Search

Cap layers have been used to modulate the effective work function (EWF) for high-k/metal-gate CMOS devices. We have investigated the impact of stacking cap layers on the EWF. Stacked cap layers consisting of two sequential cap layers, including Al2O3, Dy2O3, Sc2O3, and La2O3, were formed on HfSiON or SiON as host dielectrics. It is demonstrated that the EWF change due to the stacked cap layers corresponds to the sum of the EWF change from each single cap layer. Furthermore, no host dielectric dependence on the shifts is observed. This behavior is attributed to the complete intermixing of the stacked cap layers with the host dielectrics. [ABSTRACT FROM AUTHOR]

In this study, we report on the characterization of the magnetoelectric coupling coefficient in Ba-substituted Pb(Zr, Ti)O3/Co40Fe40B20 (BPZT/CoFeB) nanoscaled waveguides with lateral dimensions of 700 nm using propagating spin-wave spectroscopy. The characterization was conducted in a Damon–Eshbach configuration to maximize the magnetoelastic coupling strength, as predicted by strain distribution calculations using finite element simulations. The spin-wave resonance frequency is controlled by applying bias voltages on the magnetoelectric waveguide. The magnitude of the frequency shift was correlated with the strength of the magnetoelastic field, which reached a maximum value of 5.71 mT in our experiments. In addition, the results demonstrated that the coupling coefficient behavior is associated with the hysteretic ferroelectric nature of BPZT, reaching a maximum value of 1.69 mT/V. [ABSTRACT FROM AUTHOR]

By their very nature, spin waves (SWs) with different frequencies can propagate through the same waveguide, while mostly interfering with their own species. Therefore, more SW encoded data sets can coexist, propagate, and interact in parallel, which opens the road toward hardware replication-free parallel data processing. In this article, we take advantage of these features and propose a novel data parallel SW-based computing approach. To explain and validate the proposed concept, byte-wide 2-input XOR and 3-input majority gates are implemented and validated by means of Object-Oriented MicroMagnetic Framework (OOMMF) simulations. Furthermore, we introduce an optimization algorithm meant to minimize the area overhead associated with multifrequency operation and demonstrate that it diminishes the byte-wide gate area by 30% and 41% for XOR and majority implementations, respectively. To get inside on the practical implications of our proposal, we compare the byte-wide gates with conventional functionally equivalent scalar SW gate-based implementations in terms of area, delay, and power consumption. Our results indicate that the area optimized 8-bit 2-input XOR and 3-input majority gates require 4.47x and 4.16x less area, respectively, at the expense of 5% and 7% delay increase, respectively, without inducing any power consumption overhead. Finally, we discuss factors that are limiting the currently achievable parallelism to 8 for phase-based gate output detection and demonstrate by means of OOMMF simulations that this can be increased 16 for threshold-based detection-based gates. [ABSTRACT FROM AUTHOR]

This special edition contains the proceedings of ALTECH 2014 - Analytical Techniques for Precise Characterisation of Nanomaterials, Symposium H of the European Materials Research Society (E-MRS) Spring Meeting 2014 that was held in Lille, France, from 26th-30th May. ALTECH is a series of conferences initiated in 1989. The conference was offered as a satellite of symposium of semiconductor conferences in Europe or, on occasion, in the U.S., with a strong focus on analytical techniques for microelectronics manufacturing and research. In 2012, the German metrology institute PTB joined the executive board of the ALTECH and proposing a broadening of the ALTECH scope towards the characterization of nanomaterials. While imec has ensured the organizational continuity, further European metrology institutes adhered to the organizational board which made ALTECH to an important European metrology event on nanomaterials characterisation. Our conference covered recent and innovative developments in analytical techniques that can provide precise characterization of surfaces and materials, characterization of nanostructures and study of thin films with nanoscale and/or atomic resolution. In total, 167 contributions were presented, including 11 invited presentations, 87 contributed oral presentations and 69 poster presentations. The event also included significant contributions from the European Metrology Research Program projects 'Metrology for the manufacturing of thin films', 'Traceable characterization of nanostructured devices', 'Novel electronic devices based on control of strain at the nanoscale', and 'Chemical metrology tools for manufacture of advanced biomaterials in the medical device industry' including related tutorial sessions. Nanomaterials have unique properties associated with their small dimensionality. Functional nanomaterials are rapidly finding wider use in modern technological products in many areas, for example, displays, energy conversion, energy storage, sensors and biosensors. The accurate characterization of nanoscale materials is essential for the development of such innovative products. Conversely, properly engineered nanomaterials are currently seen as one of the most promising tools for high resolution optical microscopy. The objective of ALTECH was to highlight metrology capabilities for both the determination of the key structural and material property parameters in view of a better understanding of the related functional properties. One major focus was the application of these techniques to new and complex material systems with high potential of industrial impact, including nanoscale objects (nanowires, quantum dots), nanostructured thin films of organic, hybrid, or inorganic semiconductors, and functionalized surfaces. A special focus was given to complementary metrology in terms of using different analytical techniques with the aim of ensuring accuracy and traceability, i.e. the inclusion of a well-described uncertainty budget. As many of these techniques depend on modelling to achieve reliable results, effective material analysis and computational analysis of materials and thin layers were also a key topic. These proceedings contain a selection of 23 manuscripts published in pss (a) and pss (c). pss (c) is organized in three sections: - Analysis of surfaces and materials - Characterization of nanostructures - Study of thin films. We would like to thank all invited speakers, contributors and attendees for their high-quality contributions and excellent discussions which made ALTECH a very successful meeting. We are grateful to the scientific committee and external colleagues who supported the symposium and the organisation of these proceedings as well as acted as session chairs and reviewers. We thank the E-MRS headquarter staff for their assistance in organising the symposium as well as Wiley-VCH for helping with the publication of these proceedings. We also would like to acknowledge the sponsorship of several companies and institutions (NPL, Berlin Partner, Rigaku, Elexience, EXSA, INRIM, AXO Dresden, Sentech), as well as the support of the European Union through the European Metrology Research Programme (EMRP), projects IND07 ThinFilms and NEW01 TReND, IND54 Nanostrain, and IND56 Q-AIMDS. The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union. Andreas Nutsch, PTB, Germany Fernando Araujo de Castro, NPL, U.K. Christoph Adelmann, Imec, Belgium Blanka Detlefs, CEA-Leti, France Guest Editors [ABSTRACT FROM AUTHOR]

By its very nature, Spin Wave (SW) interference provides intrinsic support for Majority logic function evaluation. Due to this and the fact that the 3-input Majority (MAJ3) gate and the inverter constitute a universal Boolean logic gate set, different MAJ3 gate implementations have been proposed. However, they cannot be directly utilized for the construction of larger SW logic circuits as they lack a key cascading mechanism, i.e., fanout capability. In this paper, we introduce a novel ladder-shaped SW MAJ3 gate design able to provide a maximum fanout of 2 (FO2). The proper gate functionality is validated by means of micromagnetic simulations, which also demonstrate that the amplitude mismatch between the two outputs is negligible, proving that an FO2 is properly achieved. Additionally, we evaluate the gate area and compare it with SW state-of-the-art and 15 nm CMOS counterparts working under the same conditions. Our results indicate that the proposed structure requires a 12× less area than the 15 nm CMOS MAJ3 gate and that at the gate level, the fanout capability results in 16% area savings, when compared to the state-of-the-art SW majority gate counterparts. [ABSTRACT FROM AUTHOR]

This paper provides a tutorial overview over recent vigorous efforts to develop computing systems based on spin waves instead of charges and voltages. Spin-wave computing can be considered a subfield of spintronics, which uses magnetic excitations for computation and memory applications. The Tutorial combines backgrounds in spin-wave and device physics as well as circuit engineering to create synergies between the physics and electrical engineering communities to advance the field toward practical spin-wave circuits. After an introduction to magnetic interactions and spin-wave physics, the basic aspects of spin-wave computing and individual spin-wave devices are reviewed. The focus is on spin-wave majority gates as they are the most prominently pursued device concept. Subsequently, we discuss the current status and the challenges to combine spin-wave gates and obtain circuits and ultimately computing systems, considering essential aspects such as gate interconnection, logic level restoration, input–output consistency, and fan-out achievement. We argue that spin-wave circuits need to be embedded in conventional complementary metal–oxide–semiconductor (CMOS) circuits to obtain complete functional hybrid computing systems. The state of the art of benchmarking such hybrid spin-wave–CMOS systems is reviewed, and the current challenges to realize such systems are discussed. The benchmark indicates that hybrid spin-wave–CMOS systems promise ultralow-power operation and may ultimately outperform conventional CMOS circuits in terms of the power-delay-area product. Current challenges to achieve this goal include low-power signal restoration in spin-wave circuits as well as efficient spin-wave transducers. [ABSTRACT FROM AUTHOR]

Ultrathin lanthanide (Nd, Pr, Eu, Sm) oxide films with functional dielectric properties down to 3.3 nm thickness were deposited by aqueous chemical solution deposition (CSD) onto hydrophilic SiO2/Si substrates. Precursor solutions were prepared from the oxides via an intermediate, solid Ln(III)citrate. A film heat treatment scheme was derived from thermogravimetric analysis of the precursor gels, showing complete decomposition by 600 °C. Crystalline phase formation in the films depended on the lanthanide, annealing temperature, and citric acid content in the precursor. Through variation of the precursor concentration and number of deposited layers, thickness series of uniform films were obtained down to ~3 nm. The film uniformity was demonstrated both by atomic force microscopy and cross-section transmission electron microscopy. The lanthanide oxide films possessed good dielectric properties. It was concluded that aqueous CSD allows deposition of uniform ultrathin films and may be useful for the evaluation of new high-k candidate materials. [ABSTRACT FROM AUTHOR]

We report on the resonant excitation of spin waves in micro-structured magnetic thin films by short-wavelength surface acoustic waves (SAWs). The spin waves as well as the acoustic waves are studied by micro-focused Brillouin light scattering spectroscopy. At low magnetic bias fields, a resonant phonon–magnon conversion is possible, which results in the excitation of short-wavelength spin waves. Using micromagnetic simulations, we verify that during this excitation both energy and linear momentum are conserved and fully transferred from the SAW to the spin wave. This conversion can already be detected after an interaction length of a few micrometers. Thus, our findings pave the way for miniaturized magneto-elastic spin-wave emitters for magnon computing. [ABSTRACT FROM AUTHOR]

We derive a lumped circuit model for inductive antenna spin-wave transducers in the vicinity of a ferromagnetic medium. The model considers the antenna's Ohmic resistance, its inductance, as well as the additional inductance due to the excitation of ferromagnetic resonance or spin waves in the ferromagnetic medium. As an example, the additional inductance is discussed for a wire antenna on top of a ferromagnetic waveguide, a structure that is characteristic for many magnonic devices and experiments. The model is used to assess the scaling properties and the energy efficiency of inductive antennas. Issues related to scaling antenna transducers to the nanoscale and possible solutions are also addressed. [ABSTRACT FROM AUTHOR]

Highlights: [•] We examine degradation of Ta2O5 high-k oxide. [•] Effect of recrystallization on the electrical properties of Ta2O5 is investigated. [•] Poly-crystalline Ta2O5 shows different conductive domains. [•] Conductive atomic force microscopy (C-AFM) and TEM are used for characterization. [Copyright &y& Elsevier]

Electrical four-terminal sensing at (sub-)micrometer scales enables the characterization of key electromagnetic properties within the semiconductor industry, including materials' resistivity, Hall mobility/carrier density, and magnetoresistance. However, as devices' critical dimensions continue to shrink, significant over/underestimation of properties due to a by-product Joule heating of the probed volume becomes increasingly common. Here, we demonstrate how self-heating effects can be quantified and compensated for via 3ω signals to yield zero-current transfer resistance. Under further assumptions, these signals can be used to characterize selected thermal properties of the probed volume, such as the temperature coefficient of resistance and/or the Seebeck coefficient. [ABSTRACT FROM AUTHOR]

We report on the design, fabrication, and characterization of compact tunable yttrium iron garnet (YIG)-based RF resonators based on μm-sized spin-wave cavities. Inductive antennas with both ladder and meander configurations were used as transducers between spin waves and RF signals. The excitation of ferromagnetic resonance and standing spin waves in the YIG cavities led to sharp resonances with quality factors up to 350. The observed spectra were in excellent agreement with a model based on the spin-wave dispersion relations in YIG, showing a high magnetic field tunability of about 29 MHz/mT. [ABSTRACT FROM AUTHOR]

Spin wave modes in magnetic waveguides with the width down to 320 nm have been studied by electrical propagating spin-wave spectroscopy and micromagnetic simulations for both longitudinal and transverse magnetic bias fields. For longitudinal bias fields, a 1.3 GHz wide spin-wave band was observed in agreement with analytical dispersion relations for uniform magnetization. However, the transverse bias field led to several distinct bands, corresponding to different quantized width modes, with both negative and positive slopes. Micromagnetic simulations showed that, in this geometry, the magnetization was nonuniform and tilted due to the strong shape anisotropy of the waveguides. Simulations of the quantized spin-wave modes in such nonuniformly magnetized waveguides resulted in spin wave dispersion relations in good agreement with the experiments. [ABSTRACT FROM AUTHOR]

Al x Sc 1-x thin films have been studied with compositions around Al 3 Sc (x = 0.75) for potential interconnect metallization applications. As-deposited 25 nm thick films were x-ray amorphous but crystallized at 190 °C, followed by recrystallization at 440 °C. After annealing at 500 °C, 24 nm thick stoichiometric Al 3 Sc showed a resistivity of 12.6 μΩcm, limited by a combination of grain boundary and point defect (disorder) scattering. Together with ab initio calculations that found a mean free path of the charge carriers of 7 nm for stoichiometric Al 3 Sc, these results indicate that Al 3 Sc bears promise for future interconnect metallization schemes. Challenges remain in minimizing the formation of secondary phases as well as in the control of the non-stoichiometric surface oxidation and interfacial reactions with underlying dielectrics. [Display omitted] • Al x Sc 1-x thin films (around x = 0.75) for potential interconnect metallization applications. • Al3Sc showed a resistivity of 12.6 μΩcm at 24 nm thick after 500oC annealing, the lowest observed for thin aluminide intermetallics so far. [ABSTRACT FROM AUTHOR]

The temperature coefficients of the resistivity (TCR) of Cu, Ru, Co, Ir, and W thin films have been investigated as a function of film thickness below 10 nm. Ru, Co, and Ir show bulk-like TCR values that are rather independent of the thickness, whereas the TCR of Cu increases strongly with the decreasing thickness. Thin W films show negative TCR values, which can be linked to high disorder. The results are qualitatively consistent with a temperature-dependent semiclassical thin-film resistivity model that takes into account phonon, surface, and grain boundary scattering. The results indicate that the thin-film resistivity of Ru, Co, and Ir is dominated by grain boundary scattering, whereas that of Cu is strongly influenced by surface scattering. [ABSTRACT FROM AUTHOR]

The emerging field of magnonics uses spin waves and their quanta, magnons, to implement wave‐based computing on the micro‐ and nanoscale. Multifrequency magnon networks would allow for parallel data processing within single logic elements, whereas this is not the case with conventional transistor‐based electronic logic. However, a lack of experimentally proven solutions to efficiently combine and separate magnons of different frequencies has impeded the intensive use of this concept. Herein, the experimental realization of a spin‐wave demultiplexer enabling frequency‐dependent separation of magnonic signals in the gigahertz range is demonstrated. The device is based on 2D magnon transport in the form of spin‐wave beams in unpatterned magnetic films. The intrinsic frequency dependence of the beam direction is exploited to realize a passive functioning obviating an external control and additional power consumption. This approach paves the way to magnonic multiplexing circuits enabling simultaneous information transport and processing. [ABSTRACT FROM AUTHOR]

The microwave dielectric properties of (Ba0.1Pb0.9)(Zr0.52Ti0.48)O3 (BPZT) and ZnO thin films with thicknesses below 2~\mu \textm were investigated. No significant dielectric relaxation was observed for both BPZT and ZnO up to 30 GHz. The intrinsic dielectric constant of BPZT was as high as 980 at 30 GHz. The absence of strong dielectric dispersion and loss peaks in the studied frequency range can be linked to the small grain diameters in these ultrathin films. [ABSTRACT FROM AUTHOR]

We present a new micro Hall effect measurement method using non-equidistant electrodes. We show theoretically and verify experimentally that it is advantageous to use non-equidistant electrodes for samples with low Hall sheet resistance. We demonstrate the new method by experiments where Hall sheet carrier densities and Hall mobilities of Ruthenium thin films (3-30 nm) are determined. The measurements show that it is possible to measure Hall mobilities as low as 1 cm2V−1s−1 with a relative standard deviation of 2-3%. We show a linear relation between measured Hall sheet carrier density and film thickness. Thus, the method can be used to monitor thickness variations of ultra-thin metal films. [ABSTRACT FROM AUTHOR]

Abstract: We report on the synthesis of Cu3Ge films by exposing Cu films to germane (GeH4). The process window was established by investigating the influence of the GeH4 partial pressure, the soak temperature, and the soak time on Cu films of different thickness. It is shown that short exposures of germane led to Cu-rich germanides, while an excessive GeH4 supply resulted in a Cu3Ge/Ge mixed phase. The germanidation reaction was found to be selective and required the prior removal of the native Cu oxide by in situ plasma cleaning. X-ray diffraction and transmission electron microscopy showed that the Cu3Ge films were crystalline as deposited in the orthorhombic phase and were textured. The films were homogenous in composition. Thin films consisted of Cu3Ge islands connected by a thin wetting layer. Fully continuous layers were however found for larger film thicknesses. The continuity of the Cu3Ge film was also found to be influenced by the pseudosubstrate: the films were more continuous on TaN/Ta than on SiO2. The electric properties of the Cu3Ge films on both TaN/Ta and SiO2 pseudosubstrates are presented and compared. [Copyright &y& Elsevier]

We describe an extension of the micromagnetic finite difference simulation software MuMax3 to solve elasto-magneto-dynamical problems. The new module allows for numerical simulations of magnetization and displacement dynamics in magnetostrictive materials and structures, including both direct and inverse magnetostriction. The theoretical background is introduced, and the implementation of the extension is discussed. The magnetoelastic extension of MuMax3 is freely available under the GNU General Public License v3., Competing Interests: No competing interests were disclosed., (Copyright: © 2021 Vanderveken F et al.)

Spin waves are excitations in ferromagnetic media that have been proposed as information carriers in hybrid spintronic devices with much lower operation power than conventional charge-based electronics. Their wave nature can be exploited in majority gates by using interference for computation. However, a scalable spin-wave majority gate that can be cointegrated alongside conventional electronics is still lacking. Here, we demonstrate a submicrometer inline spin-wave majority gate with fan-out. Time-resolved imaging of the magnetization dynamics by scanning transmission x-ray microscopy illustrates the device operation. All-electrical spin-wave spectroscopy further demonstrates majority gates with submicrometer dimensions, reconfigurable input and output ports, and frequency-division multiplexing. Challenges for hybrid spintronic computing systems based on spin-wave majority gates are discussed., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).)

The recent demonstration of ferroelectricity in ultrathin HfO 2 has kickstarted a new wave of research into this material. HfO 2 in the orthorhombic phase can be considered the first and only truly nanoscale ferroelectric material that is compatible with silicon-based nanoelectronics applications. In this article, we demonstrate the ferroelectric control of the magnetic properties of cobalt deposited on ultrathin aluminum-doped, atomic layer deposition-grown HfO 2 ( t HfO 2 = 6.5 nm). The ferroelectric effect is shown to control the shape of the magnetic hysteresis, quantified here by the magnetic switching energy. Furthermore, the magnetic properties such as the remanence are modulated by up to 41%. We show that this modulation does not only correlate with the charge accumulation at the interface but also shows an additional component associated with the ferroelectric polarization switching. An in-depth analysis using first order reversal curves shows that the coercive and interaction field distributions of cobalt can be modulated up to, respectively, 5.8% and 10.5% with the ferroelectric polarization reversal.

In magnetic materials, nontrivial spin textures may emerge due to the competition among different types of magnetic interactions. Among such spin textures, chiral magnetic solitons represent topologically protected spin configurations with particle-like properties. Based on atomistic spin dynamics simulations, we demonstrate that these chiral magnetic solitons are ideal to use for logical operations, and we demonstrate the functionality of a three-input majority gate, in which the input states can be controlled by applying an external electromagnetic field or spin-polarized currents. One of the main advantages of the proposed device is that the input and output signals are encoded in the chirality of solitons, that may be moved, allowing to perform logical operations using only minute electric currents. As an example we illustrate how the three input majority gate can be used to perform logical relations, such as Boolean AND and OR.