Study of noise in CID array systems

A detailed description of CID image sensing and the various readout techniques is given. The results of theoretical and experimental studies of temporal and fixed pattern noise that affects CID imager performance are presented. The effects of feedback on amplifier noise charge are derived. A short study on the low frequency noise of buried channel MOSFETs was also performed. The use of multiple non-destructive readout operations and off-chip signal summation was used to demonstrate more than a factor of 10 improvement in signal-to-noise ratio. No intrinsic limitation on the dynamic range improvement that can be obtained with this technique was identified. External limitations such as the time available for readout have prevailed to date. Standard CID imager noise levels were evaluated. The dynamic range measured varied between 500-to-1 for the TV compatible Pre-injection readout technique to over 30,000-to-1 for a cooled Row Readout array operating at low video rates. Uncorrected signal-to-RMS fixed pattern noise ranged from 30-to-1 for Row Readout 1000-to-1 for Sequential Injection readout. Fixed pattern noise was suppressed to below 1 part in 30,000 with off-chip cancellation circuitry.