Skip to main content

Lund University Publications

LUND UNIVERSITY LIBRARIES

Time-resolved ambient pressure x-ray photoelectron spectroscopy : Advancing the operando study of ALD chemistry

Jones, Rosemary LU ; Kokkonen, Esko LU orcid ; Eads, Calley LU orcid ; Küst, Ulrike K. LU orcid ; Prumbs, Julia LU ; Knudsen, Jan LU and Schnadt, Joachim LU orcid (2025) In Surface Science 753.
Abstract

Today, atomic layer deposition (ALD) has become a firm corner stone of thin film deposition technology. The microelectronics industry, an early adopter of ALD, imposes stringent requirements on ALD to produce films with highly defined physical and chemical properties, which becomes even more important as device and component dimensions decrease. This, in turn, means that our understanding of the chemical processes underlying ALD needs to increase exponentially. Here, we show that one can use synchrotron-based time-resolved ambient pressure x-ray photoelectron spectroscopy (APXPS) to obtain highly detailed operando information on the surface chemistry of ALD, not only, as proven earlier, during the initial ALD cycles, but also for the... (More)

Today, atomic layer deposition (ALD) has become a firm corner stone of thin film deposition technology. The microelectronics industry, an early adopter of ALD, imposes stringent requirements on ALD to produce films with highly defined physical and chemical properties, which becomes even more important as device and component dimensions decrease. This, in turn, means that our understanding of the chemical processes underlying ALD needs to increase exponentially. Here, we show that one can use synchrotron-based time-resolved ambient pressure x-ray photoelectron spectroscopy (APXPS) to obtain highly detailed operando information on the surface chemistry of ALD, not only, as proven earlier, during the initial ALD cycles, but also for the steady-growth regime reached during the later stages of deposition. Using event averaging and Fourier-transform methods, we show that the ALD of TiO2 from titanium tetraisopropoxide (TTIP) and water precursors in the steady-growth regime follows the suggested ligand-exchange reaction mechanism, with no sign of oxygen transport between the deposited layers and the bulk of the film, as has been observed for other materials systems. Hence, the TiO2 ALD from TTIP and water constitutes a textbook example of metal oxide ALD, as expected for this well-known ALD process. The detailed insight is made possible by computerised control of the precursor pulses that enable the recording of long data sets, which comprise many ALD cycles at highly regular intervals, in combination with an advanced data analysis that allows us to pick out signals undetectable in the raw data. The analysis method also allows to separate oscillating contributions to the signals induced by the ALD pulsing from the overwhelming bulk signal.

(Less)
Please use this url to cite or link to this publication:
author
; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Ambient pressure XPS, Atomic layer deposition, In situ, Operando, Time-resolved, TiO
in
Surface Science
volume
753
article number
122656
publisher
Elsevier
external identifiers
  • scopus:85210115109
ISSN
0039-6028
DOI
10.1016/j.susc.2024.122656
language
English
LU publication?
yes
additional info
Publisher Copyright: © 2024
id
2c8873cd-0ba8-40e8-8cd7-1890b5cb400e
date added to LUP
2024-12-02 14:40:03
date last changed
2025-05-06 02:04:54
@article{2c8873cd-0ba8-40e8-8cd7-1890b5cb400e,
  abstract     = {{<p>Today, atomic layer deposition (ALD) has become a firm corner stone of thin film deposition technology. The microelectronics industry, an early adopter of ALD, imposes stringent requirements on ALD to produce films with highly defined physical and chemical properties, which becomes even more important as device and component dimensions decrease. This, in turn, means that our understanding of the chemical processes underlying ALD needs to increase exponentially. Here, we show that one can use synchrotron-based time-resolved ambient pressure x-ray photoelectron spectroscopy (APXPS) to obtain highly detailed operando information on the surface chemistry of ALD, not only, as proven earlier, during the initial ALD cycles, but also for the steady-growth regime reached during the later stages of deposition. Using event averaging and Fourier-transform methods, we show that the ALD of TiO<sub>2</sub> from titanium tetraisopropoxide (TTIP) and water precursors in the steady-growth regime follows the suggested ligand-exchange reaction mechanism, with no sign of oxygen transport between the deposited layers and the bulk of the film, as has been observed for other materials systems. Hence, the TiO<sub>2</sub> ALD from TTIP and water constitutes a textbook example of metal oxide ALD, as expected for this well-known ALD process. The detailed insight is made possible by computerised control of the precursor pulses that enable the recording of long data sets, which comprise many ALD cycles at highly regular intervals, in combination with an advanced data analysis that allows us to pick out signals undetectable in the raw data. The analysis method also allows to separate oscillating contributions to the signals induced by the ALD pulsing from the overwhelming bulk signal.</p>}},
  author       = {{Jones, Rosemary and Kokkonen, Esko and Eads, Calley and Küst, Ulrike K. and Prumbs, Julia and Knudsen, Jan and Schnadt, Joachim}},
  issn         = {{0039-6028}},
  keywords     = {{Ambient pressure XPS; Atomic layer deposition; In situ; Operando; Time-resolved; TiO}},
  language     = {{eng}},
  publisher    = {{Elsevier}},
  series       = {{Surface Science}},
  title        = {{Time-resolved ambient pressure x-ray photoelectron spectroscopy : Advancing the operando study of ALD chemistry}},
  url          = {{http://dx.doi.org/10.1016/j.susc.2024.122656}},
  doi          = {{10.1016/j.susc.2024.122656}},
  volume       = {{753}},
  year         = {{2025}},
}