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Title: Role of oxygen vacancy in HfO{sub 2}/SiO{sub 2}/Si(100) interfaces

Abstract

We have investigated the interface states in HfO{sub 2}/SiO{sub 2}/Si(100) systems that were prepared by using the in situ pulsed laser deposition technique. X-ray photoelectron spectroscopy data revealed that when the HfO{sub 2} film thickness exceeds 11 A, the film composition undergoes a systematic change from Hf silicate to oxygen-deficient HfO{sub x<2}. Furthermore, we determined that the evolution of the interface states clearly depends on the oxygen condition applied during the film growth and that the oxygen vacancy is an important parameter for Hf silicate formation.

Authors:
; ; ; ; ;  [1];  [2];  [2]
  1. CSCMR and School of Physics, Seoul National University, Seoul 151-747 (Korea, Republic of)
  2. (Korea, Republic of)
Publication Date:
OSTI Identifier:
20779302
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 88; Journal Issue: 19; Other Information: DOI: 10.1063/1.2201050; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CRYSTAL GROWTH; CRYSTALS; DIELECTRIC MATERIALS; ENERGY BEAM DEPOSITION; HAFNIUM OXIDES; HAFNIUM SILICATES; INTERFACES; LASER RADIATION; OXYGEN; PULSED IRRADIATION; SEMICONDUCTOR MATERIALS; SILICON; SILICON OXIDES; THICKNESS; THIN FILMS; VACANCIES; X-RAY PHOTOELECTRON SPECTROSCOPY

Citation Formats

Cho, Deok-Yong, Oh, S.-J., Chang, Y.J., Noh, T.W., Jung, Ranju, Lee, Jae-Cheol, ReCOE and School of Physics, Seoul National University, Seoul 151-747, and Samsung Advanced Institute of Technology, Suwon 440-900. Role of oxygen vacancy in HfO{sub 2}/SiO{sub 2}/Si(100) interfaces. United States: N. p., 2006. Web. doi:10.1063/1.2201050.
Cho, Deok-Yong, Oh, S.-J., Chang, Y.J., Noh, T.W., Jung, Ranju, Lee, Jae-Cheol, ReCOE and School of Physics, Seoul National University, Seoul 151-747, & Samsung Advanced Institute of Technology, Suwon 440-900. Role of oxygen vacancy in HfO{sub 2}/SiO{sub 2}/Si(100) interfaces. United States. doi:10.1063/1.2201050.
Cho, Deok-Yong, Oh, S.-J., Chang, Y.J., Noh, T.W., Jung, Ranju, Lee, Jae-Cheol, ReCOE and School of Physics, Seoul National University, Seoul 151-747, and Samsung Advanced Institute of Technology, Suwon 440-900. Mon . "Role of oxygen vacancy in HfO{sub 2}/SiO{sub 2}/Si(100) interfaces". United States. doi:10.1063/1.2201050.
@article{osti_20779302,
title = {Role of oxygen vacancy in HfO{sub 2}/SiO{sub 2}/Si(100) interfaces},
author = {Cho, Deok-Yong and Oh, S.-J. and Chang, Y.J. and Noh, T.W. and Jung, Ranju and Lee, Jae-Cheol and ReCOE and School of Physics, Seoul National University, Seoul 151-747 and Samsung Advanced Institute of Technology, Suwon 440-900},
abstractNote = {We have investigated the interface states in HfO{sub 2}/SiO{sub 2}/Si(100) systems that were prepared by using the in situ pulsed laser deposition technique. X-ray photoelectron spectroscopy data revealed that when the HfO{sub 2} film thickness exceeds 11 A, the film composition undergoes a systematic change from Hf silicate to oxygen-deficient HfO{sub x<2}. Furthermore, we determined that the evolution of the interface states clearly depends on the oxygen condition applied during the film growth and that the oxygen vacancy is an important parameter for Hf silicate formation.},
doi = {10.1063/1.2201050},
journal = {Applied Physics Letters},
number = 19,
volume = 88,
place = {United States},
year = {Mon May 08 00:00:00 EDT 2006},
month = {Mon May 08 00:00:00 EDT 2006}
}
  • Dynamics of Si(100)-oxidation processes at the Si/SiO{sub 2} interface and in the SiO{sub 2} region are investigated focusing on SiO and Si emissions from the interface and the following incorporation into the SiO{sub 2} and/or substrate. Classical molecular dynamics (MD) simulations with variable charge interatomic potentials are performed to clarify these atomic processes. By incorporating oxygen atoms, two-folded Si atoms are formed after structural relaxation at the interface and are emitted as SiO molecules into SiO{sub 2}. The energy barrier of the SiO emission is estimated to be 1.20 eV on the basis of the enthalpy change in an MD simulation.more » The emitted SiO molecule is incorporated into the SiO{sub 2} network through a Si-O rebonding process with generating an oxygen vacancy. The energy barrier of the SiO incorporation is estimated to be 0.79–0.81 eV. The elementary process of oxygen vacancy diffusion leading to the complete SiO incorporation is also simulated, and the energy barriers are found to be relatively small, 0.71–0.79 eV. The energy changes of Si emissions into the substrate and SiO{sub 2} are estimated to be 2.97–7.81 eV, which are larger than the energy barrier of the SiO emission. This result suggests that, at the ideally flat Si/SiO{sub 2} interface, the SiO emission into the SiO{sub 2} region occurs prior to the Si emission, which is consistent with previous theoretical and experimental studies. The above mentioned typical atomic processes are successfully extracted from some (or one) of MD simulations among many trials in which a statistical procedure is partly employed. Our results give a unified understanding of Si oxidation processes from an atomistic point of view.« less
  • The role of thin-film interfaces in the near-ultraviolet absorption and pulsed-laser–induced damage was studied for ion-beam–sputtered and electron-beam–evaporated coatings comprised from HfO 2 and SiO 2 thin-film pairs. To separate contributions from the bulk of the film and from interfacial areas, absorption and damage-threshold measurements were performed for a one-wave (355-nm wavelength) thick, HfO 2 single-layer film and for a film containing seven narrow HfO 2 layers separated by SiO 2 layers. The seven-layer film was designed to have a total optical thickness of HfO 2 layers, equal to one wave at 355 nm and an E-field peak and averagemore » intensity similar to a single-layer HfO 2 film. Absorption in both types of films was measured using laser calorimetry and photothermal heterodyne imaging. The results showed a small contribution to total absorption from thin-film interfaces, as compared to HfO 2 film material. The relevance of obtained absorption data to coating near-ultraviolet, nanosecond-pulse laser damage was verified by measuring the damage threshold and characterizing damage morphology. The results of this study revealed a higher damage resistance in the seven-layer coating as compared to the single-layer HfO 2 film in both sputtered and evaporated coatings. Here, the results are explained through the similarity of interfacial film structure with structure formed during the co-deposition of HfO 2 and SiO 2 materials.« less
  • Here, the role of thin-film interfaces in the near-ultraviolet (near-UV) absorption and pulsed laser-induced damage was studied for ion-beam-sputtered and electron-beam-evaporated coatings comprised from HfO 2 and SiO 2 thin-film pairs. To separate contributions from the bulk of the film and from interfacial areas, absorption and damage threshold measurements were performed for a one-wave (355-nm wavelength) thick, HfO 2 single-layer film and for a film containing seven narrow HfO 2 layers separated by SiO 2 layers. The seven-layer film was designed to have a total optical thickness of HfO 2 layers, equal to one wave at 355 nm and anmore » E-field peak and average intensity similar to a single-layer HfO 2 film. Absorption in both types of films was measured using laser calorimetry and photothermal heterodyne imaging. The results showed a small contribution to total absorption from thin-film interfaces as compared to HfO 2 film material. The relevance of obtained absorption data to coating near-UV, nanosecond-pulse laser damage was verified by measuring the damage threshold and characterizing damage morphology. The results of this study revealed a higher damage resistance in the seven-layer coating as compared to the single-layer HfO 2 film in both sputtered and evaporated coatings. The results are explained through the similarity of interfacial film structure with structure formed during the codeposition of HfO 2 and SiO 2 materials.« less
  • We compare the charging response of rapid thermally annealed (800 and 1000 deg. C) 4 nm thick HfO{sub 2} to as-deposited HfO{sub 2} on Si by measuring the surface potential of the HfO{sub 2} layers after vacuum ultraviolet (VUV) irradiation with 11.6 eV photons. From VUV spectroscopy, we determined all HfO{sub 2} layers show the presence of oxygen-interstitial defects (OIDs). The electronic states of OID in HfO{sub 2} line up in energy with oxygen-deficient Si centers within the SiO{sub 2} interfacial layer. This implies charge exchange between OIDs within HfO{sub 2} and the O-deficient silicon centers within the SiO{sub 2}more » interfacial layer are very important for controlling the radiation-induced trapped charge in HfO{sub 2} dielectric stacks.« less
  • Oxygen gettering by Ti overlayer (2-8 nm) on a HfO{sub 2}(3 nm)/SiO{sub 2}(1.5 nm)/Si(001) structure was investigated using high-resolution Rutherford backscattering spectroscopy. After deposition of a thin Ti layer, the interfacial SiO{sub 2} layer is reduced by {approx}0.2 nm and the released oxygen is incorporated in Ti layer. Subsequent annealing at 330 deg. C in UHV causes further reduction by 0.1-0.8 nm depending on the Ti layer thickness. In addition to the reduction of the SiO{sub 2} layer, significant oxygen depletion in the HfO{sub 2} layer was observed for thicker Ti layers after annealing.