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Displaying 376 - 400 of 718

Long-Term Stability Test System for High-Voltage, High-Frequency SiC Power Devices

February 25, 2007
Author(s)
Tam H. Duong, David Berning, Allen R. Hefner Jr., Keyue M. Smedley
This paper presents test system developed for long-term stability characterization of 10 kV Silicon Carbide (SiC) power MOSFETs and SiC diodes under 20 kHz hard switching conditions. The system is designed to operate a single power switch and a single

TEM Horn Antenna Design Principles

January 23, 2007
Author(s)
Chriss A. Grosvenor, Robert T. Johnk, David R. Novotny, Nino Canales, Benjamin Davis, Jason Veneman
The National Institute of Standards and Technology has developed several ultra-wideband, TEM Horn antennas with phase linearity, short impulse duration, and a near constant antenna factor. These are time-domain antennas used to measure impulsive fields

Complex permittivity measurements of planar building materials using a UWB free-field antenna measurement system

January 1, 2007
Author(s)
Ben N. Davis, Chriss A. Grosvenor, Robert T. Johnk, David R. Novotny, James R. Baker-Jarvis, Michael D. Janezic
Building materials are often incorporated into complex, multi-layer macrostructures that are simply not amenable to measurements using coax or waveguide sample holders. In response to this, an ultra-wideband free-field measurement system has been developed

Strain-Induced Grain Growth during Rapid Thermal Cycling of Aluminum Interconnects

January 1, 2007
Author(s)
Robert Keller, Roy H. Geiss, Nicholas Barbosa, Andrew Slifka, David T. Read
We demonstrate by use of automated electron backscatter diffraction (EBSD) the rapid growth of grains in non-passivated, sputtered Al-1Si interconnects during 200 Hz thermal cycling induced by alternating electric current. Mean grain diameters were

Dynamic Lorentz Microscopy of Micromagnetic Structure in Magnetic Tunnel Junctions

November 20, 2006
Author(s)
Justin Shaw, R.H. Geiss, Stephen E. Russek
Lorentz microscopy was used to study the micromagnetic structure and magnetization reversal in magnetic tunnel junctions (MTJs) fabricated with different processing conditions including a preoxidation process. The authors find that the free layer in a MTJ

Modeling MEMS Microhotplate Structures With SystemC

October 25, 2006
Author(s)
Ankush Varma, Muhammad Afridi, Akin Akturk, Paul Klein, Allen R. Hefner Jr., Bruce Jacob
Designers of SoCs with non-digital components, such as analog or MEMS devices, can currently use highlevel system design languages, such as SystemC, to model only the digital parts of a system. This is a significant limitation, since it makes key system

Single Photon Detector Comparison in a Quantum Key Distribution Link Testbed

October 25, 2006
Author(s)
Jonathan L. Habif, David S. Pearson, Robert Hadfield, Robert E. Schwall, Sae Woo Nam, Aaron J. Miller
We provide a direct comparison between the InGaAs avalanche photodiode (APD) and the NbN superconducting single photon detector (SSPD) for applications in fiber-based quantum cryptography. The quantum efficiency and dark count rate were measured for each

Generalized Test Bed for High-Voltage, High-Power SiC Device Characterization

October 1, 2006
Author(s)
David W. Berning, Allen R. Hefner Jr., J J. Rodriguez, Colleen E. Hood, Angel Rivera
A generalized 25 kV test bed developed to characterize high-voltage, high-power SiC devices is described. The test bed features containment of all high voltage circuits and the device under test (DUT) within a clear plastic interlocked safety box. A fast

Recent Advances in High-Voltage, High-Frequency Silicon-Carbide Power Device

October 1, 2006
Author(s)
Allen R. Hefner Jr., Ryu Sei-Hyung, Hull Brett, David W. Berning, Colleen E. Hood, Jose M. Ortiz-Rodriguez, Angel Rivera-Lopez, Tam H. Duong, Adwoa Akuffo, Madelaine H. Hernandez
The emergence of High-Voltage, High-Frequency (HV-HF) Silicon-Carbide (SiC) power devices is expected to revolutionize commercial and military power distribution and conversion systems. The DARPA Wide Bandgap Semiconductor Technology (WBST) High Power

On-Wafer Noise-Parameter Measurements at NIST

July 14, 2006
Author(s)
James P. Randa, Dave K. Walker
NIST has developed the capability to measure noise parameters on a wafer int he 1-12.4 GHz range. In this paper we briefly describe the measurement methods and the uncertainty analysis and present results of measurements on a very poorly matched transistor

Terahertz radiometer design for traceable noise-temperature measurements

July 14, 2006
Author(s)
Eyal Gerecht, Dazhen Gu, James P. Randa, Dave K. Walker, Robert L. Billinger
We report on design of a radiometer for traceable noise-temperature measurements at terahertz frequencies, including noise measurements on cryogenic IF components, development and test of quasi-optical adapter technology, development of black body

Computer-Controlled Characterization of High-Voltage, High-Frequency SiC Devices

July 1, 2006
Author(s)
Jose M. Ortiz-Rodriguez, Allen R. Hefner Jr., David W. Berning, Colleen E. Hood, S. Olcum
Silicon carbide (SiC) power devices have begun to emerge recently with a performance that is superior to that of silicon power devices. Therefore, the push to higher power and higher voltage applications also comes with it. This work addresses the need for

New reference standards and artifacts for nanoscale physical property characterization

July 1, 2006
Author(s)
Jon R. Pratt, John A. Kramar, Gordon Shaw, Richard Gates, Paul Rice, John M. Moreland
This paper provides an overview of calibration artifacts being developed at the National Institute of Standards and Technology (NIST) that are intended to aid the accurate determination of nanoscale physical properties across a broad range of applications

Reverse Noise Measurement and Use in Device Characterization

June 10, 2006
Author(s)
James P. Randa, Tom McKay, Susan L. Sweeney, Dave K. Walker, Lawrence Wagner, David R. Greenberg, Jon Tao, G. Ali Rezvani
We review the concept of reverse noise measurements in the context of on-wafer transistor noise characterization. Several different applications of reverse noise measurements are suggested and demonstrated. Reverse measurements can be used to check

10 kV, 5A 4H-SiC Power DMOSFET

May 1, 2006
Author(s)
Sei-Hyung Ryu, Sumi Krishnaswami, Hull Brett, James Richmond, Anant Agarwal, Allen R. Hefner Jr.
In this paper, we report 4H-SiC power DMOSFETs capable of blocking 10 kV. The devices were scaled up to 5 A, which is a factor of 25 increase in device area compared to the previously reported value. The devices utilized 100 υm thick n-type epilayers with

Status of High-Voltage, High-Frequency Silicon-Carbide Power Devices

March 22, 2006
Author(s)
Allen R. Hefner Jr.
The emergence of High-Voltage, High-Frequency (HV-HF) Silicon-Carbide (SiC) power devices is expected to revolutionize commercial and military power distribution and conversion systems. The DARPA Wide Bandgap Semiconductor Technology (WBST) High Power

Precision Measurement Method for Cryogenic Amplifier Noise Temperatures Below 5 K

March 1, 2006
Author(s)
James P. Randa, Eyal Gerecht, Dazhen Gu, Robert L. Billinger
We report precision measurements of the effective input noise temperature of a cryogenic (liquid helium temperature) MMIC amplifier at the amplifier reference planes within the cryostat. A method is given for characterizing and removing the effect of the

Reliability and Performance Limitations in SiC Power Devices

December 27, 2005
Author(s)
Ranbir Singh, Allen R. Hefner Jr.
Despite Silicon Carbide's (SiC's) high breakdown electric field, high thermal conductivity and wide bandgap, it faces certain reliability challenges when used to make conventional power device structures like power MOS-based devices, bipolar-mode diodes

Electromagnetic Signatures of WLAN Cards and Network Security

December 21, 2005
Author(s)
Catherine A. Remley, Chriss A. Grosvenor, Robert T. Johnk, David R. Novotny, Paul D. Hale, Michael McKinley, Emmanouil Antonakakis, A Karygiannis
The proliferation of wireless devices and the availability of new wireless applications and services raise new privacy and security concerns. Although network-layer anonymity protects the identities of the communication endpoints, the physical layer of
Displaying 376 - 400 of 718