Influence of co-reactants on surface passivation by nanoscale hafnium oxide layers grown by atomic layer deposition on silicon

Abstract: Hafnium oxide thin films have attracted considerable interest for passivation layers, protective barriers, and anti-reflection coatings. Atomic layer deposition offers a route to produce conformal films at the nanometre scale, but there is a lack of clarity over how the growth conditions affect the film properties. Here we present a study into the role of different atomic layer deposition co-reactants (O2 plasma, O3 and H2O) in the growth of HfOx on n-type silicon from a tetrakis(dimethylamido)hafnium (TDMAH) precursor followed by post-deposition annealing (up to 500 °C). Through X-ray diffraction and X-ray photoelectron spectroscopy, we demonstrate variations in film composition, stoichiometry and crystallinity with co-reactant. Depth profiling conducted with X-ray photoelectron spectroscopy reveals differences in composition between the HfOx surface and the HfOx/Si interface. We also determine differences in fixed charge density and chemical passivation through photoconductance decay measurements and Kelvin probe analysis. We find surface recombination velocities (SRVs) <10 cm s−1 are possible for HfOx films, with the best passivation achieved for H2O-based HfOx (SRVs as low as ∼5 cm s−1). With TDMAH as a hafnium precursor, we show that neither co-reactant choice nor annealing environment influence the resulting charge polarity

Object Details

• Location: Deutsche Nationalbibliothek Frankfurt am Main
• Extent: Online-Ressource
• Language: Englisch
• Notes: RSC applied interfaces. - 1, 3 (2024) , 471-482, ISSN: 2755-3701

Contributors, Places and Time

• Event: Veröffentlichung
• (where): Freiburg
• (who): Universität
• (when): 2024
• Creator: Pain, Sophie L. ; Khorani, Edris ; Yadav, Anup ; Niewelt, Tim ; Leimenstoll, Antonio ; Healy, Brendan F. M. ; Walker, Marc ; Walker, David Johannes ; Grant, Nicholas Ewen ; Murphy, John D.
• Contributor: Albert-Ludwigs-Universität Freiburg. Institut für Nachhaltige Technische Systeme ; Albert-Ludwigs-Universität Freiburg. Professur für Photovoltaische Energiekonversion ; Fraunhofer-Institut für Solare Energiesysteme

Further information

• DOI: 10.1039/d3lf00210a
• URN: urn:nbn:de:bsz:25-freidok-2459915
• Rights: Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Last update: 25.03.2025, 1:42 PM CET