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29 results on '"Kühnel, Kati"'

7. Impact of Ferroelectric Layer Thickness on Reliability of Back‐End‐of‐Line‐Compatible Hafnium Zirconium Oxide Films

Author

Sünbül, Ayse, primary, Lehninger, David, additional, Hoffmann, Raik, additional, Olivo, Ricardo, additional, Prabhu, Aditya, additional, Schöne, Fred, additional, Kühnel, Kati, additional, Döllgast, Moritz, additional, Haufe, Nora, additional, Roy, Lisa, additional, Kämpfe, Thomas, additional, Seidel, Konrad, additional, and Eng, Lukas M., additional

Published
2022
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9. Impact of Ferroelectric Layer Thickness on Reliability of Back‐End‐of‐Line‐Compatible Hafnium Zirconium Oxide Films.

Author

Sünbül, Ayse, Lehninger, David, Hoffmann, Raik, Olivo, Ricardo, Prabhu, Aditya, Schöne, Fred, Kühnel, Kati, Döllgast, Moritz, Haufe, Nora, Roy, Lisa, Kämpfe, Thomas, Seidel, Konrad, and Eng, Lukas M.

Subjects
HAFNIUM oxide films, FERROELECTRIC devices, STRAY currents, HAFNIUM oxide, ELECTRIC fields, FERROELECTRIC polymers
Abstract

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]

Published
2023
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11. Tuning Hyrbrid Ferroelectric and Antiferroelectric Stacks for Low Power FeFET and FeRAM Applications by Using Laminated HSO and HZO films

Author

Ali, Tarek, primary, Lehninger, David, additional, Lederer, Maximilian, additional, Li, Songrui, additional, Kühnel, Kati, additional, Mart, Clemens, additional, Mertens, Konstantin, additional, Hoffmann, Raik, additional, Olivo, Ricardo, additional, Emara, Jennifer, additional, Biedermann, Kati, additional, Metzger, Joachim, additional, Binder, Robert, additional, Czernohorsky, Malte, additional, Kämpfe, Thomas, additional, Müller, Johannes, additional, Seidel, Konrad, additional, and Eng, Lukas M., additional

Published
2022
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12. Three-Dimensional Metal-Insulator-Metal Decoupling Capacitors with Optimized ZrO 2 ALD Properties for Improved Electrical and Reliability Parameters.

Author

Falidas, Konstantinos Efstathios, Kühnel, Kati, Rudolph, Matthias, Everding, Maximilian B., Czernohorsky, Malte, and Heitmann, Johannes

Subjects
*DIELECTRIC thin films, *CAPACITORS, *ATOMIC layer deposition, *CURRENT density (Electromagnetism), *DIELECTRIC films, *STRAY currents, *METAL oxide semiconductor capacitors
Abstract

Embedded three-dimensional (3-D) metal-insulator-metal (MIM) decoupling capacitors with high-κ dielectric films of high capacitance and long-life time are increasingly needed on integrated chips. Towards achieving better electrical performance, there is a need for investigation into the influence of the variation in atomic layer deposition (ALD) parameters used for thin high-κ dielectric films (10 nm) made of Al2O3-doped ZrO2. This variation should always be related to the structural uniformity, the electrical characteristics, and the electrical reliability of the capacitors. This paper discusses the influence of different Zr precursor pulse times per ALD cycle and deposition temperatures (283 °C/556 K and 303 °C/576 K) with respect to the capacitance density (C-V), voltage linearity and leakage current density (I-V). Moreover, the dielectric breakdown and TDDB characteristics are evaluated under a wide range of temperatures (223–423 K). [ABSTRACT FROM AUTHOR]

Published
2022
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13. Impact of the Ferroelectric Stack Lamination in Si Doped Hafnium Oxide (HSO) and Hafnium Zirconium Oxide (HZO) Based FeFETs: Toward High-Density Multi-Level Cell and Synaptic Storage

Author

Ali, Tarek, primary, Kühnel, Kati, additional, Olivo, Ricardo, additional, Lehninger, David, additional, Müller, Franz, additional, Lederer, Maximilian, additional, Rudolph, Matthias, additional, Oehler, Sebastian, additional, Mertens, Konstantin, additional, Hoffmann, Raik, additional, Zimmermann, Katrin, additional, Schramm, Philipp, additional, Metzger, Joachim, additional, Binder, Robert, additional, Czernohorsky, Malte, additional, Kämpfe, Thomas, additional, Seidel, Konrad, additional, Müller, Johannes, additional, Van Houdt, Jan, additional, and Eng, Lukas M., additional

Published
2021
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14. A FeFET with a novel MFMFIS gate stack: towards energy-efficient and ultrafast NVMs for neuromorphic computing

Author

Ali, Tarek, primary, Mertens, Konstantin, additional, Kühnel, Kati, additional, Rudolph, Matthias, additional, Oehler, Sebastian, additional, Lehninger, David, additional, Müller, Franz, additional, Revello, Ricardo, additional, Hoffmann, Raik, additional, Zimmermann, Katrin, additional, Kämpfe, Thomas, additional, Czernohorsky, Malte, additional, Seidel, Konrad, additional, Van Houdt, Jan, additional, and Eng, Lukas M, additional

Published
2021
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18. Surface Dependent Performance of Ultrathin TiN Films as an Electrically Conducting Li Diffusion Barrier for Li-Ion Based Devices

Author

Speulmanns, Jan, Kia, Alireza M., Kühnel, Kati, Bönhardt, Sascha, Weinreich, Wenke, and Publica

Abstract

In-depth understanding of lithium (Li) diffusion barriers is a crucial factor for enabling Li-ion based devices like 3D thin-film batteries and synaptic redox transistors integrated on silicon substrates. Diffusion of Li-ions into the silicon can damage surrounding components, detach the device itself, lead to battery capacity loss, and cause uncontrolled change of the transistor channel conductance. In this study, we analyze for the first time ultrathin 10 nm titanium nitride (TiN) films as bifunctional Li-ion diffusion barrier and current collector. Thermal atomic layer deposition (ALD) and pulsed chemical vapor deposition (pCVD) are employed for manufacturing. 10 nm ALD films demonstrate excellent blocking capability with an insertion of only 0.03 Li per TiN formula unit exceeding 200 galvanostatic cycles at 3 µA/cm2 between 0.05 and 3 V vs. Li/Li+. An ultra-low electrical resistivity of 115 µO cm is obtained. In contrast, a partial barrier breakdown is observed for 10 nm pCVD films. High surface quality with low contamination is identified as a key factor for the excellent performance of ALD TiN. Conformal deposition of 10 nm ALD TiN in 3D structures with high aspect ratios of up to 20:1 is demonstrated. The measured capacities of the surface area enhanced samples are in good agreement with the expected values. High-temperature blocking capability is proven for a typical electrode crystallization step. Ultrathin ALD TiN is an ideal candidate as an electrically conducting Li-ion diffusion barrier for Si-integrated devices.

Published
2020

23. Ferroelectric and pyroelectric properties of polycrystalline La-doped HfO2 thin films

Author

Mart, Clemens, Kühnel, Kati, Kämpfe, Thomas, Zybell, Sabine, Weinreich, Wenke, and Publica

Abstract

Lanthanum has been identified as a promising dopant to achieve ferroelectricity in HfO2 thin films in recent theoretical and experimental studies. In this work, the pyroelectric properties of 10 nm thick polycrystalline La-doped HfO2 layers manufactured by thermal atomic layer deposition are assessed employing a sinusoidal temperature profile. Compared to Si doping, La offers a broader dopant range in which ferroelectric behavior is obtained, making the material interesting for large-scale integration and deposition on area-enhanced substrates. Pyroelectric coefficients of up to −80 mC/m2 K are obtained using an optimized stoichiometry, which is comparable to earlier measurements with Si-doped HfO2 samples. Phase-sensitive evaluation of the measured current confirms the pyroelectric origin with minimal spurious contributions. The results are discussed with respect to the ferroelectric switching behavior, which is analyzed employing first-order reversal curve measurements. It is found that there is no simple linear relationship between the remanent polarization and the pyroelectric coefficient. Experimental evidence indicates that the pyroelectric response in polycrystalline thin films is modulated by internal bias fields, which can arise from charged defects. This illustrates the need for careful tuning of the manufacturing conditions and the film phase composition in future applications such as pyroelectric sensors, energy harvesting, or solid-state cooling.

Published
2019

24. High-density energy storage in Si-doped hafnium oxide thin films on area-enhanced substrates

Author

Kühnel, Kati, Czernohorsky, M., Riedel, Steffen, Mart, Clemens, Weinreich, Wenke, and Publica

Abstract

Capacitors based on 10 nm antiferroelectric silicon-doped hafnium oxide (Si:HfO2) thin films are investigated in terms of energy storage efficiency, cycling endurance, and reliability. Atomic layer deposition (ALD) on an area-enhanced substrate with large-scale arrays of deep-trench structures is used to significantly increase the energy density, yielding a value of 450 mJ/cm2 and an energy storage efficiency of 67% at a voltage of 3 V. High breakdown fields are obtained, and the reliability measurement indicates that more than 90% of the devices survive three years when subjected to an operating voltage of 3 V. The film stoichiometry is optimized in terms of energy storage properties to achieve an antiferroelectric-like hysteresis loop with low fatigue during electric field cycling and uniform electrical characteristics throughout the 300 mm wafer. Si:HfO2 is a promising material for novel integrated energy storage applications, as it combines CMOS compatible manufacturing, high scalability, and conformal deposition using ALD.

Published
2019

28. Development of Rutile Titanium Oxide Thin Films as Battery Material Component Using Atomic Layer Deposition.

Author

Kia, Alireza M., Bönhardt, Sascha, Zybell, Sabine, Kühnel, Kati, Haufe, Nora, and Weinreich, Wenke

Subjects
ATOMIC layer deposition, TITANIUM dioxide films, RUTILE, TITANIUM nitride, THIN films, TITANIUM oxides
Abstract

Herein, growth kinetics, crystal structure, and the uniformity of titanium oxide (TiO2) thin films prepared using atomic layer deposition (ALD) and plasma‐enhanced ALD (PE‐ALD) are studied. TiO2 thin films are grown using titanium tetrachloride (TiCl4), water, and oxygen precursors. Using ALD, TiO2 is grown in the temperature range of 270–310 °C thermally and in the range of 300–400 °C with PE‐ALD. In spite of the plasma process yielding better uniformity on planar structures, the optimized thermal process provides a remarkable conformal step coverage within deep trenches. In addition, the change in the crystal structure and phase transitions of TiO2 is presented herein. This is attempted at using TiO2 as a component material to grow lithium titanate (LTO) as an electrode material in solid‐state lithium‐ion batteries (LIBs). Thereby, different substrates are used. In comparison to the silicon (Si) substrate, silicon oxide (SiO2) and titanium nitride (TiN) lead to crystal phase transformation while annealing. Measurements are performed using in situ high‐temperature X‐ray diffraction (HT‐XRD). It is also shown that when TiN is sandwiched between TiO2 and the silicon substrate, the TiO2 thin film (25 nm) gradually changes from an anatase to a rutile structure. [ABSTRACT FROM AUTHOR]

Published
2020
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