MIT/Lincoln Labs CCID20 W93C1 CCD Test Results
This is a phase 2 MIT/Lincoln Labs 2Kx4K CCD employing
the new backside boron implant and laser anneal process that improves QE
spatial uniformity. This is a 300 ohm-cm epi CCD.
A summary report is available.
Noteworthy points about this CCD include:
- In MIT/Lincoln tests this device was rated A. We concur
with that rating.
- The new backside processing gives this device better
QE uniformity than the phase 1 CCDs.
- This CCD is exceptionally flat.
- Other characteristics (QE, read noise, full well, etc.)
as shown in the summary report are typical. QE as a function of temperature
was measured.
Original postscript files are available from our anonymous
ftp server and these provide better resolution and clarity than is
usually possible on a web page. Here are a few figures to illustrate device
highlights:
- "Brick wall" pattern
- With the improve backside treatments the QE variations
are reduced. This image illustrates a typical pattern seen with the new
treatment.
- Serial and Parallel CTE
- CTE measurements are very good.
- Surface flatness
- This is one of the best we've seen.
The QE spatial variations (we've called
it the "brick wall" pattern) are much reduced compared to those
seen in the old phase 1 CCID20 CCDs. This image illustrates the appearance
of the pattern with the new process. This is a 256X256 pixel image illuminated
by 4000A light. Peak-to-valley variations are about 7% or less. The summary
report gives the results of some tests we
did to measure the effect of temperature on the observed QE variations
and the overall QE.
The Lincoln CCID20 design
produces excellent charge transfer efficiency. This is illustrated in the
following plot. The measured CTE is 0.9999958.
The parallel CTE is even better (0.9999985) as show in
this plot.
The peak-to-peak variation
of this device is under 3 um.
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