Local Environment of Sc and Y Dopant Ions in Aluminum Nitride Thin Films

Asaf Cohen, Junying Li, Hagai Cohen, Ifat Kaplan-Ashiri, Sergey Khodorov, Ellen J. Wachtel, Igor Lubomirsky, Anatoly I. Frenkel, David Ehre

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

The local environments of Sc and Y in predominantly ⟨002⟩ textured, Al1-xDoxN (Do = Sc, x = 0.25, 0.30 or Y, x = 0.25) sputtered thin films with wurtzite symmetry were investigated using X-ray absorption (XAS) and photoelectron (XPS) spectroscopies. We present evidence from the X-ray absorption fine structure (XAFS) spectra that, when x = 0.25, both Sc3+ and Y3+ ions are able to substitute for Al3+, thereby acquiring four tetrahedrally coordinated nitrogen ligands, i.e., coordination number (CN) of 4. On this basis, the crystal radius of the dopant species in the wurtzite lattice, not available heretofore, could be calculated. By modeling the scandium local environment, extended XAFS (EXAFS) analysis suggests that when x increases from 0.25 to 0.30, CN for a fraction of the Sc ions increases from 4 to 6, signaling octahedral coordination. This change occurs at a dopant concentration significantly lower than the reported maximum concentration of Sc (42 mol % Sc) in wurtzite (Al, Sc)N. XPS spectra provide support for our observation that the local environment of Sc in (Al, Sc)N may include more than one type of coordination.

Original languageEnglish
Pages (from-to)853-861
Number of pages9
JournalACS Applied Electronic Materials
Volume6
Issue number2
DOIs
StatePublished - 27 Feb 2024
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2024 The Authors. Published by American Chemical Society

Keywords

  • aluminum scandium nitride
  • aluminum yttrium nitride
  • piezoelectric
  • seeding layer
  • sputtering
  • texture

Fingerprint

Dive into the research topics of 'Local Environment of Sc and Y Dopant Ions in Aluminum Nitride Thin Films'. Together they form a unique fingerprint.

Cite this