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Due to its ferroelectricity, hafnium oxide has attracted a lot of attention for ferroelectric memory devices. Amongst different dopant elements, zirconium is found to be beneficial due to the relatively low crystallization temperature of hafnium‐zirconium‐oxide (HZO), thus it is back‐end‐of‐line (BEoL) compatible. The thickness of HZO has a significant impact on ferroelectric device reliability. High operation temperatures and high endurance are important criteria depending on the application. Herein, various HZO thicknesses (7, 8, and 10 nm) in MFM (metal‐ferroelectric‐metal) capacitors are investigated at varying operation temperatures (25 to 175 °C) at varying electric fields (±3 to ±5.4 MV cm−1) with respect to polarization, leakage current, endurance, and retention. 7 nm HZO showed promising results with an endurance of 107 cycles, with a low leakage current density, and almost no retention loss after 10 years. Extrapolated results at operation conditions (±2 MV cm−1 and 10 MHz) showed an endurance of 1010 cycles. [ABSTRACT FROM AUTHOR]

In this article, we present the capacitance–voltage (${C}$ – ${V}$) characteristics of HfxZr1−xO2 metal–ferroelectric–metal (MFM) thin-film capacitors with various Zr doping, thicknesses, and annealing temperatures. The influence of doping, electric field cycling, and annealing temperature on tuning characteristics (tunability) was analyzed and an optimized bias region for the maximum tunability was defined. Additional focus was made on an antiferroelectric-like (AFE) behavior, which occurs for > 50% Zr doping. The presence of both the ferroelectric and the AFE phase manifests itself in specific ${C}$ – ${V}$ behavior, where a reduced bias range is required for tuning, however, at the cost of a smaller tunability. The suitability of this behavior for varactor applications is also discussed. [ABSTRACT FROM AUTHOR]

A microwave characterization at UHF band of a ferroelectric hafnium zirconium oxide metal-ferroelectric-metal (MFM) capacitors for varactor applications has been performed. By using an impedance reflectivity method, a complex dielectric permittivity was obtained at frequencies up to 500 MHz. Ferroelectric Hf0.5Zr0.5O2 of 10 nm thickness has demonstrated a stable permittivity switching in the whole frequency range. A constant increase of the calculated dielectric loss is observed, which is shown to be an effect of electric field distribution on highly resistive titanium nitride (TiN) thin film electrodes. The C-V characteristics of a "butterfly" shape was also extracted, where the varactors exhibited a reduction of capacitance tunability from 18.6% at 10 MHz to 15.4% at 500 MHz. [ABSTRACT FROM AUTHOR]