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PE-ALD of lithium aluminum silicon oxide solid electrolyte layers using LiHMDS

Andreas Werbrouck UGent, Thomas Dobbelaere UGent, Felix Mattelaer UGent and Christophe Detavernier UGent (2017)
abstract
Energy storage is one of the key challenges of our time. Especially in the field of Li-ion batteries, there are several applications where the unique properties of ALD (pinhole-free and uniform deposition on complex substrates) could be advantageous. In the current work, ALD of lithium containing silicon oxides, aluminum oxides and mixtures thereof are investigated with a three-step process involving LiHMDS, oxygen plasma and TMA. We studied lithium ion conductivity of the resulting films, aiming for applications in solid state (3D) batteries or protective coatings on battery electrode materials. Hämäläinnen et al. [1] reported the use of LiHMDS as a precursor for lithium-containing films in 2012. This precursor is useful as a source of lithium because of its stability and low cost compared to other precursors [2], [3]. As the LiHMDS contains both lithium and silicon, it has the unique property that it can act both as a source of lithium as well as silicon, as demonstrated - again by Hämäläinnen and coworkers - with the deposition of amorphous lithium silicon oxide with ozone as reactant [4]. By replacing the ozone by an oxygen plasma, we were able to deposit similar, amorphous carbonfree films with a slightly higher growth rate (2.3 A/cycle). By addition of a third TMA step to this process we were able to control the Si/Al ratio of the films, since TMA seems able to selectively remove Si surface groups, leaving the Li content unaffected. Precursor saturation was demonstrated, and all films showed good conformality. The reaction mechanism was studied with QMS and in-situ ellipsometry. Once this process was optimized, films with varying Si/Al ratio were fabricated. Some surface poisoning was observed when mixing the processes with and without TMA, resulting in lower growth rate, but overall film quality remained good. The resulting films were critically evaluated as solid state electrolytes. Ionic conductivities were studied using a combination of impedance spectroscopy measurements with and without liquid electrolyte. A nonlinear variation of the conductivity was measured in the mixed films, with a maximum ionic conductivity of 5.7·10−7 S/cm, while electronic conductivity maintained as low as 7.9 · 10−12 S/cm. [1] J. Hämäläinen, J. Holopainen, F. Munnik, T. Hatanpää, M. Heikkilä, M. Ritala, M. Leskelä, J. Electrochem. Soc., (2012). [2] Erik Østreng, P. Vajeeston, O. Nilsen, H. Fjellvåg, RSC Adv., (2012). [3] M. Nisula, Y. Shindo, H. Koga, M. Karppinen, Chem. Mater., (2015). [4] J. Hämäläinen, F. Munnik, T. Hatanpää, J. Holopainen, M. Ritala, M. Leskelä, J. Vac. Sci. Technol. Vac. Surf. Films, (2012).
Please use this url to cite or link to this publication:
author
organization
year
type
conference
publication status
published
subject
conference name
Baltic ALD
conference location
Linköping, Sweden
UGent publication?
yes
classification
U
id
8536397
handle
http://hdl.handle.net/1854/LU-8536397
date created
2017-11-07 11:39:37
date last changed
2017-11-13 14:19:16
@inproceedings{8536397,
  abstract     = {Energy storage is one of the key challenges of our time. Especially in the field of Li-ion batteries,
there are several applications where the unique properties of ALD (pinhole-free and uniform
deposition on complex substrates) could be advantageous. In the current work, ALD of lithium containing silicon oxides, aluminum oxides and mixtures thereof are investigated with a three-step
process involving LiHMDS, oxygen plasma and TMA. We studied lithium ion conductivity of the
resulting films, aiming for applications in solid state (3D) batteries or protective coatings on battery
electrode materials.
H{\"a}m{\"a}l{\"a}innen et al. [1] reported the use of LiHMDS as a precursor for lithium-containing films in
2012. This precursor is useful as a source of lithium because of its stability and low cost compared to
other precursors [2], [3]. As the LiHMDS contains both lithium and silicon, it has the unique property
that it can act both as a source of lithium as well as silicon, as demonstrated - again by H{\"a}m{\"a}l{\"a}innen
and coworkers - with the deposition of amorphous lithium silicon oxide with ozone as reactant [4].
By replacing the ozone by an oxygen plasma, we were able to deposit similar, amorphous carbonfree films with a slightly higher growth rate (2.3 A/cycle). By addition of a third TMA step to this
process we were able to control the Si/Al ratio of the films, since TMA seems able to selectively
remove Si surface groups, leaving the Li content unaffected. Precursor saturation was
demonstrated, and all films showed good conformality. The reaction mechanism was studied with
QMS and in-situ ellipsometry.
Once this process was optimized, films with varying Si/Al ratio were fabricated. Some surface
poisoning was observed when mixing the processes with and without TMA, resulting in lower growth
rate, but overall film quality remained good. The resulting films were critically evaluated as solid
state electrolytes. Ionic conductivities were studied using a combination of impedance spectroscopy
measurements with and without liquid electrolyte. A nonlinear variation of the conductivity was
measured in the mixed films, with a maximum ionic conductivity of 5.7{\textperiodcentered}10\ensuremath{-}7 S/cm, while
electronic conductivity maintained as low as 7.9 {\textperiodcentered} 10\ensuremath{-}12 S/cm.

[1]\unmatched{0009}J. H{\"a}m{\"a}l{\"a}inen, J. Holopainen, F. Munnik, T. Hatanp{\"a}{\"a}, M. Heikkil{\"a}, M. Ritala, M. Leskel{\"a}, J. Electrochem. Soc., (2012).
[2]\unmatched{0009}Erik {\O}streng, P. Vajeeston, O. Nilsen, H. Fjellv{\aa}g, RSC Adv., (2012).
[3]\unmatched{0009}M. Nisula, Y. Shindo, H. Koga, M. Karppinen, Chem. Mater., (2015).
[4]\unmatched{0009}J. H{\"a}m{\"a}l{\"a}inen, F. Munnik, T. Hatanp{\"a}{\"a}, J. Holopainen, M. Ritala, M. Leskel{\"a}, J. Vac. Sci. Technol. Vac. Surf. Films, (2012).

},
  author       = {Werbrouck, Andreas and Dobbelaere, Thomas and Mattelaer, Felix and Detavernier, Christophe},
  location     = {Link{\"o}ping, Sweden},
  title        = {PE-ALD of lithium aluminum silicon oxide solid electrolyte layers using LiHMDS},
  year         = {2017},
}

Chicago
Werbrouck, Andreas, Thomas Dobbelaere, Felix Mattelaer, and Christophe Detavernier. 2017. “PE-ALD of Lithium Aluminum Silicon Oxide Solid Electrolyte Layers Using LiHMDS.” In .
APA
Werbrouck, A., Dobbelaere, T., Mattelaer, F., & Detavernier, C. (2017). PE-ALD of lithium aluminum silicon oxide solid electrolyte layers using LiHMDS. Presented at the Baltic ALD.
Vancouver
1.
Werbrouck A, Dobbelaere T, Mattelaer F, Detavernier C. PE-ALD of lithium aluminum silicon oxide solid electrolyte layers using LiHMDS. 2017.
MLA
Werbrouck, Andreas, Thomas Dobbelaere, Felix Mattelaer, et al. “PE-ALD of Lithium Aluminum Silicon Oxide Solid Electrolyte Layers Using LiHMDS.” 2017. Print.