skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Radio frequency coupling apparatus and method for measuring minority carrier lifetimes in semiconductor materials

Abstract

An apparatus for measuring the minority carrier lifetime of a semiconductor sample using radio-frequency coupling. The measuring apparatus includes an antenna that is positioned a coupling distance from a semiconductor sample which is exposed to light pulses from a laser during sampling operations. A signal generator is included to generate high frequency, such as 900 MHz or higher, sinusoidal waveform signals that are split into a reference signal and a sample signal. The sample signal is transmitted into a sample branch circuit where it passes through a tuning capacitor and a coaxial cable prior to reaching the antenna. The antenna is radio-frequency coupled with the adjacent sample and transmits the sample signal, or electromagnetic radiation corresponding to the sample signal, to the sample and receives reflected power or a sample-coupled-photoconductivity signal back. To lower impedance and speed system response, the impedance is controlled by limiting impedance in the coaxial cable and the antenna reactance. In one embodiment, the antenna is a waveguide/aperture hybrid antenna having a central transmission line and an adjacent ground flange. The sample-coupled-photoconductivity signal is then transmitted to a mixer which also receives the reference signal. To enhance the sensitivity of the measuring apparatus, the mixer ismore » operated to phase match the reference signal and the sample-coupled-photoconductivity signal.« less

Inventors:
 [1];  [2]
  1. (Golden, CO)
  2. (Lakewood, CO)
Publication Date:
Research Org.:
Midwest Research Institute
OSTI Identifier:
874338
Patent Number(s):
US 6369603
Assignee:
Midwest Research Institute (Kansas City, MO) NREL
DOE Contract Number:  
AC36-99GO10337
Resource Type:
Patent
Country of Publication:
United States
Language:
English
Subject:
radio; frequency; coupling; apparatus; method; measuring; minority; carrier; lifetimes; semiconductor; materials; lifetime; sample; radio-frequency; antenna; positioned; distance; exposed; light; pulses; laser; sampling; operations; signal; generator; included; generate; 900; mhz; sinusoidal; waveform; signals; split; reference; transmitted; branch; circuit; passes; tuning; capacitor; coaxial; cable; prior; reaching; coupled; adjacent; transmits; electromagnetic; radiation; receives; reflected; power; sample-coupled-photoconductivity; impedance; speed; response; controlled; limiting; reactance; embodiment; waveguideaperture; hybrid; central; transmission; line; ground; flange; mixer; enhance; sensitivity; operated; phase; match; transmission line; semiconductor material; electromagnetic radiation; radio frequency; reference signal; carrier lifetime; coupling apparatus; measuring apparatus; semiconductor sample; /324/

Citation Formats

Johnston, Steven W., and Ahrenkiel, Richard K. Radio frequency coupling apparatus and method for measuring minority carrier lifetimes in semiconductor materials. United States: N. p., 2002. Web.
Johnston, Steven W., & Ahrenkiel, Richard K. Radio frequency coupling apparatus and method for measuring minority carrier lifetimes in semiconductor materials. United States.
Johnston, Steven W., and Ahrenkiel, Richard K. Tue . "Radio frequency coupling apparatus and method for measuring minority carrier lifetimes in semiconductor materials". United States. https://www.osti.gov/servlets/purl/874338.
@article{osti_874338,
title = {Radio frequency coupling apparatus and method for measuring minority carrier lifetimes in semiconductor materials},
author = {Johnston, Steven W. and Ahrenkiel, Richard K.},
abstractNote = {An apparatus for measuring the minority carrier lifetime of a semiconductor sample using radio-frequency coupling. The measuring apparatus includes an antenna that is positioned a coupling distance from a semiconductor sample which is exposed to light pulses from a laser during sampling operations. A signal generator is included to generate high frequency, such as 900 MHz or higher, sinusoidal waveform signals that are split into a reference signal and a sample signal. The sample signal is transmitted into a sample branch circuit where it passes through a tuning capacitor and a coaxial cable prior to reaching the antenna. The antenna is radio-frequency coupled with the adjacent sample and transmits the sample signal, or electromagnetic radiation corresponding to the sample signal, to the sample and receives reflected power or a sample-coupled-photoconductivity signal back. To lower impedance and speed system response, the impedance is controlled by limiting impedance in the coaxial cable and the antenna reactance. In one embodiment, the antenna is a waveguide/aperture hybrid antenna having a central transmission line and an adjacent ground flange. The sample-coupled-photoconductivity signal is then transmitted to a mixer which also receives the reference signal. To enhance the sensitivity of the measuring apparatus, the mixer is operated to phase match the reference signal and the sample-coupled-photoconductivity signal.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2002},
month = {1}
}

Patent:

Save / Share: