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A force-based scanning Kelvin probe microscope has been applied to the problem of dopant profiling in silicon. Initial data analysis assumed the detected electrostatic force couples the sample and only the tip at the end of a force... more
A force-based scanning Kelvin probe microscope has been applied to the problem of dopant profiling in silicon. Initial data analysis assumed the detected electrostatic force couples the sample and only the tip at the end of a force sensing cantilever. Attempts to compare measurements quantitatively against device structures with this simple model failed. A significant contribution arises from the electrostatic force between the sample and the entire cantilever, which depends strongly upon the relative size of the tip, cantilever, and lateral inhomogeneities in the surface topography and material composition of the sample. Actual and simulated measurements which demonstrate the characteristic signature of this effect are presented.
Research Interests: Materials Engineering, Aerospace Engineering, Materials Science, Atomic Force Microscopy, Atmospheric sciences, and 9 moreMicroscope, Vacuum, Cantilever, Dopant, Electrostatic force, Atomic Force Acoustic Microscopy, Vacuum Science and Technology, Capacitive Sensing, and Kelvin probe force microscope (KPFM)
... to this work by colleagues at Redwood Microsystems (Brad Cozad, James M. Harris, Michael Selser, Hubert Dinh, Sapna Patel, and ... 21. AM Fitzgerald, RS Iyer, RH Dauskardt, and TW Kenny, Subcritical crack growth in single-crystal... more
... to this work by colleagues at Redwood Microsystems (Brad Cozad, James M. Harris, Michael Selser, Hubert Dinh, Sapna Patel, and ... 21. AM Fitzgerald, RS Iyer, RH Dauskardt, and TW Kenny, Subcritical crack growth in single-crystal silicon using micromachined specimens. J ...
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A force-based scanning Kelvin probe microscope has been used to image dopant profiles in silicon for integrated circuit devices on a submicron scale. By measuring the potential difference which minimizes the electrostatic force between a... more
A force-based scanning Kelvin probe microscope has been used to image dopant profiles in silicon for integrated circuit devices on a submicron scale. By measuring the potential difference which minimizes the electrostatic force between a probe and surface of a sample, an estimate of the work function difference between the probe and surface may be made. To the extent that this work function difference is a consequence of the dopant concentration near the sample surface, doping profiles are inferred from the measurements. An overview of the measurement technique is presented, along with several examples of resulting dopant imaging of integrated circuits.
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The analysis, design, fabrication, and testing of a thermopneumatic expansion valve to control single-phase and two-phase flow of liquids is described. The valve is normally open, and shuts off flow with low power consumption, below 0.5... more
The analysis, design, fabrication, and testing of a thermopneumatic expansion valve to control single-phase and two-phase flow of liquids is described. The valve is normally open, and shuts off flow with low power consumption, below 0.5 watt, reducing the power consumption of earlier thermopneumatic designs by a factor of ten. The device has been applied as an expansion valve to
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... LIGA [1,2] and bulk micromachined [3,4] microturbines have been investigated previously ... However, the use of surface micromachining technology to fabricate three-dimensional, integrated microstructures such as micro-turbines, free... more
... LIGA [1,2] and bulk micromachined [3,4] microturbines have been investigated previously ... However, the use of surface micromachining technology to fabricate three-dimensional, integrated microstructures such as micro-turbines, free from post-processing assembly, has been a ...
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ABSTRACT
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ABSTRACT
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Precise measurements of the lateral distribution of interface states in PMOSFETs, before and after drain-avalanche-hot-carrier (DAHC) stress, are reported. The results are analyzed in the context of simultaneous gate current and substrate... more
Precise measurements of the lateral distribution of interface states in PMOSFETs, before and after drain-avalanche-hot-carrier (DAHC) stress, are reported. The results are analyzed in the context of simultaneous gate current and substrate current measurements, and 2-D numerical simulations. Comparison of the results to similar NMOSFET measurements demonstrates that electron injection across the Si-SiO2 interface during DAHC stress creates amphoteric interface
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ABSTRACT The advent of microfluidic systems demands compact models for the description of flow in the constituent system components. The situation is analogous to the evolution of compact models for electron flow in MOSFETs, which were... more
ABSTRACT The advent of microfluidic systems demands compact models for the description of flow in the constituent system components. The situation is analogous to the evolution of compact models for electron flow in MOSFETs, which were essential for the development of integrated microelectronic systems. We develop here a compact gas flow model for microvalves, which relates valve flow to a limited but meaningful set of parameters. Specifically, these are the gas type; inlet and outlet pressures; ambient temperature; valve inlet diameter; the gap between the membrane and the valve inlet; and the coefficient of discharge of the valve inlet. The result is a simple, accurate model, appropriate for the design and analysis of microfluidic systems. We also demonstrate a characterization methodology for extracting the required model parameters from measurements of flow versus pressure and gap. This characterization has produced values for the coefficient of discharge, which match expectations based on previous theory and measurement. It has also produced a single parameter describing the effect of the gap in controlling flow, across broad ranges of valve inlet diameter, membrane-to-inlet gap, and pressure.
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... Albert K. Henning, Sapna Patel, Michael Selser, and Bradford A. Cozad Redwood Microsystems, 959 Hamilton Avenue, Menlo Park, CA ... AM Fitzgerald, RS Iyer, RH Dauskardt, and TW Kenny, Subcritical crack growth in single-crystal... more
... Albert K. Henning, Sapna Patel, Michael Selser, and Bradford A. Cozad Redwood Microsystems, 959 Hamilton Avenue, Menlo Park, CA ... AM Fitzgerald, RS Iyer, RH Dauskardt, and TW Kenny, Subcritical crack growth in single-crystal silicon using micromachined specimens. J ...
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A procedure was developed for producing thin film thermocouples (TFTC) on the contact surface of sliding mechanical components. The thermocouple devices were made from thin films of vapor-deposited copper and nickel. The measuring... more
A procedure was developed for producing thin film thermocouples (TFTC) on the contact surface of sliding mechanical components. The thermocouple devices were made from thin films of vapor-deposited copper and nickel. The measuring junctions of the thermocouples were approximately 2 μm thick and between 80 μm and 300 μm across. The TFTC devices were found to have extremely rapid (< 1 μS) response to a sudden temperature change and did not significantly disturb the heat flow from the sliding contact. It was found necessary to sandwich the TFTC between thin films of a hard, non-conducting ceramic (Al2O3 in the current work) to insulate the thermocouple electrically from the substrate and protect it during sliding.Thin film thermocouple devices were applied to the measurement of sliding surface temperatures in two cases, oscillatory dry sliding of a polymer pin on a flat surface, and uni-directional dry sliding of a ring over a flat pin surface. Results from the tests verified theoretical predictions. Presented as a Society of Tribologists and Lubrication Engineers paper at the STLE/ASME Tribology Conference in St. Louis, Missouri, October 14–16, 1991
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Entire Site, MEMS/MOEMS Components and Their Applications III (Proceedings Volume). Proceedings of SPIE Volume: 6113. ...
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The response to ionizing radiation of 23 modern programmable pacemakers and four automatic implantable cardioverter defibrillators (AICSs) using CMOS technology is presented. Proton and electron radiation of various energies and dose... more
The response to ionizing radiation of 23 modern programmable pacemakers and four automatic implantable cardioverter defibrillators (AICSs) using CMOS technology is presented. Proton and electron radiation of various energies and dose levels were used. Eight of the 17 pacemakers exposed to the photon radiation failed before 50 Gy, 4 at doses <17 Gy. Four of the six pacemakers exposed to