基于单片机的数字时钟设计--外文翻译(15)

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.

10Low-NoiseElectronicImagingwithDouble-GateFETs23310.3CCDImageSensorwithDouble-GateFET

ChargeDetector

ThepixelsizeoftheCCDimagesensorhasbeenmadesmallertoreducechipsizeforsmallopticalassemblyandtorealizemegapixelsensorsforHDTVcameras.Itisnotacceptable,however,tocompromisethesensorperformanceforasmallercellsize,andinparticular,thesensitivityandthedynamicrangeremainhigh[1].Incontrast,theburied-channelcharge-coupleddeviceachievescompletechargetransferwithnotransfernoise.Therefore,almostallsolid-stateimagesensorsutilizelow-noiseburied-channelCCDforscanningcircuits.

Inthefollowingwedescribea1/3-ininterlinetransferCCDareaimagesensorwith94-dBdynamicrangeand1.0-electronrmsnoise oatingsurfacedetector.Withcapacitance-couplednegative-feedbackcon guration,thesaturationlevelofthedetectorissuccessfu1lyextendedbyafactorof5,maintainingthesuperiorlow-noisecharacteristics.Moreover,1=fnoiseintheoutputsignal,whichisaveryconspicuousstreaknoiseinthereproducedimageinspiteofitslow-noisepower,issuccessfullysuppressedwithanovelso-calledalternategaininversion(AGI)signalprocessingtechnique.

10.3.1SensorConstruction

Figure10.19showsphotographsofthefabricateddevicechipandthedetectiontransistor.Thechipsizeis7.1mm.H/ 5:1mm(V),andtheimagesizeis

4.8mm.H/ 3:6mm(V),whichissuitablefora1/3-inlensformat.ThedeviceisthemostpopularinterlinetransferCCDcon gurationatpresent,whichconsistsofphotodiodes,verticalCCDs(V-CCDs),andahorizontalCDD(H-CCD).Forlowleakagecurrentnoise,theburiedphotodiodestructure,whichhasahighconcentrationpC-layeronthen-typestorageregion,isadopted[7,8].ThechargedetectorattheendoftheH-CCDisadouble-gate oatingsurfacedetectorwithaneffectivereadoutnoiseof1.0electronrms.Adynamicrangeof94dBisobtainedbyreturningtheinvertedvoltagesignalontoafeedbackgate.Thesaturationnumberofelectronsisextendedto5 104electrons,whichcorrespondstothesaturationchargeofthephotodiode.

Thedeviceisfabricatedinashallowp-wellonann-typesubstrateof47 cmresistivitywith1:0 m nepatterndesignrule.Twoion-implantationprocessesareaddedtotheconventionalCCDfabricationprocess.Oneisahigh-energyphosphorousimplantationforthesensingchannel,andtheotherisasource/drainboronimplantationfortheP-channeldetectiontransistor.

百度搜索“70edu”或“70教育网”即可找到本站免费阅读全部范文。收藏本站方便下次阅读，70教育网，提供经典教育范文基于单片机的数字时钟设计--外文翻译(15)在线全文阅读。