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Despite the many advantages afforded to the investigation of complex compositional systems by combinatorial sputtering, the application of this synthesis technique is hindered by high-throughput characterization bottlenecks. The recent application of translatable compositional and magnetic characterization techniques, such as precision Wavelength Dispersive X-ray Fluorescence (WDXRF) and Magneto-Optic Kerr Effect (MOKE), are enabling for full wafer mapping of film chemistry, magnetic moment, and coercivity, although under-applied. An example system that stands to benefit from the application of combinatorial sputtering and high-throughput characterization is lightly nitrided FexVyNz, which, among other doped FeN materials, is a candidate rare earth-free permanent magnet for electric motor and read/write head applications. Within this report, a combinatorial sputtering and characterization procedure, which leverages high-throughput WDXRF and MOKE mapping, is utilized to investigate the effects of V composition on the room temperature ferromagnetic properties of FexVyNz. Observations made using WDXRF and MOKE mapping are shown to closely agree with vibrating sample magnetometry and x-ray photoelectron spectroscopy measurements made on cleaved regions of interest from the parent wafer. It is observed that the inclusion of V deleteriously affects the saturated moment of FeN, resulting in complete macroscopic reduction at 18 at. %. A maximum film coercivity of 165 Oe is observed at 10 at. % V, likely contributed to by crystallographic texture due to processing, followed by a complete reduction along with the saturated moment. These observations support the high-throughput characterization approaches of WDXRF and MOKE to combinatorial synthesis workflows. [ABSTRACT FROM AUTHOR]

Biaxial stress is identified to play an important role in the polar orthorhombic phase stability in hafnium oxide‐based ferroelectric thin films. However, the stress state during various stages of wake‐up has not yet been quantified. In this work, the stress evolution with field cycling in hafnium zirconium oxide capacitors is evaluated. The remanent polarization of a 20 nm thick hafnium zirconium oxide thin film increases from 9.80 to 15.0 µC cm−2 following 106 field cycles. This increase in remanent polarization is accompanied by a decrease in relative permittivity that indicates that a phase transformation has occurred. The presence of a phase transformation is supported by nano‐Fourier transform infrared spectroscopy measurements and scanning transmission electron microscopy that show an increase in ferroelectric phase content following wake‐up. The stress of individual devices field cycled between pristine and 106 cycles is quantified using the sin2(ψ) technique, and the biaxial stress is observed to decrease from 4.3 ± 0.2 to 3.2 ± 0.3 GPa. The decrease in stress is attributed, in part, to a phase transformation from the antipolar Pbca phase to the ferroelectric Pca21 phase. This work provides new insight into the mechanisms controlling and/or accompanying polarization wake‐up in hafnium oxide‐based ferroelectrics. [ABSTRACT FROM AUTHOR]

The mechanisms leading to wake-up and fatigue in ferroelectric hafnium zirconium oxide thin film devices with symmetric RuO2 electrodes are investigated via polarization, relative permittivity, dielectric nonlinearity, pyroelectric coefficient, and microfocus x-ray diffraction (XRD) measurements. The devices are observed to wake-up for up to 103 bipolar pulsed field cycles, after which fatigue occurs with polarization approaching zero following 108 cycles. Wake-up is accompanied by a decrease in both high-field permittivity and hysteresis loop pinching and an increase in the pyroelectric coefficient, indicating that the wake-up process involves a combination of transformations from the tetragonal to the orthorhombic phase and domain depinning from defect redistribution. Fatigue is observed to coincide with an increase in irreversible domain wall motion and a decrease in pyroelectric coefficient. Finite pyroelectric coefficients are measured on fully fatigued devices, indicating that domain pinning is a strong contributor to fatigue and that fatigued devices contain domain structures that are unable to switch under the fields applied for measurement. Microfocus XRD patterns measured on each device reveal that the phase constitution is qualitatively unaffected by field cycling and resultant polarization fatigue. These data indicate that the wake-up process has contributions from both phase transformations and domain depinning, whereas the fatigue process is driven primarily by domain pinning, and the near-zero measured switchable polarization is actually a poled device with immobile domains. These observations provide insight into the physical changes occurring during field cycling of HfO2-based ferroelectrics while examining a possible oxide electrode material for silicon CMOS device implementation. [ABSTRACT FROM AUTHOR]

While ferroelectric HfO2 shows promise for use in memory technologies, limited endurance is one factor that challenges its widespread application. Herein, endurance is investigated through field cycling W/Hf0.5Zr0.5O2/W capacitors above the coercive field while manipulating the time under field using bipolar pulses of varying pulse duration or duty cycle. Both remanent polarization and leakage current increase with increasing pulse duration. Additionally, an order of magnitude decrease in the pulse duration from 20 to 2 μs results in an increase in endurance lifetime of nearly two orders of magnitude from 3 × 106 to 2 × 108 cycles. These behaviors are attributed to increasing time under field allowing for charged oxygen vacancy migration, initially unpinning domains, or driving phase transformations before segregating to grain boundaries and electrode interfaces. This oxygen vacancy migration causes increasing polarization before creating conducting percolation paths that result in degradation and premature device failure. This process is suppressed for 2 μs pulse duration field cycling where minimal wake‐up and lower leakage before device failure are observed, suggesting that very short pulses can be used to significantly increase device endurance. These results provide insight into the impact of pulse duration on device performance and highlight consideration of use of conditions when endurance testing. [ABSTRACT FROM AUTHOR]

Composition dependence of second harmonic generation, refractive index, extinction coefficient, and optical bandgap in 20 nm thick crystalline Hf1−xZrxO2 (0 ≤ x ≤ 1) thin films is reported. The refractive index exhibits a general increase with increasing ZrO2 content with all values within the range of 1.98–2.14 from 880 nm to 400 nm wavelengths. A composition dependence of the indirect optical bandgap is observed, decreasing from 5.81 eV for HfO2 to 5.17 eV for Hf0.4Zr0.6O2. The bandgap increases for compositions with x > 0.6, reaching 5.31 eV for Hf0.1Zr0.9O2. Second harmonic signals are measured for 880 nm incident light. The magnitude of the second harmonic signal scales with the magnitude of the remanant polarization in the composition series. Film compositions that display near zero remanent polarizations exhibit minimal second harmonic generation while those with maximum remanent polarization also display the largest second harmonic signal. The results are discussed in the context of ferroelectric phase assemblage in the hafnium zirconium oxide films and demonstrate a path toward a silicon-compatible integrated nonlinear optical material. [ABSTRACT FROM AUTHOR]

Ferroelectric phase stability in hafnium oxide is reported to be influenced by factors that include composition, biaxial stress, crystallite size, and oxygen vacancies. In the present work, the ferroelectric performance of atomic layer deposited Hf0.5Zr0.5O2 (HZO) prepared between TaN electrodes that are processed under conditions to induce variable biaxial stresses is evaluated. The post‐processing stress states of the HZO films reveal no dependence on the as‐deposited stress of the adjacent TaN electrodes. All HZO films maintain tensile biaxial stress following processing, the magnitude of which is not observed to strongly influence the polarization response. Subsequent composition measurements of stress‐varied TaN electrodes reveal changes in stoichiometry related to the different preparation conditions. HZO films in contact with Ta‐rich TaN electrodes exhibit higher remanent polarizations and increased ferroelectric phase fractions compared to those in contact with N‐rich TaN electrodes. HZO films in contact with Ta‐rich TaN electrodes also have higher oxygen vacancy concentrations, indicating that a chemical interaction between the TaN and HZO layers ultimately impacts the ferroelectric orthorhombic phase stability and polarization performance. The results of this work demonstrate a necessity to carefully consider the role of electrode processing and chemistry on performance of ferroelectric hafnia films. [ABSTRACT FROM AUTHOR]

Instead, the elastic moduli may be calculated as[[5]] HT ht (1) HT ht (2) where HT ht is an axial normal component of the elastic stiffness tensor. Furthermore, as shown in Table I, the tensile biaxial stress magnitudes resultant from processing, calculated from sin SP 2 sp HT ht analyses of area detector diffraction patterns, are also lower than reported from the manuscript due to the corrected moduli calculation. 4 from the manuscript is provided in this Erratum, which reflects the stress calculations with the correctly calculated elastic moduli. [Extracted from the article]

We report on the thermal resistances of thin films (20 nm) of hafnium zirconium oxide (Hf1–xZrxO2) with compositions ranging from 0 ≤ x ≤ 1. Measurements were made via time-domain thermoreflectance and analyzed to determine the effective thermal resistance of the films in addition to their associated thermal boundary resistances. We find effective thermal resistances ranging from 28.79 to 24.72 m2 K GW−1 for amorphous films, which decreased to 15.81 m2 K GW−1 upon crystallization. Furthermore, we analyze the heat capacity for two compositions, x = 0.5 and x = 0.7, of Hf1–xZrxO2 and find them to be 2.18 ± 0.56 and 2.64 ± 0.53 MJ m−3 K−1, respectively. [ABSTRACT FROM AUTHOR]