

Design of Higher-k and More Stable Rare Earth Oxides as Gate Dielectrics for Advanced CMOS Devices

Design of Higher-k and More Stable Rare Earth Oxides as Gate Dielectrics for Advanced CMOS Devices

Annealing-temperature Dependence of Compositional Depth Profiles and Chemical Bonding States of CeOx/LaOx/Si and LaOx/CeOx/Si Structure

Annealing-temperature Dependence of Compositional Depth Profile and Chemical Structures of LaOx/ScOx/Si and ScOx/LaOx/Si Interfacial Transition Layer

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