A5082183465- Semiconductor materials and devices
- Semiconductor materials and interfaces
- Advanced Memory and Neural Computing
- Ferroelectric and Negative Capacitance Devices
- Silicon and Solar Cell Technologies
- Advancements in Semiconductor Devices and Circuit Design
- Electronic and Structural Properties of Oxides
- Integrated Circuits and Semiconductor Failure Analysis
- Ferroelectric and Piezoelectric Materials
- Transition Metal Oxide Nanomaterials
- Copper Interconnects and Reliability
- Silicon Nanostructures and Photoluminescence
- Gas Sensing Nanomaterials and Sensors
- Intermetallics and Advanced Alloy Properties
- Additive Manufacturing Materials and Processes
- Catalytic Processes in Materials Science
- Physics of Superconductivity and Magnetism
- Ga2O3 and related materials
- Molecular Junctions and Nanostructures
- MXene and MAX Phase Materials
- ZnO doping and properties
- Solidification and crystal growth phenomena
- Microwave Dielectric Ceramics Synthesis
- Magnetic properties of thin films
- Nuclear physics research studies
KU Leuven
2007-2021
Samsung (United States)
2015-2020
Samsung (South Korea)
2019
Advanced Liquid Logic
2018
IMEC
2006-2016
Austral University of Chile
2016
Technion – Israel Institute of Technology
2016
University College London
2016
Imec the Netherlands
2009
Applied Materials (United States)
2009
We report on world's smallest HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -based Resistive RAM (RRAM) cell to date, featuring a novel Hf/HfO xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> resistive element stack, with an area of less than 10×10 nm <sup xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , fast ns-range on/off switching times at low-voltages and energy per bit <;0.1pJ. With excellent endurance more 5.10...
By tuning the SET/RESET pulse amplitude conditions, endurance of our 40-nm HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> /Hf 1T1R resistive-random-access-memory devices demonstrates varying failure behaviors after 10 <sup xmlns:xlink="http://www.w3.org/1999/xlink">6</sup> cycles. For unbalanced both low-resistance state (LRS) and high-resistance (HRS) failures may occur, while pulsewidths influences LRS/HRS window stability states....
We demonstrate an SoC logic compatible ferroelectric-metal field effect transistor (FeMFET) digital 2-bit weight cell by monolithic BEOL integration of a ferroelectric (FE) capacitor with the gate conventional Si HK/MG MOSFET. Through optimization area ratio between FE and MOSFET, we show: 1) program/erase write voltages can be scaled down to level, ±1.8 V, simplifying circuitry; 2) speed 100ns; 3) endurance cycles without degradation due elimination charge trapping in FE; 4) 2 bits/cell...
In this letter, we explore the influence of CuxTe1-x layer composition (0.2 &lt; x 0.8) on resistive switching CuxTe1−x/Al2O3/Si cells. While &gt; 0.7 leads to large reset power, similar pure-Cu electrodes, 0.3 results in volatile forming properties. The intermediate range 0.5 shows optimum memory properties, featuring improved control filament programming using &lt;5 μA as well state stability at 85 °C. composition-dependent and are closely associated with phases CuxTe1−x...
Thin films of vanadium dioxide (VO2) have been grown by a low temperature atomic layer deposition process at 150 °C using tetrakis[ethylmethylamino]vanadium as source and ozone reactant gas. Films deposited on SiO2 were amorphous, but during thermal treatment 450 tetragonal VO2(R) was formed. During in situ x-ray diffraction measurements, the semiconductor–metal transition observed reversible between VO2(M1) near 67 °C. Correlated with this phase change, change resistivity more than two...
A detailed kinetic study of the C49 to C54 phase transformation in TiSi2 thin films was performed, obtain full time, temperature, and linewidth dependence fraction transformed during rapid thermal annealing on patterned deep-sub-micron lines. Johnson–Mehl–Avrami analysis showed Avrami exponents 0.8±0.2 for all submicron lines 1.9±0.2 a 40 μm side square structure. The activation energy 3.9 eV independent linewidth. Transformation times increased dramatically as decreased. model based density...
An analytic dynamic hour glass model for HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> RRAM is demonstrated, describing the reset as a equilibrium process and set constriction growth limited by ion mobility current compliance. The dependence on time, voltage forming conditions in good agreement with experiments. Since fully analytical, it can be implemented circuit simulator.
In this work, we present a detailed electrical characterization of TiN\HfO2\Hf\TiN RRAM elements, and show for the first time intrinsic switching characteristics in low current operation regime (100uA till few uA's) small scaled cells (20nm) under DC fast ramps (up to 1MV/s) condition, using newly proposed 2R test structure. The main characteristic parameters SET RESET are defined their speed dependence is characterized. Resistance decrease during observed occur at constant voltage Vtrans,...
We demonstrate sub-500nA switching and tunable set voltage by inserting thin Al <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> layer in TiN\HfO \Hf\TiN RRAM cell. Stack engineering clearly led to novel insights into the phenomenology: (i) O-scavenging is key forming process stack-asymmetry management; (ii) dielectric-stack thinning allows lower current; (iii) `natural'...
A Monte Carlo simulator is developed to investigate the low resistance state (LRS) retention of HfOx based resistive switching memory. The tracks evolution oxygen ions and vacancies by choosing occurrence generation/recombination/migration processes on their corresponding probability at each simulation step. current through resulting conductive filament (CF) configuration then calculated a trap-assisted-tunneling solver. results are corroborated with experimental data. LRS found be CF size...
Two-terminal thin film VO2 devices show an abrupt decrease of resistance when the current or voltage applied exceeds a threshold value. This phenomenon is often described as field-induced metal-insulator transition. We fabricate nano-scale with different electrode separations down to 100 nm and study how dc switching depend on device size temperature. Our observations are consistent Joule heating mechanism governing switching. Pulsed measurements time high state order one hundred...
Analysis of photodepopulation electron traps in HfO2 films grown by atomic layer deposition is shown to provide the trap energy distribution across entire oxide bandgap. The presence revealed two kinds deep energetically distributed at around Et ≈ 2.0 eV and 3.0 below conduction band. Comparison trapped distributions layers prepared using different precursors or subjected thermal treatment suggests that these centers are intrinsic origin. However, common assumption would implicate O...
We report on measurements and modeling of FE HfZrO/SiO2 Ferroelectric-Dielectric (FE-DE) FETs which indicate that many the phenomena attributed to Negative Capacitance can be explained by a delayed response ferroelectric domain switching - referred as Transient (TNC). No traversal stabilized negative capacitance branch is required. Modeling used correlate hysteretic properties material measured transient subthreshold slope (SS) behavior. It found steep SS understood phenomenon, present when...
This paper demonstrates the switching of several conductive filaments in RRAM using a small-size FUSI gate NMOS transistor. The theory for predicting maximum applicable V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">set</sub> is elaborated. Modeling filament conduction with quantum mechanical model reveals that reset operation corresponds to narrowing filament.
Strontium titanate (STO) is a promising candidate as high- dielectric for dynamic random access memory application. STO thin films are deposited by atomic layer deposition using , and precursors. Growth saturation behavior of binary oxides evaluated ellipsometry thickness measurements. The precursor pulse ratio controls the amount Sr Ti incorporated in films. Stoichiometric characterized lowest crystallization temperature largest refractive index, density, constant. An excess or results an...
In this work, the physical and electrical properties of SrxTi1−xOy (STO)-based metal-insulator-metal capacitors (MIMcaps) with various compositions are studied in detail. While most recent studies on STO were done noblelike metal electrodes (Ru, Pt), work focuses a low temperature (250 °C) atomic layer deposition (ALD) process, using an alternative precursor set carefully optimized processing conditions, enabling use low-cost, manufacturable-friendly TiN electrodes. Physical analyses show...
Experiments on internal photoemission of electrons from Si and TiNx into thin Al2O3 layers suggest that crystallization amorphous to the cubic γ-Al2O3 is accompanied by only a ≈ 0.5 eV upshift conduction band bottom edge. As it known in transforming γ-phase, bandgap increases 6.2 8.7 eV, more than 80% this gap widening must occur at VB side gap. The latter suggests interaction between electron states O anions plays dominant role oxide widening.
In this letter, CMOS-compatible Ni/HfO2/TiN resistive random access memory stacks demonstrated attractive unipolar switching properties, showing &gt;103 endurance and long retention at 150 °C. The Ni bottom electrode (BE) improved the yield over NiSiPt BE. To better understand forming mechanism, ab initio simulation time of flight-secondary ion mass spectroscopy were utilized. Compared to BE, BE gives larger diffusion in HfO2 lower formation enthalpy Ni2+ species during electrical...
Transition metal compounds showing a metal-insulator transition (MIT) show complex behavior due to strongly correlated electron effects and offer attractive properties for nano-electronics applications, which cannot be obtained with regular semiconductors. MIT based nano-electronics, however, remains unproven, devices are poorly understood. We point out single one of the major hurdles preventing MIT-electronics: obtaining high Off resistance On-Off ratio in an switch. path toward switch...
We investigate the roles of TiN and Pt materials used as electrodes in resistive-switching HfO2 systems. Well-behaved reset operation is observed on condition anode, which together with strong effect thin insert layers (IL) indicates that switching favored at HfO2\Pt interface. However, properties are hampered by yield reliability issues associated to oxygen runaway forming caused permeability oxygen. TiN\HfO2\(IL)\Pt cells show better due improved buffering. The non-polar, unipolar bipolar...
We report on measurements and modeling of FE HfZrO/SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Ferroelectric-Dielectric (FE-DE) FETs which indicate that phenomena attributed to Negative Capacitance can be explained by a delayed response ferroelectric domain switching. No traversal the stabilized negative capacitance branch is required. Modeling used correlate hysteretic properties material measured transient subthreshold slope...