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Title: In-situ spectroscopic ellipsometry and structural study of HfO{sub 2} thin films deposited by radio frequency magnetron sputtering

Abstract

We have investigated the reduction of unwanted interfacial SiO{sub 2} layer at HfO{sub 2}/Si interface brought about by the deposition of thin Hf metal buffer layer on Si substrate prior to the deposition of HfO{sub 2} thin films for possible direct contact between HfO{sub 2} thin film and Si substrate, necessary for the future generation devices based on high-κ HfO{sub 2} gate dielectrics. Reactive rf magnetron sputtering system along with the attached in-situ spectroscopic ellipsometry (SE) was used to predeposit Hf metal buffer layer as well as to grow HfO{sub 2} thin films and also to undertake the in-situ characterization of the high-κ HfO{sub 2} thin films deposited on n-type 〈100〉 crystalline silicon substrate. The formation of the unwanted interfacial SiO{sub 2} layer and its reduction due to the predeposited Hf metal buffer layer as well as the depth profiling and also structure of HfO{sub 2} thin films were investigated by in-situ SE, Fourier Transform Infrared spectroscopy, and Grazing Incidence X-ray Diffraction. The study demonstrates that the predeposited Hf metal buffer layer has played a crucial role in eliminating the formation of unwanted interfacial layer and that the deposited high-κ HfO{sub 2} thin films are crystalline although they were depositedmore » at room temperature.« less

Authors:
;  [1];  [2]
  1. Department of Physics, Izmir Institute of Technology (IZTECH), Urla, 35430 Izmir (Turkey)
  2. Department of Physics, Utkal University, Bhubaneswar 751004 (India)
Publication Date:
OSTI Identifier:
22314333
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 8; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; DEPOSITS; ELLIPSOMETRY; HAFNIUM OXIDES; HYDROFLUORIC ACID; LAYERS; MAGNETRONS; METALS; RADIOWAVE RADIATION; SILICA; SILICON; SILICON OXIDES; SPUTTERING; SUBSTRATES; TEMPERATURE RANGE 0273-0400 K; THIN FILMS; X-RAY DIFFRACTION

Citation Formats

Cantas, Ayten, Aygun, Gulnur, E-mail: gulnuraygun@iyte.edu.tr, and Basa, Deepak Kumar. In-situ spectroscopic ellipsometry and structural study of HfO{sub 2} thin films deposited by radio frequency magnetron sputtering. United States: N. p., 2014. Web. doi:10.1063/1.4893708.
Cantas, Ayten, Aygun, Gulnur, E-mail: gulnuraygun@iyte.edu.tr, & Basa, Deepak Kumar. In-situ spectroscopic ellipsometry and structural study of HfO{sub 2} thin films deposited by radio frequency magnetron sputtering. United States. doi:10.1063/1.4893708.
Cantas, Ayten, Aygun, Gulnur, E-mail: gulnuraygun@iyte.edu.tr, and Basa, Deepak Kumar. Thu . "In-situ spectroscopic ellipsometry and structural study of HfO{sub 2} thin films deposited by radio frequency magnetron sputtering". United States. doi:10.1063/1.4893708.
@article{osti_22314333,
title = {In-situ spectroscopic ellipsometry and structural study of HfO{sub 2} thin films deposited by radio frequency magnetron sputtering},
author = {Cantas, Ayten and Aygun, Gulnur, E-mail: gulnuraygun@iyte.edu.tr and Basa, Deepak Kumar},
abstractNote = {We have investigated the reduction of unwanted interfacial SiO{sub 2} layer at HfO{sub 2}/Si interface brought about by the deposition of thin Hf metal buffer layer on Si substrate prior to the deposition of HfO{sub 2} thin films for possible direct contact between HfO{sub 2} thin film and Si substrate, necessary for the future generation devices based on high-κ HfO{sub 2} gate dielectrics. Reactive rf magnetron sputtering system along with the attached in-situ spectroscopic ellipsometry (SE) was used to predeposit Hf metal buffer layer as well as to grow HfO{sub 2} thin films and also to undertake the in-situ characterization of the high-κ HfO{sub 2} thin films deposited on n-type 〈100〉 crystalline silicon substrate. The formation of the unwanted interfacial SiO{sub 2} layer and its reduction due to the predeposited Hf metal buffer layer as well as the depth profiling and also structure of HfO{sub 2} thin films were investigated by in-situ SE, Fourier Transform Infrared spectroscopy, and Grazing Incidence X-ray Diffraction. The study demonstrates that the predeposited Hf metal buffer layer has played a crucial role in eliminating the formation of unwanted interfacial layer and that the deposited high-κ HfO{sub 2} thin films are crystalline although they were deposited at room temperature.},
doi = {10.1063/1.4893708},
journal = {Journal of Applied Physics},
number = 8,
volume = 116,
place = {United States},
year = {Thu Aug 28 00:00:00 EDT 2014},
month = {Thu Aug 28 00:00:00 EDT 2014}
}
  • Radio-frequency magnetron sputtering was used to deposit SrBi{sub 2}Ta{sub 2}O{sub 9} ferroelectric thin films on Pt(111)/Ti/SiO{sub 2}/Si(001) substrates. Thin films were deposited at room temperature with argon pressures of 0.5{endash}100 mTorr and with sputtering power of 2.5 W/cm{sup 2}. The crystal orientations of thin films were strongly affected by the argon pressures, the {ital c}-axis oriented SrBi{sub 2}Ta{sub 2}O{sub 9} thin film was obtained with argon pressure of 30 mTorr. The crystal structures of the {ital c}-axis oriented SrBi{sub 2}Ta{sub 2}O{sub 9} thin film were investigated by x-ray diffraction methods: {theta}-2{theta} scan, rocking curve, and {phi} scans. The well alignedmore » microstructure was observed with the average grain size of about 2000 A in an atomic force microscopic image. Ferroelectric properties were observed for the {ital c}-axis oriented thin film: {ital P}{sub {ital r}}{sup {asterisk}}{minus}{ital P}{sub {ital r}}{sup {Lambda}} and {ital E}{sub {ital c}} were 9.7 {mu}C/cm{sup 2} and 50 kV/cm, respectively, with excitation voltage of 3 V. {copyright} {ital 1996 American Institute of Physics.}« less
  • Lanthanum oxide (La{sub 2}O{sub 3}) films were grown by the reactive dc magnetron sputtering and studied their structural, chemical and optical parameters. La{sub 2}O{sub 3} films were deposited onto Si substrates by sputtering La-metal in a reactive gas (Ar+O{sub 2}) mixture at a substrate temperature of 200 deg. C Reflection high-energy electron diffraction measurements confirm the amorphous state of La{sub 2}O{sub 3} films. Chemical analysis of the top-surface layers evaluated with x-ray photoelectron spectroscopy indicates the presence of a layer modified by hydroxylation due to interaction with atmosphere. Optical parameters of a-La{sub 2}O{sub 3} were determined with spectroscopic ellipsometry (SE).more » There is no optical absorption over spectral range {lambda}=250-1100 nm. Dispersion of refractive index of a-La{sub 2}O{sub 3} was defined by fitting of SE parameters over {lambda}=250-1100 nm.« less
  • Thin films of yttrium oxide have been deposited onto substrates of zinc sulfide by rf magnetron and ion beam sputtering. The measured magnitude and the sign of the stresses in these films (interferometric Newton rings method) vary between 7 and 21 x 10/sup 9/ dyn/cm/sup 2/ and are found to be compressive. The relationship of the measured stress to various deposition parameters is explored. It is proposed that these compressive film stresses increase the flexural strength and apparent indentation fracture toughness of the ZnS substrates.
  • Spectroscopic ellipsometry with photon energy 0.75-6.5 eV at room temperature has been used to derive the optical properties of nitrogen-incorporated HfO{sub 2} films on Si(100) substrates grown by radio-frequency reactive sputtering using different N{sub 2}/(N{sub 2}+O{sub 2}+Ar) gas ratios from 20% to 50%. Excellent agreement has been found between the experimental and the simulated spectra, in which an empirical dielectric dispersion relation based on Tauc-Lorentz model has been successfully adopted. Increases in the refractive index n and the extinction coefficient. k, with increases in nitrogen-incorporation content are observed due to the nitrogen-incorporation-induced higher packing density. The change of the complexmore » dielectric functions and reduction in the optical band gap with an increase in nitrogen concentration resulting from the effect of the nitrogen-incorporation on the structure are discussed in detail.« less
  • We report on highly crystalline zinc nitride (Zn{sub 3}N{sub 2}) thin films which were grown by rf magnetron sputtering on quartz substrates. The substrate temperature during growth is found to strongly affect the crystal quality of the thin films. The chemical bonding states were determined by x-ray photoelectron spectroscopy. Large chemical shifts in core-level N 1s peaks with binding energy of 396.4 eV were observed as compared to N 1s of free amine (398.8 eV), indicating Zn-N bond formation. Two N 1s states were found: one is N{sub 1} formed by Zn-N bonds and another is (N{sub 2}) produced bymore » substitution of N molecules at N ion sites, which leads to larger lattice constants, consistent with x-ray diffraction results. Temperature-dependent Hall effect measurements of our Zn{sub 3}N{sub 2} films exhibited distinct conduction mechanisms at specific different temperature ranges.« less