Role of Fluoride Doping in Low-Temperature Combustion-Synthesized ZrOxDielectric Films

Aritra Sil, Elise A. Goldfine, Wei Huang, Michael J. Bedzyk, Julia E. Medvedeva, Antonio Facchetti

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Zirconium oxide (ZrOx) is an attractive metal oxide dielectric material for low-voltage, optically transparent, and mechanically flexible electronic applications due to the high dielectric constant (κ ∼14-30), negligible visible light absorption, and, as a thin film, good mechanical flexibility. In this contribution, we explore the effect of fluoride doping on structure-property-function relationships in low-temperature solution-processed amorphous ZrOx. Fluoride-doped zirconium oxide (F:ZrOx) films with a fluoride content between 1.7 and 3.2 in atomic (at) % were synthesized by a combustion synthesis procedure. Irrespective of the fluoride content, grazing incidence X-ray diffraction, atomic-force microscopy, and UV-vis spectroscopy data indicate that all F:ZrOx films are amorphous, atomically smooth, and transparent in visible light. Impedance spectroscopy measurements reveal that unlike solution-processed fluoride-doped aluminum oxide (F:AlOx), fluoride doping minimally affects the frequency-dependent capacitance instability of solution-processed F:ZrOx films. This result can be rationalized by the relatively weak Zr-F versus Zr-O bonds and the large ionic radius of Zr+4, as corroborated by EXAFS analysis and MD simulations. Nevertheless, the performance of pentacene thin-film transistors (TFTs) with F:ZrOx gate dielectrics indicates that fluoride incorporation reduces I-V hysteresis in the transfer curves and enhances bias stress stability versus TFTs fabricated with analogous, but undoped ZrOx films as gate dielectrics, due to reduced trap density.

Original languageEnglish (US)
Pages (from-to)12340-12349
Number of pages10
JournalACS Applied Materials and Interfaces
Volume14
Issue number10
DOIs
StatePublished - Mar 16 2022

Funding

We thank the Northwestern U. MRSEC grant NSF-DMR 1720139 for support of this research. J.E.M. thanks NSF-DMREF grants 1729779 and DMR-1842467 for support and NSF-MRI grant OAC-1919789 for computational facilities. This work made use of the EPIC, Keck-II, and/or SPID facility(ies) of Northwestern University’s NU ANCE Center, which has received support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205); the MRSEC program (NSF DMR-1720139) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN. XRR measurements used the Jerome B. The Cohen X-Ray Diffraction Facility also supported by the NSF MRSEC and SHyNE resource. This work used the 5-BM-D beamline of the DuPont-Northwestern-Dow Collaborative Access Team (DND-CAT) located at Sector 5 of the Advanced Photon Source (APS). DND-CAT is supported by Northwestern University (NU), E.I. DuPont de Nemours & Co., and the Dow Chemical Company. Special thanks to Qing Ma for EXAFS measurements conducted during remote operation of the APS. This research used resources of the APS, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under contract no. DE-AC02-06CH11357.

Keywords

  • combustion synthesis
  • fluoride doping
  • high-κ dielectrics
  • metal oxides
  • zirconium oxide

ASJC Scopus subject areas

  • General Materials Science

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