A5054135802- Semiconductor materials and devices
- Advancements in Semiconductor Devices and Circuit Design
- Integrated Circuits and Semiconductor Failure Analysis
- Ferroelectric and Negative Capacitance Devices
- Advanced Memory and Neural Computing
- Terahertz technology and applications
- Semiconductor Quantum Structures and Devices
- Electronic and Structural Properties of Oxides
- GaN-based semiconductor devices and materials
- Semiconductor materials and interfaces
- Superconducting and THz Device Technology
- 3D IC and TSV technologies
- Spectroscopy and Laser Applications
- Silicon Carbide Semiconductor Technologies
- Silicon and Solar Cell Technologies
- Electronic Packaging and Soldering Technologies
- Nanowire Synthesis and Applications
- Thin-Film Transistor Technologies
- Copper Interconnects and Reliability
- Plasmonic and Surface Plasmon Research
- Quantum and electron transport phenomena
- Transition Metal Oxide Nanomaterials
- Carbon Nanotubes in Composites
- Photonic and Optical Devices
- Graphene research and applications
HRL Laboratories (United States)
2024
The Aerospace Corporation
2018-2022
National Institute of Standards and Technology
2017-2022
National Institute of Standards
2022
Physical Measurement Laboratory
2017-2018
NIST Center for Neutron Research
2018
Rensselaer Polytechnic Institute
2004-2010
Institute for Physics of Microstructures
1999
We present experimental results on the optical absorption spectra of epitaxial graphene from visible to terahertz frequency range. In range, is dominated by intraband processes with a dependence similar Drude model. near-IR due interband and measured conductivity close theoretical value e2/4ℏ. extract values for carrier densities, number carbon atom layers, scattering times measurements.
By combining electrical, physical, and transport/atomistic modeling results, this study identifies critical conductive filament (CF) features controlling TiN/HfO2/TiN resistive memory (RRAM) operations. The leakage current through the dielectric is found to be supported by oxygen vacancies, which tend segregate at hafnia grain boundaries. We simulate evolution of a path during forming operation employing multiphonon trap-assisted tunneling (TAT) electron transport model. process analyzed...
Abstract The ability to scale two-dimensional (2D) material thickness down a single monolayer presents promising opportunity realize high-speed energy-efficient memristors. Here, we report an ultra-fast memristor fabricated using atomically thin sheets of 2D hexagonal Boron Nitride, exhibiting the shortest observed switching speed (120 ps) among memristors and low energy (2pJ). Furthermore, study dynamics these ultra-short (120ps-3ns) voltage pulses, frequency range that is highly relevant...
We present theoretical and experimental studies of the direct current effect on detection subterahertz terahertz radiation in gated two-dimensional structures. developed a theory current-driven both for resonant case, when fundamental frequency plasma oscillation is large compared to inverse scattering time, ${\ensuremath{\omega}}_{0}\ensuremath{\tau}⪢1$, nonresonant ${\ensuremath{\omega}}_{0}\ensuremath{\tau}⪡1$, oscillations are damped. predict that, even very small dc would increase...
Strong plasmon resonances have been observed in the terahertz transmission spectra (1–5 THz) of large-area slit-grating-gate AlGaN/GaN-based high-electron-mobility transistor (HEMT) structures at temperatures from 10 to 170 K. The resonance frequencies correspond excitation plasmons with wave vectors equal reciprocal lattice metal grating, which serves both as a gate electrode for HEMT and coupler between incident radiation. Wide tunability by applied voltage demonstrates potential these...
We report on room-temperature, resonant detection of 0.6THz radiation by 250nm gate length GaAs∕AlGaAs heterostructure field-effect transistor. show that the is strongly increased (and becomes resonant) when drain current increases and transistor driven into saturation region. interpret results as due to plasma wave enhanced increasing electron drift velocity.
The random telegraph noise (RTN) related read instability in resistive access memory (RRAM) is evaluated by employing the RTN peak-to-peak (P-p) amplitude as a figure of merit (FoM). Variation FoM value over multiple set/reset cycles found to follow log-normal distribution. P-p decreases with reduction current, which allows scaling RRAM operating current. effect attributed mechanism activation/deactivation electron traps (in HRS) or near LRS) filament that affects current through device.
Detection of subterahertz and terahertz radiation by high electron mobility GaN/AlGaN transistors in the 0.2–2.5 THz frequency range (much higher than cutoff transistors) is reported. Experiments were performed temperature 4–300 K. For lowest temperatures, a resonant response was observed. The resonances interpreted as plasma wave excitations gated two-dimensional gas. Non-resonant detection observed at temperatures above 100 Estimates for noise equivalent power show that these can be used...
We report on the room-temperature, resonant detection of femtosecond pulsed terahertz radiation obtained by optical rectification in a ZnTe crystal. The was realized using 250nm gate length GaAs∕AlGaAs heterostructure field-effect transistor. show that physical mechanism is related to plasma waves excited transistor channel. strongly enhanced increasing drain current and driving into wave instability region. Our results clearly nanometer transistors can be efficient fast detectors for...
We observe a trend between initial leakage currents in polycrystalline HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> resisitive random access memory (RRAM) cells (before forming) and the forming voltages. This points to dominant role played by conduction paths located at grain boundaries, which is promoted oxygen deficiency . One of these then converted into conductive filament responsible for nonvolatile resistance switching. In...
The proposed constant voltage forming (CVF) is shown to increase the resistances of low resistance and high states while reducing their variability. By forcing in all devices occur at same predefined voltage, CVF method eliminates a major cause device-to-device variation associated with randomness values. Moreover, both experiments simulations show that lower voltages suppresses parasitic overshoot current, resulting more controlled smaller filament cross-section operation currents.
We introduce a figure of merit (FoM) to quantify RRAM read current instability, complex multi-level RTN-like signal, generally observed in current. Log(FoM) follows normal statistical distribution describing the probability occurrence fluctuation given amplitude. demonstrate that peak-to-peak RTN amplitude decreases with reduction enables scaling down operating currents. The developed model for instability allows estimate maximum size and minimum reliable operations high density array.
Far infrared spectra of 14 commonly used explosive samples have been measured by using Fourier Transform Infrared Spectroscopy (FTIR) and THz Time-Domain (THz TDS). New absorption resonances between 20 cm<sup>-1</sup> 650 are reported. Below cm<sup>-1</sup>, no clear observed in all the explosives. There is a good consistency far-IR spectrum Far-FTIR TDS explosives 3,5-DNA 2,4-DNT. Observed TNT compared with previously reported theoretical calculation.
Results of room temperature measurement nonresonant sub-terahertz detection by nanoscale silicon MOSFETs under a variety load conditions are reported. The effect device loading is incorporated into existing response models to explain diminished in the sub-threshold region, and calculation noise equivalent power indicates minima near threshold voltage.
We report on enhanced room-temperature detection of terahertz radiation by several connected field-effect transistors. For this nonresonant detection, we have designed, fabricated, and tested plasmonic structures consisting multiple InGaAs/GaAs pseudomorphic high electron-mobility transistors in series. Results show a 1.63-THz response that is directly proportional to the number detecting biased direct drain current at same gate-to-source bias voltages. The responsivity saturation regime was...
Instability of InGaAs channel nMOSFETs with the 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> / ZrO gate stack under positive bias stress demonstrates recoverable and unrecoverable components, which can be tentatively assigned to pre-existing generated defects, respectively. The component is determined primarily associated defects in interfacial layer (IL), slow trapping at...
We report on terahertz detection (from 0.2 THz to 2.4 THz) by Si FinFETs of different widths (with 2, 20, and 200 fins connected in parallel). a small number with feature sizes as short 20 nm 40 nm) showed very high responsivity (far above that previously measured for standard CMOS). explain this improvement negligible narrow channel effects.
The detection of subterahertz (200 GHz) radiation by silicon-on-insulator MOSFETs with submicron gate lengths in the temperature range from ∼8 to 350 K is reported. photoresponse measured against voltage exhibited a maximum near threshold amplitude decreasing temperature. reached at bias close and increased an increase drain-to-source current. This behaviour agrees mechanism linking excitation overdamped plasma waves transistor channel. observed effect could be used for non-destructive,...
The difference in the terahertz response of Si MOSFETs with identical above threshold characteristics but different values leakage current below regime is demonstrated. results show that test can be used as a complementary testing technique MOS VLSI under bias.
We propose a physical model for the fast component ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="TeX">$<1$ </tex-math></inline-formula> s) of positive bias temperature instability (PBTI) process in SiO <sub xmlns:xlink="http://www.w3.org/1999/xlink"><i>x</i></sub> /HfO xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> gate-stacks. The is based on electron-phonon interaction governing trapping/emission...
The accuracy of the split- <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CV</i> mobility extraction method is analyzed in buried-channel InGaAs MOSFETs with a Al <sub xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> gate dielectric and an InP barrier, through "simulated experiment" procedure using 2-D numerical device simulations that are preliminarily calibrated against experimental...
There is an increasing number of reports on polar polymer-based Ferroelectric Field Effect Transistors (FeFETs), where the hysteresis drain current - gate voltage (Id-Vg) curve investigated as result ferroelectric polarization effect. However, separating effect from many factors (such charge injection/trapping and presence mobile ions in polymer) that confound interpretation still confusing controversial. This work presents a methodology to reliably identify confounding which obscure FeFETs....