skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Strain-induced phase variation and dielectric constant enhancement of epitaxial Gd{sub 2}O{sub 3}

Abstract

One of the approaches for realizing advanced high k insulators for metal oxide semiconductor field effect transistors based devices is the use of rare earth oxides. When these oxides are deposited as epitaxial thin films, they demonstrate dielectric properties that differ greatly from those that are known for bulk oxides. Using structural and spectroscopic techniques, as well as first-principles calculations, Gd{sub 2}O{sub 3} films deposited on Si (111) and Ge (111) were characterized. It was seen that the same 4 nm thick film, grown simultaneously on Ge and Si, presents an unstrained lattice on Ge while showing a metastable phase on Si. This change from the cubic lattice to the distorted metastable phase is characterized by an increase in the dielectric constant of more than 30% and a change in band gap. The case in study shows that extreme structural changes can occur in ultra-thin epitaxial rare earth oxide films and modify their dielectric properties when the underlying substrate is altered.

Authors:
; ;  [1]; ; ;  [2]
  1. Department of Materials Science and Engineering, Technion–Israel Institute of Technology, Haifa 32000 (Israel)
  2. Institute of Electronic Materials and Devices, Leibniz University of Hannover, Schneiderberg 32, 30167 Hannover (Germany)
Publication Date:
OSTI Identifier:
22597848
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 120; Journal Issue: 1; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CUBIC LATTICES; DEPOSITS; DIELECTRIC MATERIALS; EPITAXY; FIELD EFFECT TRANSISTORS; GADOLINIUM OXIDES; GERMANIUM; PERMITTIVITY; RARE EARTHS; SEMICONDUCTOR MATERIALS; SILICON; STRAINS; SUBSTRATES; THIN FILMS

Citation Formats

Shekhter, P., E-mail: Pini@tx.technion.ac.il, Amouyal, Y., Eizenberg, M., Schwendt, D., Wietler, T. F., and Osten, H. J. Strain-induced phase variation and dielectric constant enhancement of epitaxial Gd{sub 2}O{sub 3}. United States: N. p., 2016. Web. doi:10.1063/1.4958301.
Shekhter, P., E-mail: Pini@tx.technion.ac.il, Amouyal, Y., Eizenberg, M., Schwendt, D., Wietler, T. F., & Osten, H. J. Strain-induced phase variation and dielectric constant enhancement of epitaxial Gd{sub 2}O{sub 3}. United States. doi:10.1063/1.4958301.
Shekhter, P., E-mail: Pini@tx.technion.ac.il, Amouyal, Y., Eizenberg, M., Schwendt, D., Wietler, T. F., and Osten, H. J. 2016. "Strain-induced phase variation and dielectric constant enhancement of epitaxial Gd{sub 2}O{sub 3}". United States. doi:10.1063/1.4958301.
@article{osti_22597848,
title = {Strain-induced phase variation and dielectric constant enhancement of epitaxial Gd{sub 2}O{sub 3}},
author = {Shekhter, P., E-mail: Pini@tx.technion.ac.il and Amouyal, Y. and Eizenberg, M. and Schwendt, D. and Wietler, T. F. and Osten, H. J.},
abstractNote = {One of the approaches for realizing advanced high k insulators for metal oxide semiconductor field effect transistors based devices is the use of rare earth oxides. When these oxides are deposited as epitaxial thin films, they demonstrate dielectric properties that differ greatly from those that are known for bulk oxides. Using structural and spectroscopic techniques, as well as first-principles calculations, Gd{sub 2}O{sub 3} films deposited on Si (111) and Ge (111) were characterized. It was seen that the same 4 nm thick film, grown simultaneously on Ge and Si, presents an unstrained lattice on Ge while showing a metastable phase on Si. This change from the cubic lattice to the distorted metastable phase is characterized by an increase in the dielectric constant of more than 30% and a change in band gap. The case in study shows that extreme structural changes can occur in ultra-thin epitaxial rare earth oxide films and modify their dielectric properties when the underlying substrate is altered.},
doi = {10.1063/1.4958301},
journal = {Journal of Applied Physics},
number = 1,
volume = 120,
place = {United States},
year = 2016,
month = 7
}
  • Cited by 2
  • A theoretical study of the possible variation of d-orbital occupancy while going from the rhombohedral bulk phase to the strain induced tetragonal phase of BiFeO{sub 3} thin film has been carried out. A possible existence of an intermediate spin (IS) state, S=3/2 and a low spin (LS) state, S=1/2 in the tetragonal phase has been predicted, thereby clearly establishing the role of strain behind the d-orbital occupancy.
  • Nanometer thick cubic HfO{sub 2} doped with 19 at. % Y{sub 2}O{sub 3} (YDH) epitaxial films were grown on GaAs (001) using molecular beam epitaxy. Structural studies determined the epitaxial orientation relationships between the cubic YDH films and GaAs to be (001){sub GaAs}//(001){sub YDH} and [100]{sub GaAs}//[100]{sub YDH}. The YDH structure is strain relaxed with a lattice constant of 0.5122 nm with a small mosaic spread of 0.023 deg. and a twist angle of 2.9 deg. The YDH/GaAs interface is atomically abrupt without evidence of reacted interfacial layers. From C-V and I-V measurements a 7.7 nm thick YDH film hasmore » an enhanced dielectric constant {kappa}{approx}32, an equivalent oxide thickness of {approx}0.94 nm, an interfacial state density D{sub it}{approx}7x10{sup 12} cm{sup -2} eV{sup -1}, and a low leakage current density of 6x10{sup -5} A/cm{sup 2} at 1 V gate bias.« less
  • We report here the strain dependent structural and electrical transport properties of epitaxial NdNiO{sub 3} thin films. Pulsed laser deposition technique was used to grow the NdNiO{sub 3} thin films on c-axis oriented SrTiO{sub 3} single crystals. Deposited films were irradiated using 200 MeV Ag{sup 15+} ion beam at the varying fluence (1 Multiplication-Sign 10{sup 11}, 5 Multiplication-Sign 10{sup 11}, and 1 Multiplication-Sign 10{sup 12} ions/cm{sup 2}). X-ray diffraction studies confirm the epitaxial growth of the deposited films, which is maintained even up to the highest fluence. Rise in the in-plane compressive strain has been observed after the irradiation. Allmore » the films exhibit metal-insulator transition, however, a systematic decrease in the transition temperature (T{sub MI}) has been observed after irradiation, which may be attributed to the increase in the in-plane compression. Raman spectroscopy data reveal that this reduction in T{sub MI}, with the irradiation, is related to the decrease in band gap due to the stress generated by the in-plane compressive strain.« less