A5091095889- Magnetic properties of thin films
- Magnetic Properties and Applications
- Characterization and Applications of Magnetic Nanoparticles
- Advanced ceramic materials synthesis
- Semiconductor materials and devices
- Ferroelectric and Negative Capacitance Devices
- Silicon Carbide Semiconductor Technologies
- Physics of Superconductivity and Magnetism
- Advanced Memory and Neural Computing
- Semiconductor materials and interfaces
- ZnO doping and properties
- Metal and Thin Film Mechanics
- Magnetic Properties of Alloys
- Magneto-Optical Properties and Applications
- Microstructure and Mechanical Properties of Steels
- Theoretical and Computational Physics
- Metallic Glasses and Amorphous Alloys
- Multiferroics and related materials
- Electron and X-Ray Spectroscopy Techniques
- Acoustic Wave Resonator Technologies
- Advanced Thermodynamic Systems and Engines
- Architecture and Computational Design
- Superconducting Materials and Applications
- Heusler alloys: electronic and magnetic properties
- Copper Interconnects and Reliability
IMEC
2018-2024
Imec the Netherlands
2024
University of York
2012-2020
St Bartholomew's Hospital
2014
Arizona State University
1998-2008
Orbital ATK (United States)
2002
University of Edinburgh
1988
East–West Center
1984
Oak Ridge National Laboratory
1972
We propose a field-free switching SOT-MRAM concept that is integration friendly and allows for separate optimization of the field component SOT/MTJ stack properties. demonstrate it on 300 mm wafer, using CMOS-compatible processes, we show device performances are similar to our standard SOT-MTJ cells: reliable sub-ns with low writing power across 300mm wafer. Our concept/design opens new area MRAM (SOT, STT VCMA) technology development.
To address the large energy dissipation of our current computing architecture, nonvolatile voltage-gate-assisted spin-orbit-torque (VGSOT) MRAM combines advantages (SOT) and voltage control magnetic anisotropy (VCMA) systems. Here authors study VGSOT writing with perpendicular tunnel junctions, show it to be reliable, low error rate resilience intensive stresses. The spin Hall angle VCMA coefficient allow 30-nm junctions. A multipillar design is suggested, high density close 2-terminal...
We propose a field-free switching SOT-MRAM concept that is integration friendly and allows for separate optimization of the field component SOT/MTJ stack properties. demonstrate it on 300 mm wafer, using CMOS-compatible processes, we show device performances are similar to our standard SOT-MTJ cells: reliable sub-ns with low writing power across 300mm wafer. Our concept/design opens new area MRAM (SOT, STT VCMA) technology development.
Exploring the third dimension in magnonic systems is essential for investigation of alternative physical phenomena and control spin-wave propagation at nanoscale. Here, characteristics spin waves vertical meander-shaped ${\mathrm{Co}}_{40}{\mathrm{Fe}}_{40}{\mathrm{B}}_{20}$ thin films consisting nanosegments located 90\ifmmode^\circ\else\textdegree\fi{} angles with respect to each other are investigated by Brillouin-light-scattering spectroscopy over four Brillouin zones reciprocal space....
We present a detailed study of the impact damage minimizing patterning schemes on electrical performance perpendicular STT-MRAM devices at array level, compatible with 22 nm CMOS technology node. By employing novel scheme involving physical ion beam etch (IBE), etchback and oxidation steps, we show reduction in switching voltage (32%), energy (20%) an improvement reliability window (20%), as compared to conventional etch. These improvements are reported conjunction 10-year data retention...
Abstract Magnetic random access memory (MRAM) is a leading emergent technology that poised to replace current non-volatile technologies such as eFlash. However, controlling and improving distributions of device properties becomes key enabler new applications at this stage development. Here, we introduce non-contact metrology technique deploying scanning NV magnetometry (SNVM) investigate MRAM performance the individual bit level. We demonstrate magnetic reversal characterization in...
We propose a deterministic VCMA writing concept that allows exclusion of the pre-read which is required in conventional write scheme. apply it on 400°C compatible pMTJ devices with high TMR 246% and retention = 54 demonstrate genuine ns-scale speed. Furthermore, we realize reliable 1.1 GHz external field-free switching 20fJ energy by integrating magnetic hard mask as in-plane field generator. An endurance more than 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML"...
For the first time in voltage control of magnetic anisotropy random-access memory (VCMA-MRAM), a large coefficient ≥ 100 fJ/Vm has been demonstrated fully integrated, BEOL compatible, tunnel junctions (MTJ). This was achieved while maintaining high TMR (180%) and thermal stability factor ( <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\Delta > 40$</tex> ). VCMA-induced switching is also explored, showing benefits for low power ultrafast...
We study the offset fields affecting free layer of perpendicularly magnetized tunnel junctions. In extended films, field results from interlayer exchange coupling with reference through MgO oxide. The is thus accompanied a shift and ferromagnetic resonance frequencies. shifts depend on mutual orientation two magnetizations. decreases resistance area product Patterning junction into an STT-MRAM disk-shaped cell changes substantially field, as reduction lateral dimension comes generation stray...
The potentials of integrating thin-film photovoltaic technology into buildings make it the recommended renewable energy source not only for traditional architectures, but also most innovative applications that favour envelopes characterized by free morphologies such as membrane structures. integration Photovoltaic structures offers a promising significant step in market development. However, some challenges and questions are arising relating to applicability systems how they significantly...
In this work, the effect of exchange bias on hysteresis loop CoFe is observed. The evolution coercivities and shift during annealing process has been measured for films deposited NiCr Cu seed layers. Through comparison as field annealed loops, it clear that an biased material, two are due to different reversal processes. This behaviour attributed spin clusters at ferromagnet/antiferromagnet interface, which behave in a similar manner fine particle system.
We report on the effect of 0-5 monoatomic layers Mn deposited at interface a CoFe/IrMn polycrystalline thin film. All samples were produced via sputtering. Thermal activation measurements carried out using well-established York Protocols. In conjunction with grain size analysis performed each sample value antiferromagnet (AF) anisotropy <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">K</i> <sub xmlns:xlink="http://www.w3.org/1999/xlink">AF</sub>...
In this paper, we report our new optical method for the measurement of bandgaps half-metallic ferromagnets (HMFs) that are sensitive to both surface/interface and bulk regions these depending on light incident angles resulting penetration depth. We measured bandgap polycrystalline Co <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> FeSi Heusler alloy thin films at room temperature (RT) as an example. The were deposited MgO(001) Si/SiO...
For the first time, we demonstrate, using an atomistic description of a 30nm diameter spin-transfer-torque magnetic random access memories (STT-MRAM), that difference in mechanical properties its sub-nanometer layers induces high compressive strain tunnel junction (MTJ) and leads to detrimental magnetostrictive effect. Our model explains issues met engineering electrical performances scaled STT-MRAM devices. The resulting built stack, particularly MgO barrier (t-MgO), associated non-uniform...
Voltage control of the magnetic anisotropy (VCMA) effect enables a voltage-mediated magnetization switching mechanism for lower-power applications. In this work, we experimentally investigate characteristics VCMA-induced and observe clear decrease in critical voltage (Vc) at elevated temperatures. A 50% reduction Vc is quantified when increasing ambient temperature (T) from 300 K to 360 K. Such T-dependence well explained with variations saturation (MS), interfacial (Ki), VCMA coefficient...
The CoFeB/MgO/CoFeB magnetic tunnel junction (MTJ) is the central element of any high performance perpendicular Magnetoresistive Random Access Memory (MRAM) device. MgO barrier, in contact with CoFeB films at both sides junction, provides a magneto resistance (TMR) and anisotropy (PMA) thanks to crystalline quality MgO/CoFeB interface achieved upon post-deposition annealing. We study MgGa2O4 as an alternative barrier material due its lower bandgap show how introduce it into state-of-the-art...
The effect of sub-500 nm patterning on exchange bias in thin films has been studied. Experimental results are compared to the York model which modified take into account grain cutting at edges structures. Exchange (Hex) was found decrease with element size. form variation Hex size matches that experiment. Numerical agreement not achieved for Hex. However, predictions median blocking temperature ⟨TB⟩ agree disagreement is attributed edge roughness structures will affect quality interface...
Due to the advent of antiferromagnetic (AF) spintronics there is a burgeoning interest in AF materials for wide range potential and actual applications. Generally, AFs are characterized via ordering at Neel temperature (TN) but, have stable configuration, it necessary that material sufficient level anisotropy so as maintain orientation given magnetic state fixed one direction. Unlike case ferromagnets little established data on particular its origins those factors which control it. In this...
In this study, a newly developed band-gap measurement technique has been used to characterise epitaxial Co2FeAl0.5Si0.5 (CFAS) films. The CFAS films were deposited on MgO(001) substrate by ultra high vacuum molecular beam epitaxy. for the as was found be ∼110 meV when measured at room temperature. This simple provides macroscopic analysis of half-metallic properties thin film. allows optimisation growth and annealing conditions.
Measuring thermal stability in magnetic random access memory devices is non-trivial. Recently, there has been much discussion on the appropriate model to use: single domain or wall nucleation. Of particular challenge assessing maximum size at which can be assumed. Typically, this estimated range of 20–30 nm based a value exchange stiffness (Aex) that assumed, using indirect measurements derived from significantly thicker films. In work, it proposed measured directly via “activation volume”...
One of the key challenges in industrialisation Voltage Controlled Magnetic Anisotropy-Magnetic Random Access Memory (VCMA-MRAM) is reliability writing process. As VCMA a non-deterministic write process, it more sensitive to any offset Free Layer (FL) ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\mu _{0}H_{off}$</tex-math></inline-formula> ) due stray fields generated by Hard (HL)/Reference (RL), as...