Chemical Stability of IrO$_{2}$ Top Electrodes in Ferroelectric Hf$_{0.5}$Zr$_{0.5}$O$_{2}$ ‐Based Metal–Insulator–Metal Structures: The Impact of Annealing Gas

Autor: Szyjka, Thomas, Baumgarten, Lutz, Mittmann, Terence, Matveev, Yury, Schlueter, Christoph, Mikolajick, Thomas, Schroeder, Uwe, Mueller, Martina
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Physica status solidi / Rapid research letters 15(5), 2100027-(2021). doi:10.1002/pssr.202100027
DOI: 10.1002/pssr.202100027
Popis: Physica status solidi / Rapid research letters 15(5), 2100027 - (2021). doi:10.1002/pssr.202100027
The IrO$_{2}$ top electrode chemistry of ferroelectric IrO$_{2}$/Hf$_{0.5}$Zr$_{0.5}$O$_{2}$ (HZO)/IrO$_{2}$ metal–insulator–metal (MIM) structures dependent on rapid thermal annealing in different gas atmospheres (nitrogen, oxygen, and forming gas [FG]) is investigated. Using hard X-ray photoelectron spectroscopy (HAXPES), the strongly modified chemical states of the IrO$_{2}$ layer dependent on the choice of annealing gas atmosphere are observed. For O$_{2}$ and N$_{2}$ anneals, the IrO$_2$ electrode remains either unaffected or is just slightly chemically attacked at the top. In contrast, FG annealing causes a complete reduction of the IrO$_{2}$ top electrode into metallic Ir. Surprisingly, oxygen is detected—unbound to Ir—which is incorporated in the metallic Ir layer. This mobile oxygen is thought to affect the electrical behavior of the IrO$_{2}$/HZO/IrO$_{2}$ device. In addition, it may serve as a test sample for future studies of the root causes of the role of oxygen-vacancy interactions at the interface, which can influence the performance instabilities in HZO-based MIM structures, such as wake-up, imprint, and fatigue.
Published by Wiley-VCH, Weinheim
Databáze: OpenAIRE