Abstract Virtually complete charge transfer can be achieved with charge coupleddevices(CCDs)intheburiedchannelconfigurationbecausetheburiedchannelCCDintroduces no transfer noise. However, conventional charge detectors incorporatedinto CCDs have a comparably large noise, which consists of thermal noise and 1/fnoisefromMOS transistorin theoutputchargedetectors.
230Y.
MatsunagaFig.10.14Evaluation
circuit
Fig.10.15Charge/voltageconversioncharacteristics.(a)RS,®1input,andresultantsignaloutput.(b)Ampli edoutputvoltagearoundtensignalelectrons
photographofthesignalvoltageampli edbyanexternalcircuitwhentheaveragenumberofelectronsinasignalpacketis10.Theampli edsignalisprocessedthrougha3.58MHzlow-pass ltertoremoveworthlesshigh-frequencynoise.Discretevoltagelevelscorrespondingtoaroundtenelectronsareobserved.Outputlevels,whichcorrespondtootherthantenelectrons,arecausedby uctuationoftheincidentlight.Thecharge-to-voltageconversioncharacteristicsobtainedbyobservingthediscretelevelsareshowninFig.10.16.Theconversiongainabove10electronsinFig.10.16isapproximatelythesameasthatinFig.10.12.Theconversionratioundertenelectronsshowslesslinearity.However,highresponsivityisstillmaintainedinthesmallsignalregion.
