Papers by carlos mastrangelo
We present the design, fabrication, and response of a polymer-based Laterally Amplified Chemo-Mec... more We present the design, fabrication, and response of a polymer-based Laterally Amplified Chemo-Mechanical (LACM) humidity sensor based on mechanical leveraging and parametric amplification. The device consists of a sense cantilever asymmetrically patterned with a polymer and flanked by two stationary electrodes on the sides. When exposed to a humidity change, the polymer swells after absorbing the analyte and causes the central cantilever to bend laterally towards one side, causing a change in the measured capacitance. The device features an intrinsic gain due to parametric amplification resulting in an enhanced signal-to-noise ratio (SNR). 11-fold magnification in sensor response was observed via voltage biasing of the side electrodes without the use of conventional electronic amplifiers. The sensor showed a repeatable and recoverable capacitance change of 11% when exposed to a change in relative humidity from 25-85%. The dynamic characterization of the device also revealed a respon...
Proceedings MEMS 98. IEEE. Eleventh Annual International Workshop on Micro Electro Mechanical Systems. An Investigation of Micro Structures, Sensors, Actuators, Machines and Systems (Cat. No.98CH36176)
This paper presents the design, fabrication, and testing of passive plastic microfluidic valves a... more This paper presents the design, fabrication, and testing of passive plastic microfluidic valves and active injectors driven by capillary forces. The passive valves stop the flow of a liquid inside a capillary using a capillary pressure barrier that develops when the channel cross section changes abruptly. Two types of valves with vertical and horizontal neck regions were fabricated yielding pressure barriers ranging from 1-6 kPa. Introducting asymmetry in the neck region, unidirectional valving action was achieved. The passive valving devices were used in combination with two electrodes to implement a sample injector. The injector uses an electrolytically-generated ¢ ¤ £ bubble that raises the liquid pressure beyond the barrier thus reestablishing flow with as little as 150 ¥ W of electrical power.
In this paper we present calorimetric pressure sensitive microparticles for flow field pressure m... more In this paper we present calorimetric pressure sensitive microparticles for flow field pressure measurements. Direct measurement of the absolute internal chip pressures has been achieved with these particles distributed throughout the chip implementing a particle imaging manometry (PIM) system. As a functional demonstration, the pressure distribution of a binary dilution network chip has been measured using this method.
This paper presents the design, fabrication, and testing of a two-axis 320 pixel micromirror arra... more This paper presents the design, fabrication, and testing of a two-axis 320 pixel micromirror array. The mirror platform is constructed entirely of single-crystal silicon (SCS) minimizing residual and thermal stresses. The 14-m-thick rectangular (750 800 m 2) silicon platform is coated with a 0.1-m-thick metallic (Au) reflector. The mirrors are actuated electrostatically with shaped parallel plate electrodes with 86 m gaps. Large area 320-mirror arrays with fabrication yields of 90% per array have been fabricated using a combination of bulk micromachining of SOI wafers, anodic bonding, deep reactive ion etching, and surface micromachining. Several type of micromirror devices have been fabricated with rectangular and triangular electrodes. Triangular electrode devices displayed stable operation within a (5 , 5) (mechanical) angular range with voltage drives as low as 60 V. [1124] Index Terms-Al etching, deep-reactive ion etching (DRIE), micromirrors, optical switching, silicon on insulator (SOI) wafers.
IEEE Transactions on Computer-aided Design of Integrated Circuits and Systems, 1996
This paper describes a systematic method for the automatic generation of fabrication processes of... more This paper describes a systematic method for the automatic generation of fabrication processes of thin film devices. The method uses a partially ordered set (poset) representation of device topology describing the order between its various components in the form of a directed acyclic graph. The sequence in which these components are fabricated is determined from the poset linear extensions, and the component sequence is expanded into a corresponding process flow. The graph-theoretic synthesis method is powerful enough to establish existence and multiplicity of flows thus creating a design space D suitable for optimization. The cardinality ||D|| for a device with N components is large with a worst case ||D||⩽(N-1)! yielding in general a combinatorial explosion of solutions. The number of solutions is controlled through a priori estimates of ||D|| and condensation of the device graph. The method has been implemented in the computer program MISTIC (Michigan Synthesis Tools for Integrated Circuits) which calculates specific process parameters using an internal database of process modules and materials. Currently, MISTIC includes process modules for deposition, lithography, etching, ion implantation, coupled simultaneous diffusions, and reactive growth. The compilation procedure was applied to several device structures. For a double metal twin-well BiCMOS structure, the compiler generated 168 complete process flows
A fabrication process that eliminates the adhesion of surface-micromachined suspended mechanical ... more A fabrication process that eliminates the adhesion of surface-micromachined suspended mechanical structures to the underlying substrate during a sacrificial-etch release is presented. The method is based on the construction of a periodic array of polymer columns or rubber feet that stiffen the structure during the sacrificial etch. Flat polycrystalline silicon plates measuring 3000×3000×1-μm suspended 1 μm above the substrate are easily fabricated by this method. This process has applications in the fabrication of micromachined plates used in devices such as accelerometers and pressure sensors
IEEE/ASME Journal of Microelectromechanical Systems, 1996
A capacitive surface-micromachined sensor suitable for the measurement of liquid and gas pressure... more A capacitive surface-micromachined sensor suitable for the measurement of liquid and gas pressures was fabricated. The structure consists of a polysilicon stationary electrode suspended 0.7 μm above a 20-μm-thick lightly doped silicon diaphragm formed by a patterned etch stop. The a priori patterning of the buried etch stop yields diaphragm widths independent of wafer thickness variations with excellent alignment. The
A photoresist-like thermally responsive polymer has been formulated, surface micromachined and in... more A photoresist-like thermally responsive polymer has been formulated, surface micromachined and integrated into parylene microchannels to realize an inline valve. The polymer physically swells below its lower critical solution temperature and shrinks above it. Test showed a 2.5-fold polymer volume increase by changing water temperature from 25 to 10°C. Repeated polymer swelling and shrinking were observed inside the channel with a system response time around 7 s. Pressure build-up measurements were used to demonstrate the functionality of the valve. Valve test results using DI water showed that the pressure upstream of the polymer plug increased from 15.3 to 20.3 psi with temperature change from 36°C to 15°C.
In this paper we present an experimental methodology for parametric yield estimation that account... more In this paper we present an experimental methodology for parametric yield estimation that accounts for spatial correlations between features of the same device at specific wafer locations. Each device feature is representative of a device parameter that must fit with a specific tolerance box and may be influenced by several steps of the manufacturing process. If the process how is known and each of its steps is characterized in a spatially correlated manner, the feature pointwise probability density functions (PDFs) can be accurately reconstructed from the processing step pointwise PDFs. This method thus permits the estimation of pointwise device yield more accurately than the common multilevel (run, wafer, die) averaging approach. Because spatially correlated phenomena is subject to both random and systematic nonuniformities, the pointwise step (PDFs) are determined by a decomposition process that separates the systematic and random error components. The systematic PDFs are determined from interpolation functions representing the spatial variations across the entire wafer lot, and the random PDFs are approximated using a combination of principle component analysis and factor analysis with a few uncorrelated random variables valid for the entire lot.
Electrophoresis, 2001
Electrophoresis of single-stranded DNA in denaturing polyacrylamide gels is presently a standard ... more Electrophoresis of single-stranded DNA in denaturing polyacrylamide gels is presently a standard procedure for the sequencing of DNA fragments. A thorough understanding of the factors that determine the resolution of DNA fractionated in polyacrylamide gels is necessary to optimize the performance of DNA sequencers. Significant research on the mobility of double-stranded (ds)DNA molecules in agarose and polyacrylamide gels has been performed, and the phenomenon of band broadening of single-stranded (ss)DNA fragments in DNA sequencing gels has received attention only recently. In this paper, we present a detailed study of mobility, diffusion and dispersion of ssDNA in sequencing gels as a function of molecular size, gel concentration and electric field strength. DNA mobility is shown to be essentially independent of electric field in the range of 0-60 V/cm. The band broadening is greatly enhanced in the presence of an electric field and the dispersion coefficient (DE) can be an order of magnitude higher than the field-free diffusion coefficient. The measured migration parameters approximately follow the predictions of the biased reptation including fluctuations (BRF) theory. However, deviations due to nonidealities of the separation conditions are observed. The measured migration parameters can be used to optimize the performance of separation systems.
IEEE/ASME Journal of Microelectromechanical Systems, 2002
Normally-open microvalves have been fabricated and tested which use a paraffin microactuator as t... more Normally-open microvalves have been fabricated and tested which use a paraffin microactuator as the active element. The entire structure with nominal dimension of 600 m 30 m is batch-fabricated by surface micromachining the actuator and channel materials on top of a single substrate. Gas flow rates in the 0.01-0.1 sccm range have been measured for several devices with actuation powers ranging from 50 to 150 mW on glass substrates. Leak rates as low as 500 sccm have been measured. The normally-open blocking microvalve structure has been used to fabricate a precision flow control system of microvalves consisting of four blocking valve structures. The control valve is designed to operate over a 0.01-5.0 sccm flow range at a differential pressure of 800 torr. Flow rates ranging from 0.02 to 4.996 sccm have been measured. Leak rates as low as 3.2 msccm for the four valve system have been measured.
Sensors and Actuators A-physical, 1990
3T. Hirai, K. Niihara and S. Hayashi, Chemical vapor-deposited amorphous silicon nitride, Sci. Re... more 3T. Hirai, K. Niihara and S. Hayashi, Chemical vapor-deposited amorphous silicon nitride, Sci. Rep. Res. Inst., Tohoku Univ. A26 (1987), pp. 185201. ... 5C.H. Mastrangelo and RS Muller, Thermal diffusivity of heavily doped low pressure chemical vapor deposited ...
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 1996
... 1996) 228231 NUCLEAR INSTRUMENTS METHODS IN PHYSICS RESEARCH Section A 1D position sensitive ... more ... 1996) 228231 NUCLEAR INSTRUMENTS METHODS IN PHYSICS RESEARCH Section A 1D position sensitive single carrier semiconductor detectors Zhong He", Glenn R Knoll a, David K. Wehe a, Ronald Rojeski a, Carlos H. Mastrangelo b, Mark Hammig a, Carla Barrett a ...
IEEE/ASME Journal of Microelectromechanical Systems, 2000
In this paper, a contamination-insensitive differential capacitive pressure sensor with a sealed ... more In this paper, a contamination-insensitive differential capacitive pressure sensor with a sealed gap is presented. This device is made of three polysilicon layers including a stationary middle plate and the top and bottom plates that are rigidly coupled together by a series of posts hence deflecting in tandem by a change in differential or gauge pressure. Because of the posts,
Sensors and Actuators B-chemical, 2004
This paper reports the development of epoxy microcasting technologies for the fabrication of plas... more This paper reports the development of epoxy microcasting technologies for the fabrication of plastic microfluidic platforms. Two new techniques one involving embedding active silicon devices in plastic microsystems using a polymer flip chip process and another involving surface micromachining to build active components like actuators for use in applications like pumping are discussed and explained. Application devices were fabricated for polymerase chain reaction (PCR) and capillary electrophoresis (CE).
Analytical Chemistry, 2003
Monolithic plugs of poly(N-isopropylacrylamide) cross-linked with 5% methylenebisacrylamide have ... more Monolithic plugs of poly(N-isopropylacrylamide) cross-linked with 5% methylenebisacrylamide have been prepared by photoinitiated polymerization within the channel of a microfluidic device. The volume change associated with the polymer phase transition at its lower critical solution temperature of 32 degrees C allows both the rapid swelling and the deswelling of the monoliths enabling the polymer to close or open the channel as it functions as a nonmechanical valve. Thermoelectric elements capable of changing the temperature of the system between 17 and 57 degrees C were used to actuate the valve. Flow through the device was monitored by fluorescence measurements via the laser-triggered photobleaching of a dye contained in the liquid phase. Photobleaching occurs quickly once the flow is stopped, and the time required to open and close the valve was 3.5 and 5.0 s, respectively. No changes in function were observed even after 120 open-close cycles. Although the 2-mm-long valve was prepared from a polymerization mixture consisting of only a 5% aqueous solution of monomers, it resists pressures of up to 1.38 MPa (200 psi) without observable structural damage.
A novel porous polymer was microfabricated to serve as a porous plug for a new device, the porous... more A novel porous polymer was microfabricated to serve as a porous plug for a new device, the porous plug electro-osmotic pump (pp-EOP).
Nature Biotechnology, 2008
A nanopore-based device provides single-molecule detection and analytical capabilities that are a... more A nanopore-based device provides single-molecule detection and analytical capabilities that are achieved by electrophoretically driving molecules in solution through a nano-scale pore. The nanopore provides a highly confined space within which single nucleic acid polymers can be analyzed at high throughput by one of a variety of means, and the perfect processivity that can be enforced in a narrow pore ensures that the native order of the nucleobases in a polynucleotide is reflected in the sequence of signals that is detected. Kilobase length polymers (single-stranded genomic DNA or RNA) or small molecules (e.g., nucleosides) can be identified and characterized without amplification or labeling, a unique analytical capability that makes inexpensive, rapid DNA sequencing a possibility. Further research and development to overcome current challenges to nanopore identification of each successive nucleotide in a DNA strand offers the prospect of `third generation' instruments that will sequence a diploid mammalian genome for ~$1,000 in ~24 h.
Xenon Difluoride is an isotropic dry etch which is increasingly being used to release structures ... more Xenon Difluoride is an isotropic dry etch which is increasingly being used to release structures made of polysilicon. By using a vapor-phase XeF2 pulse etching system we have investigated the effects of aperture size and thickness of polysilicon films versus etch rates. Decreasing the aperture size resulted in reduced etch rates. For a 100 μm wide structure the etch rates varied from 1.38 μm/min (1.25 μm thick polysilicon) down to 0.41 μm/min (0.1 μm thick polysilicon). Rate constants are obtained for a modified, aperture-dependent Deal-Grove model from the experimental data.
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Papers by carlos mastrangelo