A5082674134- Advanced MEMS and NEMS Technologies
- Advanced Surface Polishing Techniques
- Criminal Law and Policy
- Advanced Sensor and Energy Harvesting Materials
- Semiconductor materials and devices
- Shape Memory Alloy Transformations
- Mechanical and Optical Resonators
- Law and Political Science
- Manufacturing Process and Optimization
- 3D IC and TSV technologies
- Plasma Diagnostics and Applications
- Nuclear Physics and Applications
- Laser-Plasma Interactions and Diagnostics
- Metal and Thin Film Mechanics
- Acoustic Wave Resonator Technologies
- Silicon Carbide Semiconductor Technologies
- Modular Robots and Swarm Intelligence
- Advanced Multi-Objective Optimization Algorithms
- Advanced Memory and Neural Computing
- Nuclear physics research studies
- Microfluidic and Capillary Electrophoresis Applications
- Neuroscience and Neural Engineering
- Thermography and Photoacoustic Techniques
- Semiconductor Lasers and Optical Devices
- Sensor Technology and Measurement Systems
Corporation for National Research Initiatives
1998-2022
Atomic Weapons Establishment
2021
Los Alamos National Laboratory
2012
Science Exchange (United States)
2011
MEMX (United States)
2000-2010
Massachusetts Institute of Technology
1990-2003
Case Western Reserve University
1995-2002
Newberry College
1989
Micropumps capable of precise handling low-fluid volumes have the potential to revolutionize applications in fields such as drug delivery, fuel injection, and micrototal chemical analysis systems (/spl mu/TAS). Traditional microactuators used micropumps suffer from low strokes and, a result, are unsuitable for achieving large fluid displacement. They also low-actuation work densities, which translate forces. We investigate use shape-memory effect (SMA) sputter-deposited thin-film alloy...
The shape-memory effect is a solid state phenomenon which exploits reversible phase transformation to repeatedly achieve an initial shape, even after some deformation of the material. Numerous metal alloys exhibit this effect. One most widely used TiNi, due its large range recoverable deformations and relative ease processing. In bulk wire form, TiNi has been applied number applications, as thin film, excellent material for use microactuator in microelectromechanical systems (MEMS), recovery...
We introduce a novel integrable and electrostatic microvalve for the purpose of enabling pneumatic refreshable Braille display system (RBDS). Physical design parameters such as orifice size, beam length, number beams profile are experimentally explored found promising use with RBDS. Particularly, one an 70 μm×70 μm, length 665 count 20 is electrostatically closed against differential pressure 82.7 kPa applied voltage 68 V-rms. Also introduced steady-state mechanical model established on...
A new microvalve structure designed to enhance the limited actuation forces available in microfabricated devices by using a pressure-balancing scheme is reported. The concept allow fluid provide balancing force on moving part of device, thereby reducing required open valve. Various methods can be used actuate valve, but electrostatic chosen since it readily integrated with valve fabrication sequence. process for implementing uses multiple wafer bonding steps (three present prototype) and has...
A new deuterium-tritium (D-T) fusion gamma-to-neutron branching ratio [3H(d,γ)5He/3H(d,n)4He] value of (4.2 ± 2.0) × 10−5 was recently reported by this group [Y. Kim et al. Phys. Rev. C (submitted)]. This measurement, conducted at the OMEGA laser facility located University Rochester, made for first time using inertial confinement (ICF) plasmas. Neutron-induced backgrounds are significantly reduced in these experiments as compared to traditional beam-target accelerator-based due short pulse...
Three fabrication issues related to the design and of micromechanical devices using sealed cavities within bonded silicon wafers are discussed. The first concerns resultant residual gas pressure a cavity between two after bonding high-temperature anneal. second prediction plastic deformation in capping layers single-crystal over cavities. Exposure structures environment causes trapped expand, which can result layer. A model for analytically predicting occurrence deformatio these has been...
Recent success of microelectromechanical systems (MEMS) in projection displays have raised similar expectation for an efficient, low power, affordable, full-page and pneumatic tactile display. Such design has not been achieved by the conventional technology but could bring significant improvement to current refreshable Braille displays. This paper demonstrates a novel bulk-micromachined electrostatic microvalve suitable The microvalve, silicon perforated diaphragm juxtaposed inlet orifice,...
The authors report on the design, fabrication, and testing of a threshold pressure switch with mechanical hysteresis. expansion trapped gas in sealed cavity formed by wafer bonding is used to plastically deform thin silicon membrane bonded over cavity, creating spherically shaped cap. This deformed cap exhibits hysteresis its deflection versus characteristics at point buckling. It this buckling phenomenon which produce switch. describe fabrication devices as well model predict onset plastic...
The deuterium-tritium (D-T) \ensuremath{\gamma}-to-neutron branching ratio [${}^{3}$H($d$,\ensuremath{\gamma})${}^{5}$He/${}^{3}$H(d,n)${}^{4}$He] was determined under inertial confinement fusion (ICF) conditions, where the center-of-mass energy of 14--24 keV is lower than that in previous accelerator-based experiments. A D-T value (4.2 \ifmmode\pm\else\textpm\fi{} 2.0) \ifmmode\times\else\texttimes\fi{} 10${}^{\ensuremath{-}5}$ by averaging results two methods: (1) a direct measurement ICF...
The shape memory alloy (SMA) titanium-nickel (TiNi) is used in thin film form as the basis of actuation for a reciprocating micropump. A novel configuration comprising two complementary TiNi actuators to perform cyclic motion by utilizing effect (SME). Check valves are fabricated from polyimide ensure unidirectional flow through pump chamber. driven an electrical drive signal, which passed directly films, causing Joule heating-induced phase transformation and initiating SME. Cyclic achieved...
This paper reports research performed on developing and optimizing a process recipe for the plasma etching of deep high-aspect ratio features into fused silica (fused quartz) material using an inductively coupled reactive-ion etch process. As part this effort, we design experiments (DOE), wherein parameters having most impact were varied over fixed ranges predetermined values, while other unchanged. Subsequently, etched samples analyzed so as to quantify outcomes. Using experimental data...
The application of shape memory alloy (SMA) thin films in optical devices is introduced and explored for the first time. Physical properties titanium-nickel (TiNi) SMA change as these undergo phase transformation on heating. An beam can be modulated either mechanically with a TiNi actuator or by changes that occur TiNi's upon heating transformation. Reflection coefficients were measured their so-called martensitic (room-temperature) austenitic (elevated-temperature) phases. reflection higher...
Polycrystalline silicon is the most widely used structural material for surface micromachined microelectromechanical systems (MEMS). There are many advantages to using thick polysilicon films; however, due process equipment limitations, these devices typically fabricated from films less than 3 /spl mu/m thick. In this work, test structures were designed and processed (up 10 mu/m) undoped in situ boron-doped films. The elastic moduli of doped 150/spl plusmn/30 GPa, appeared be independent...
The $R$-matrix analysis of $A=5$ nuclear systems has been partially validated by applying the technique to $^{5}\mathrm{Li}$ system and comparing predicted $\ensuremath{\gamma}$-ray spectrum with historical data. similar $^{5}\mathrm{He}$ was then used predict spectral shape for deuterium-tritium (DT) reaction. resulting spectra have in DT implosions on Omega laser where interaction rate measured a gas Cherenkov detector. Comparison predictions experiment confirmed presence both 16.75...
This paper reports research performed on developing and optimizing a process recipe for the plasma etching of deep high-aspect ratio features into silicon carbide (SiC) material using an inductively-coupled reactive-ion etch process. We design experiments (DOE) wherein parameters having most impact were varied over fixed ranges predetermined values, while other unchanged. Subsequently, etched samples analyzed so as to quantify outcomes. Using experimental data collected during DOE, we then...
The authors report the complete fabrication and packaging process which yields functional pressure-balanced microvalves results on fluidic behavior of valve using pneumatic actuation. to implement uses three silicon wafer bonding steps form structure. is packaged by anodically a machined glass part having appropriately sized inlet outlet ports top surface microvalve. A chrome/platinum layer side prevents plunger from so that can be successfully actuated. Flow rates up 120 ml/min were...
This paper reports a previously unreported anomaly that occurs when attempting to perform deep, highly anisotropic etches into fused silica using an Inductively-Coupled Plasma (ICP) etch process. Specifically, it was observed the top portion of etched features exhibited substantially different angle compared vertical sidewalls would be expected in typical has been termed as “faceting.” A possible explanation mechanism causes this effect and method eradicate developed. Additionally, eliminate...
A thermally isolated microstructure for use in metal-oxide gas sensing applications was fabricated and tested. Using the techniques of bulk micromachining, a thin silicon membrane 5 mu m thick then used as structural support during subsequent device processing. The mechanical stability found to be dependent on compressive surface-oxide thickness which induced buckling. study buckling criteria examined detail by performing etch-back experiments series sequentially sized membranes observing...