超深亞微米NMOSFET中的熱載流子效應.pdf

1、西安電子科技大學碩士學位論文超深亞微米NMOSFET中的熱載流子效應姓名：邢德智申請學位級別：碩士專業(yè)：微電子學與固體電子學指導教師：劉紅俠20070101AbstractAbstractWiththescalingofdevicesizeintoultradeepsubmicronandnanegion，hotcarriereffectisalsoanimportantreliabilityissueinCMOScircuit，its

2、degradationmechanismsandimpactondevicecharacteristicsarediscusseddeeplyinthisdissertationFirstthebasicphysicalmechanismsandimpact—ionizationmechanismsunderlowsupplyvoltageinultra—deepsubmicronNMOSFET’SareintroducedThedeg

3、radationofNMOSFET’SIVcharacterandstaticparametersunderhotcarrierstressconditionarepresentedThesaturationeffectofdevicedegradationisinvestigatedTheworstcasestressconditionisalsodiscussedThreegroupsofNMOSFETwithdifferentox

4、idethicknessaremeasuredtostudythesubstratecurrentcharacteristicsIt’SexperimentallydemonstratedthatthemaximumsubstratecurrentstressconditionswishfromVgs≈l／2VdstoVgs=VasinNMOSFETwhosechannellengthis0091xm，theoxidethickness

5、is124nmItisfoundthatinshortchannelthingateoxideNMOSFETthedevicelifetimeunderchannelhotcarderstressislowerthanthatunderdrainavalanchehotcarrierstress，contrarytotheusualthinkingthattheworstcasestressconditiondependsonthega

6、tevoltagewiththemaximumsubstratecurrent，thereasonsofthisphenomenonareanalyzedAtlast，themechanismsandcharacteristicsoftrapassistedtunnelingdrainleakagecurrent(ITAT)degradationareinvestigatedBothinterfacetrapandoxidetrappe

7、dchargeareanalyzedTheexperimentalresultsshowthatthehotcarrierstressmakesITATdegradationhaveastrongdependenceontheoxidethicknessInthingateoxide(theoxidethicknesstox=384nm)NMOSFETITATdegradationisattributedmostlytointerfac

8、etrapcreation，whileinthickeroxide(theoxidethicknesstox=764nm)NMOSFETITATexhibitstwostagesdegradation，apowerlawdegradationrateintheinitialstageduetointerfacetrapgeneration，followedbyanaccelerateddegradationrateinthesecond