Ambient pressure x-ray photoelectron spectroscopy setup for synchrotron-based in situ and operando atomic layer deposition research

Funding Information: The ALD cell is a result of collaboration between the University of Helsinki (Finland) and the MAX IV Laboratory and funded by the Faculty of Science, University of Helsinki and Academy of Finland (Grant No. 295696) under the operations collaboration agreement between Finland (FIMAX consortium) and the MAX IV Laboratory. Research conducted at MAX IV, a Swedish national user facility, is supported by the Swedish Research Council under Contract No. 2018-07152, the Swedish Governmental Agency for Innovation Systems under Contract No. 2018-04969, and Formas under Contract No. 2019-02496. M.P. acknowledges funding from the Academy of Finland by the profiling action on Matter and Materials (Grant No. 318913). M.R. acknowledges funding from the Academy of Finland (Grant No. 309552). J.S. acknowledges funding from Vetenskapsrådet (Swedish Research Council) under Grant No. 2017-03871. The authors thank the MAX IV staff and especially Mikko-Heikki Mikkelä and Jörgen Hellborg for help in the design, construction, and testing of the ALD cell. Publisher Copyright: © 2022 Author(s).An ambient pressure cell is described for conducting synchrotron-based x-ray photoelectron spectroscopy (XPS) measurements during atomic layer deposition (ALD) processes. The instrument is capable of true in situ and operando experiments in which it is possible to directly obtain elemental and chemical information from the sample surface using XPS as the deposition process is ongoing. The setup is based on the ambient pressure XPS technique, in which sample environments with high pressure (several mbar) can be created without compromising the ultrahigh vacuum requirements needed for the operation of the spectrometer and the synchrotron beamline. The setup is intended for chemical characterization of the surface intermediates during the initial stages of the deposition processes. The SPECIES beamline and the ALD cell provide a unique experimental platform for obtaining new information on the surface chemistry during ALD half-cycles at high temporal resolution. Such information is valuable for understanding theALD reaction mechanisms and crucial in further developing and improving ALD processes. We demonstrate the capabilities of the setup by studying the deposition of TiO2 on a SiO2 surface by using titanium(IV) tetraisopropoxide and water as precursors. Multiple core levels and the valence band of the substrate surface were followed during the film deposition using ambient pressure XPS.Peer reviewe