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A model-based methodology for the analysis and design of atomic layer deposition processes-Part II: Experimental validation and mechanistic analysis

Holmqvist, Anders LU ; Torndahl, T. and Stenström, Stig LU (2013) In Chemical Engineering Science 94. p.316-329
Abstract
This paper demonstrates the experimental validation and mechanistic analysis of the continuous cross-flow atomic layer deposition (ALD) reactor model developed in the first article of this series (Holmqvist et al., in press). A general nonlinear parameter estimation problem was formulated to identify the kinetic parameters involved in the developed ALD gassurface reaction mechanism, governing ZnO film growth, from ex situ film thickness measurements. The presented methodology for comprehensive model assessment considers the statistical uncertainty of least-squares estimates and its ultimate impact on the model predicted response. Joint inference regions were determined to assess the significance of parameter estimates and results indicate... (More)
This paper demonstrates the experimental validation and mechanistic analysis of the continuous cross-flow atomic layer deposition (ALD) reactor model developed in the first article of this series (Holmqvist et al., in press). A general nonlinear parameter estimation problem was formulated to identify the kinetic parameters involved in the developed ALD gassurface reaction mechanism, governing ZnO film growth, from ex situ film thickness measurements. The presented methodology for comprehensive model assessment considers the statistical uncertainty of least-squares estimates and its ultimate impact on the model predicted response. Joint inference regions were determined to assess the significance of parameter estimates and results indicate that all estimates involved in the precursor half-reactions were adequately determined. The reparameterization of the Arrhenius equation effectively decreased the characteristically high correlations between Arrhenius parameters, leading to improvement in precision of individual parameter estimates. Model predictions of the spatially dependent film thickness profile with narrow confidence band were in good agreement with both calibration and validation experimental data, respectively, under a wide range of operating conditions. The subsequent extensive theoretical analysis exhibits that the experimentally validated model successfully reproduces the detailed process dynamics revealed by in situ quartz crystal microbalance and quadrupole mass spectroscopy diagnostics, and thereby provides a supplementary analysis tool. Finally, the univariate sensitivity analysis revealed the mechanistic dependence of all the measured process operating parameters on the spatially dependent film thickness profile, resolved at the level of a single pulse sequence. Hence, the presented model-based framework serves as a means to guide future research efforts in the field of ALD process optimization. (c) 2012 Elsevier Ltd. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Atomic layer deposition, Experimental model validation, Parameter, identification, Optimisation, Dynamic simulation, Kinetics
in
Chemical Engineering Science
volume
94
pages
316 - 329
publisher
Elsevier
external identifiers
  • wos:000318613200032
  • scopus:84876736811
ISSN
0009-2509
DOI
10.1016/j.ces.2012.06.063
language
English
LU publication?
yes
id
b515b972-8dbd-4129-8fe0-a55106bf724c (old id 3932555)
date added to LUP
2013-07-15 11:13:04
date last changed
2019-02-27 02:30:05
@article{b515b972-8dbd-4129-8fe0-a55106bf724c,
  abstract     = {This paper demonstrates the experimental validation and mechanistic analysis of the continuous cross-flow atomic layer deposition (ALD) reactor model developed in the first article of this series (Holmqvist et al., in press). A general nonlinear parameter estimation problem was formulated to identify the kinetic parameters involved in the developed ALD gassurface reaction mechanism, governing ZnO film growth, from ex situ film thickness measurements. The presented methodology for comprehensive model assessment considers the statistical uncertainty of least-squares estimates and its ultimate impact on the model predicted response. Joint inference regions were determined to assess the significance of parameter estimates and results indicate that all estimates involved in the precursor half-reactions were adequately determined. The reparameterization of the Arrhenius equation effectively decreased the characteristically high correlations between Arrhenius parameters, leading to improvement in precision of individual parameter estimates. Model predictions of the spatially dependent film thickness profile with narrow confidence band were in good agreement with both calibration and validation experimental data, respectively, under a wide range of operating conditions. The subsequent extensive theoretical analysis exhibits that the experimentally validated model successfully reproduces the detailed process dynamics revealed by in situ quartz crystal microbalance and quadrupole mass spectroscopy diagnostics, and thereby provides a supplementary analysis tool. Finally, the univariate sensitivity analysis revealed the mechanistic dependence of all the measured process operating parameters on the spatially dependent film thickness profile, resolved at the level of a single pulse sequence. Hence, the presented model-based framework serves as a means to guide future research efforts in the field of ALD process optimization. (c) 2012 Elsevier Ltd. All rights reserved.},
  author       = {Holmqvist, Anders and Torndahl, T. and Stenström, Stig},
  issn         = {0009-2509},
  keyword      = {Atomic layer deposition,Experimental model validation,Parameter,identification,Optimisation,Dynamic simulation,Kinetics},
  language     = {eng},
  pages        = {316--329},
  publisher    = {Elsevier},
  series       = {Chemical Engineering Science},
  title        = {A model-based methodology for the analysis and design of atomic layer deposition processes-Part II: Experimental validation and mechanistic analysis},
  url          = {http://dx.doi.org/10.1016/j.ces.2012.06.063},
  volume       = {94},
  year         = {2013},
}