采用硅离子注入改进SIMOX埋氧的抗总剂量辐射性能研究

1、31 4 2007 4HIGHENERGYPHYSICSANDNUCLEARPHYSICSVol.31,No.4Apr.,2007ImprovementoftheRadiationHardnessofSIMOXBuriedOxidesbySiliconIonImplantationHEWei1,2;1)ZHANGZheng-Xuan1ZHANGEn-Xia1,2QIANCong1,2TIANHao1,2WANGXi11(ShanghaiInstituteofMicrosystemsandInformationTechnology,ChineseAcademyofSciences,Shangha

2、i200050,China)2(GraduateUniversityofChineseAcademyofSciences,Beijing100049,China)AbstractThetotaldoseresponsecharacteristicsoftheburiedoxides(BOX)inseparationbyimplantedoxygen(SIMOX)silicon-on-insulator(SOI)wafershavebeenimprovedbyimplantingsiliconionintotheBOXlayers.NMOS/SOItransistorswithenclosed-

3、gatestructurefabricatedinSIMOXwaferswereexposedto60Co-rayradiation.Thetotal-doseradiationhardnessoftheBOXlayersischaracterizedbythecurrentvoltage(I-V)measurements.TheexperimentalresultsshowthattheimplantationofsiliconionintotheBOXlayerscangreatlyreducebackchannelthresholdvoltageshifts(Vth),whichincr

4、easetheBOXlayerhardnesstototal-doseirradiation.Keywordssilicononinsulator,ionimplantation,total-doseradiationeect,thresholdvoltageshift1IntroductionDuetoburieddielectricisolation,SOICMOSde-22.1ExperimentdetailsDevicesTheNMOStransistorswerefabricatedonSIMOXviceshavesmallerleakagecurrentandhigherspeed

5、performanceandlargerdevicedensitythanconven-tionalbulksiliconCMOSdevices.However,theburiedlayersmakehardeningSOIdevicestototal-doseirradiationdicult.Thepresenceoftheradia-tioninducedtrappedholesintheburiedlayerscancauseaparasiticback-channelconductionpathforNMOS/SOI.Therefore,itisnecessarytohardenth

6、eburiedlayerssothattheSOIdevicescanoperatere-liablyinahigherradiationenvironment.ThenewresearchresultsofthehardenedSOIburiedlayersformedbysiliconionimplantationhavebeenreportedtoreducethepositivechargetrappedintheoxideduringexposuretoionizingradiation.Inthispaper,wefurtherdiscussthebasicmechanismres

7、ponsibleforthereductionofVth.Theimprovedtotal-doseradiationhardnessoftheBOXlayershasbeenobservedbysiliconionimplantationandhightemperatureanneal.124 SIMOX 389390 (HEP&NP) 31indicatethattheseentitiesaresiliconnanoclusters.Whentheseimplantedoxidesareexposedtoioniz-ingradiation,nanoclusterscausethe

8、formationofelectrontrapsintheoxide,andelectronstrappedatthesesitescancompensatethepositivechargeofthetrappedholes.Table1.0rad(Si)100krad(Si)500krad(Si)1Mrad(Si)ThecalculatedvaluesofNot.02.47883×10115.7711×10118.83531×101104.06723×10111.05013×10121.47931×1012tox×q,Themechanismisthatinsiliconionimplantedoxides,thereareentitiesthathavealargeelectroncapturecrosssection.Photoluminescencestudies5References2GiraldoA,PaccagnellaA,MinzoniA.Sol