| MadSci Network: Engineering |
Greetings:
The term popcorn denotes a type of random shot noise and was given the
name
because of its similarity to the sound of popping corn when heard over
a
loudspeaker. Several technologies suffer from “popcorn noise”
including
operational amplifiers, thin film magnetic recording heads, motion
picture sound
tracks and various electromagnetic wave detection devices including
optical
detectors. In general popcorn noise has been related to various
problems in the
processing of semiconductor materials and in particular to their
metalization for
electrical contacts. One of the reasons that you will find that there
is little
reference to popcorn noise in the literature is that in general it is
a form of highly
filtered flicker noise (1/f noise) that rolls off at low frequencies
and does not
extend to DC. Some books call it pink noise.
A recent book that is available at Amazon.com includes a section on
the causes of
popcorn noise in general is:
T. I, Bajenescu, M. I. Bazu, T.I. , Reliability of Electronics
Components,
Springer, 1999, 509 pages.
An excellent collection of papers on the basic physics of detector
parameters,
including noise, and pyroelectric detectors, is:
F. R. Arams, Infrared to Millimeter Wavelength Detectors,
Airtech House, Inc, 1973.
The Airtech publication does discuss noise, but does not specifically
discuss popcorn
noise in pyroelectric detectors. The main focus in the development of
these devices
has been to increase the speed of response of the detectors to
higher power laser
energy and not to reducing their noise floor. In my experience,
applying uniform low
resistance, low noise contact metalization to ferroelectric and
pyroelectric materials
has been a very difficult processing problem. I will continue to look
for specific information on popcorn noise in pyroelectric devices and what
ever I find I will forward it to you.
Best Regards
Adrian Popa
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