Radio frequency coupling apparatus and method for measuring minority carrier lifetimes in semiconductor materials
- Golden, CO
- Lakewood, CO
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.
- Research Organization:
- Midwest Research Institute, Kansas City, MO (United States)
- DOE Contract Number:
- AC36-99GO10337
- Assignee:
- Midwest Research Institute (Kansas City, MO)
- Patent Number(s):
- US 6369603
- OSTI ID:
- 874338
- Country of Publication:
- United States
- Language:
- English
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Apparatus for measuring minority carrier lifetimes in semiconductor materials
Apparatus and method for measuring minority carrier lifetimes in semiconductor materials
Related Subjects
frequency
coupling
apparatus
method
measuring
minority
carrier
lifetimes
semiconductor
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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
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