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Engineering and Technical Services:...(1Sep94)
Aladdin - 1024 X 1024 InSb Array Project
(from Director's Office, NOAO Newsletter No. 39, 1 September 1994)

We have completed the warm wafer testing on the development lot of readouts
and it has been a great success. We now have yield statistics on the readout
design and processing. In summary the development lot yielded 37% perfect
(i.e. no bad rows or columns) quadrants (there are four quadrants per readout
die) and 27% good quadrants (less than 2 bad rows/columns total). Because of
grouping, due to wafer quality and processing issues, we obtained 7 perfect
1024 X 1024 readout die (~8.7%), 9 good die (~11.2%), and another 4 which
have one quadrant with 3 bad rows/columns. This gives us an overall useful
yield of 25%. Several of the die were packaged for cold testing at NOAO and
SBRC. We have completed our testing from LN2 down to 30K and the readout
functions as designed. We have tested both the PMOS and NMOS output drivers
and see very little performance difference at the bare readout level. The
final decision as to which is the better choice will have to await hybrid
testing. The gain uniformity is better than 1% and the noise at the readout
level is comparable to the 256 InSb device. A meeting was held at SBRC in
June on the Readout Development Phase of the contract and it was decided to
go to the next phase which is producing a limited number of hybrids for
further evaluation. These are expected to be in test before the end of the
summer and at the telescope soon thereafter. Watch the ALADDIN ftp directory
for the first images.

A paper, "Next Generation in InSb arrays: ALADDIN, the 1024 X 1024 InSb focal
plane array readout evaluation results" was presented at the SPIE Conference
in San Diego in July. The paper presents the first test data on the bare
readout. A copy of the paper can be obtained by contacting Carol Gregory,
cgregory@noao.edu. Work is continuing on a plan whereby the community can
participate with NOAO in a production run at SBRC of Aladdin focal plane
arrays. More will be forthcoming on this effort.

Carol Gregory

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