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 language | English (US) |
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Pages (from-to) | 12340-12349 |
Number of pages | 10 |
Journal | ACS Applied Materials and Interfaces |
Volume | 14 |
Issue number | 10 |
DOIs | |
State | Published - 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