Role of Fluoride Doping in Low-Temperature Combustion-Synthesized ZrOₓ Dielectric Films
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.
A. Sil et al., "Role of Fluoride Doping in Low-Temperature Combustion-Synthesized ZrOₓ Dielectric Films," ACS Applied Materials and Interfaces, vol. 14, no. 10, pp. 12340 - 12349, American Chemical Society (ACS), Mar 2022.
The definitive version is available at https://doi.org/10.1021/acsami.1c22853
Keywords and Phrases
Combustion Synthesis; Fluoride Doping; High-Κ Dielectrics; Metal Oxides; Zirconium Oxide
International Standard Serial Number (ISSN)
Article - Journal
© 2022 American Chemical Society (ACS), All rights reserved.
16 Mar 2022
The authors 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.