Low frequency electromigration noise and film microstructure in Al/Si stripes: Electrical measurements and TEM analysis

1993 ◽  
Vol 22 (11) ◽  
pp. 1323-1326 ◽  
Author(s):  
C. Ciofi ◽  
A. Diligenti ◽  
F. Giacomozzi ◽  
A. Nannini ◽  
B. Neri
Keyword(s):  
Low Frequency ◽  
Electrical Measurements ◽  
Tem Analysis ◽  
Film Microstructure

Radio and Electrical Measurements on Glacial Streams

1987 ◽  
Vol 33 (114) ◽  
pp. 239-242
Author(s):  
M. E. R. Walford
Keyword(s):  
Electrical Conductivity ◽  
Water Channel ◽  
Water System ◽  
Low Frequency ◽  
Water Channels ◽  
Radiative Loss ◽  
Radio Waves ◽  
Electrical Measurements ◽  
Water Conductivity ◽  
Glacier Surface

AbstractWe discuss the suggestion that small underwater transmitters might be used to illuminate the interior of major englacial water channels with radio waves. Once launched, the radio waves would naturally tend to be guided along the channels until attenuated by absorption and by radiative loss. Receivers placed within the channels or at the glacier surface could be used to detect the signals. They would provide valuable information about the connectivity of the water system. The electrical conductivity of the water is of crucial importance. A surface stream on Storglaciären, in Sweden, was found, using a low-frequency technique, to have a conductivity of approximately 4 × 10−4 S m−1. Although this is several hundred times higher than the conductivity of the surrounding glacier ice, the contrast is not sufficient to permit us simply to use electrical conductivity measurements to establish the connectivity of englacial water channels. However, the water conductivity is sufficiently small that, under favourable circumstances, radio signals should be detectable after travelling as much as a few hundred metres along an englacial water channel. In a preliminary field experiment, we demonstrated semi quantitatively that radio waves do indeed propagate as expected, at least in surface streams. We conclude that under-water radio transmitters could be of real practical value in the study of the englacial water system, provided that sufficiently robust devices can be constructed. In a subglacial channel, however, we expect the radio range would be much smaller, the environment much harsher, and the technique of less practical value.

WORKING DEPTHS FOR LOW FREQUENCY ELECTRICAL PROSPECTING

Geophysics ◽  
1945 ◽  
Vol 10 (1) ◽  
pp. 63-75 ◽  
Author(s):  
William Bradley Lewis
Keyword(s):  
Low Frequency ◽  
Electrical Measurements ◽  
The Earth ◽  
Electrical Prospecting

Electrical measurements were made on the surface of the earth with low frequency commutated current using nineteen separate frequencies and six electrode separations. Analysis of the data indicates that there is an effect of appreciable magnitude attributable to an interface 6000 feet below the surface.

The origin of the observed low-frequency electrical polarization in sandstones

Geophysics ◽  
2006 ◽  
Vol 71 (5) ◽  
pp. G235-G238 ◽  
Author(s):  
Julian B. Scott
Keyword(s):  
Double Layer ◽  
Electrical Double Layer ◽  
Ionic Composition ◽  
Low Frequency ◽  
Ionic Mobility ◽  
Electrical Measurements ◽  
Pore Throat ◽  
Polarization Model ◽  
Electrical Relaxation ◽  
Water Saturated

There has been an increasing debate regarding the mechanism controlling the low-frequency polarization (megahertz to kilohertz) in sandstones. The polarization and related electrical relaxation are extremely important because they can be used to provide a significant amount of information on length scales within the sandstone. Complex electrical measurements, in the mHz to kHz range, were made on gel-filled samples. This gel decreases the ionic mobility in the bulk pore fluid while keeping the ionic composition similar to that in a water-saturated sample. The presence of the gel was shown to have little effect on the electrical relaxation. This adds to the argument that the electrical double layer close to the grain surface is where the polarization originates. The correlation between pore-throat size and the relaxation time is consistent with the polarization mechanism of ion diffusion within the electrical double layer. The membrane-type polarization model, used previously to explain the polarization in pore-throat regions, is likely to be incorrect because of the relative thinness of the electrical double layer.

Degradation and Reliability of Bare Dies Operated up to 300°C

2015 ◽  
Vol 821-823 ◽  
pp. 681-684
Author(s):  
Dean Hamilton ◽  
M. Jennings ◽  
Stephen York ◽  
Steven A. Hindmarsh ◽  
Y. Sharma ◽  
...  
Keyword(s):  
Cross Sections ◽  
Mechanical Degradation ◽  
Electrical Characteristics ◽  
Isothermal Heating ◽  
Electrical Measurements ◽  
Tem Analysis ◽  
Metal Layers ◽  
State Resistance ◽  
Contact Metal

In this paper, we demonstrate the degradation of commercially available 1.2kV SiC MOSFET bare dies subjected to long periods of isothermal heating at 300°C in air. Periodic electrical measurements indicated an increase in on-state resistance to different extents for three different vendor designs, and the discovery of a progressive rectifying type forward characteristic at low drain-source voltages. Subsequent investigations to determine the cause of the degraded electrical characteristics including sectioning and SEM/TEM analysis revealed some mechanical degradation within the device gate-source cross-sections and backside drain contact metal layers. While one vendor device was severely degraded after approximately 24 hours of heating, another vendor device was only just beginning to degrade after 100 hours, indicating that these devices may be used successfully in real applications at 300°C junction temperatures for relatively long periods.

Characterization of N-Type Layers Formed in Si by Ion Implantation of Hydrogen

1983 ◽  
Vol 27 ◽  
Author(s):  
S. R. Wilson ◽  
W. M. Paulson ◽  
W. F. Krolikowski ◽  
D. Fathy ◽  
J. D. Gressett ◽  
...  
Keyword(s):  
Background Concentration ◽  
Donor Concentration ◽  
Electrical Measurements ◽  
Tem Analysis ◽  
Cross Sectional ◽  
Projected Range ◽  
Residual Damage ◽  
Donor Formation ◽  
C 30

ABSTRACTSilicon wafers have been implanted with H+ (90 keV) to doses of 5.0E15/ cm2 and 2.OE16/cm2. The wafers were annealed in nitrogen at temperatures between 450 and 700°C for times between 10 and 60 min. The electrically active carrier profiles were measured by capacitance voltage and spreading resistance techniques. The residual damage was measured by TEM and RBS. The electrical measurements were essentially the same in both FZ and CZ silicon implying that oxygen is not playing a role in the donor formation which was observed. The donor concentration peaks near the projected range of the hydrogen after annealing at temperatures between 450–500°C. As reported previously 1000 H+ ions generate 1 donor in the implant peak. In addition, the donor concentration between the surface and Rp has increased more than a factor of 10 above the background concentration after a 450°C 10 min anneal. Anneals of 550°C for 30 min or more annihilates essentially all of the donors. The RBS results show small amounts of damage for the 5.0E15/cm2 implant dose but considerable crystal damage with a dose of 2.0E16/cm2, even after a 500°C, 30 min anneal. Cross-sectional TEM analysis of 500°C annealed samples showed a large number of small loops at depths corresonding to the depth of the peak electrical carrier concentration. The donors are directly correlated to the implant damage and resultant defects. SIMS data shows little diffusion for anneals of 500°C or less but after 550°C, 30 min the peak H concentration decreases by approximately a factor of 10.

scholarly journals Impedance Analysis and Noise Measurements on Multi Walled Carbon Nanotube Networks

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7509
Author(s):  
Usha Philipose ◽  
Yan Jiang ◽  
Brianna Western ◽  
Michael Harcrow ◽  
Chris Littler ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Low Frequency ◽  
Impedance Analysis ◽  
Frequency Range ◽  
Electrical Measurements ◽  
Electrical Equivalent Circuit ◽  
Host Matrix ◽  
Multi Walled Carbon Nanotube ◽  
Frequency Independent ◽  
Noise Measurements

The electrical impedance characteristics of multi-walled carbon nanotube (MWCNTs) networks were studied as a function of CNT concentrations in the frequency range of 1 kHz–1 MHz. The novelty of this study is that the MWCNTs were not embedded in any polymer matrix and so the response of the device to electrical measurements are attributed to the CNTs in the network without any contribution from a polymer host matrix. Devices with low MWCNT packing density (0.31–0.85 µg/cm2) exhibit a frequency independent plateau in the low-frequency regime. At higher frequencies, the AC conductivity of these devices increases following a power law, characteristic of the universal dynamic response (UDR) phenomenon. On the other hand, devices with high MWCNT concentrations (>1.0 µg/cm2) exhibit frequency independent conductivity over the entire frequency range (up to 1 MHz), indicating that conduction in these devices is due to direct contact between the CNTs in the network. A simple single-relaxation time electrical equivalent circuit with an effective resistance and capacitance is used to describe the device performance. The electrical noise measurements on devices with different MWCNT packing densities exhibit bias-dependent low-frequency 1/f noise, attributed to resistance fluctuations.

Radio and Electrical Measurements on Glacial Streams

1987 ◽  
Vol 33 (114) ◽  
pp. 239-242 ◽  
Author(s):  
M. E. R. Walford
Keyword(s):  
Electrical Conductivity ◽  
Water Channel ◽  
Water System ◽  
Low Frequency ◽  
Water Channels ◽  
Radiative Loss ◽  
Radio Waves ◽  
Electrical Measurements ◽  
Water Conductivity ◽  
Glacier Surface

AbstractWe discuss the suggestion that small underwater transmitters might be used to illuminate the interior of major englacial water channels with radio waves. Once launched, the radio waves would naturally tend to be guided along the channels until attenuated by absorption and by radiative loss. Receivers placed within the channels or at the glacier surface could be used to detect the signals. They would provide valuable information about the connectivity of the water system. The electrical conductivity of the water is of crucial importance. A surface stream on Storglaciären, in Sweden, was found, using a low-frequency technique, to have a conductivity of approximately 4 × 10−4S m−1. Although this is several hundred times higher than the conductivity of the surrounding glacier ice, the contrast is not sufficient to permit us simply to use electrical conductivity measurements to establish the connectivity of englacial water channels. However, the water conductivity is sufficiently small that, under favourable circumstances, radio signals should be detectable after travelling as much as a few hundred metres along an englacial water channel. In a preliminary field experiment, we demonstrated semi quantitatively that radio waves do indeed propagate as expected, at least in surface streams. We conclude that under-water radio transmitters could be of real practical value in the study of the englacial water system, provided that sufficiently robust devices can be constructed. In a subglacial channel, however, we expect the radio range would be much smaller, the environment much harsher, and the technique of less practical value.

Modeling of Low-Frequency Downhole Electrical Measurements for Mapping Proppant Distribution in Hydraulic Fractures in Casedhole Wells

SPE Journal ◽  
2018 ◽  
Vol 23 (06) ◽  
pp. 2147-2157 ◽  
Author(s):  
Peng Zhang ◽  
Mrinal K. Sen ◽  
Mukul M. Sharma ◽  
Jeff Gabelmann ◽  
David Glowka
Keyword(s):  
Electrical Potential ◽  
Synthetic Data ◽  
Low Frequency ◽  
Electrical Current ◽  
Hydraulic Fractures ◽  
Single Fracture ◽  
Electrical Measurements ◽  
Multiple Fractures ◽  
Electrically Conductive ◽  
Simulation Results

Summary A tool concept using downhole electrical measurements for mapping electrically conductive proppant in hydraulic fractures is presented in this paper. The method relies on direct excitation of the casing, which is expected to overcome the severe limitations of induction tools in casedhole wells. An array of insulating gaps is installed and cemented in place as a permanent part of the casing string. The envisioned electrical measurements are performed by imposing a voltage across each insulating gap, one at a time, before and after hydraulic-fracture operations. The voltages across other insulating gaps near the transmitter gap are recorded. The proposed tool's response to the geometry of a single fracture was modeled by solving for the electrical potential with a finite-volume method. Previous simulation results have shown that the electrically conductive proppant alters the path of the electrical current in the formation, and this is recorded as differential signals by the string of insulating gaps surrounding the source gap. The simulated differential signals are highly sensitive to a fracture's location, length, and orientation, and less sensitive to the fracture's aspect ratio. However, to enable the implementation of such a practical system, various aspects of the tool concept must be investigated further through simulations. Following our previous work, this paper focuses on the forward modeling of the tool's response to multiple fractures, which demonstrates the influence of these fractures on the signals, and provides important guidance for inverse modeling. Parametric inversion of fractures from synthetic data, generated by exciting various insulating gaps, is solved with very fast simulated annealing (VFSA). Simulation results show that, when multiple hydraulic fractures are present, the voltages measured at the receiver gaps are determined primarily by the fracture that is in direct contact with the excited section of casing. When two fractures touch the same casing section, they induce voltages very similar to those from a single fracture with the same conductivity and volume. Preliminary inversion results that use synthetic data computed from circular fractures indicate that the proposed VFSA can solve for the multiple fractures’ widths and radii at the same time, without requiring numerous forward simulations. Even with noisy synthetic data, VFSA can make good estimates of the fractures’ parameters. This indicates that the VFSA technique is a proper and robust inversion technique for the measured voltages at various receiver gaps.

scholarly journals Estimation of In Vivo Water Content of the Stratum Corneum from Electrical Measurements

2009 ◽  
Vol 3 (1) ◽  
pp. 8-12 ◽  
Author(s):  
Gorm Krogh Johnsen ◽  
Ø.G Martinsen ◽  
S Grimnes
Keyword(s):  
Stratum Corneum ◽  
Water Content ◽  
Uniform Distribution ◽  
Concentration Profile ◽  
Low Frequency ◽  
Water Concentration ◽  
Electrical Measurements ◽  
Equilibrium Water Content

In vivo water content in the epidermal stratum corneum can be estimated by means of low frequency susceptance measurements. In the in vitro calibration necessary to find the in vivo water content, the stratum corneum will have a uniform distribution of water across its thickness. However, in vivo stratum corneum has an increasing water concentration profile from the outermost towards the innermost parts. This paper will investigate the possibility of estimating the equilibrium water content in the in vivo stratum corneum non-invasively from electrical susceptance measurements. Given a known shape of the water concentration profile in the in vivo stratum corneum and the dependence of susceptance on the water content, it is possible to calculate the water content in vivo based on analytically derived expressions for the water concentration profile. A correspondence between in vivo and in vitro water content needed for this purpose is also established.

Mapping Proppant Distribution in Hydraulic Fractures in Cased Wellbores Using Low Frequency Downhole Electrical Measurements

2018 ◽  
Author(s):  
Peng Zhang ◽  
Mrinal K. Sen ◽  
Mukul M. Sharma ◽  
Jeff Gabelmann ◽  
David Glowka
Keyword(s):  
Low Frequency ◽  
Hydraulic Fractures ◽  
Electrical Measurements
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