Effect of carbon on oxygen precipitation in silicon

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1、EffectofcarbononoxygenprecipitationinsiliconQ.Sun,a)K.H.Yao,b)J.Lagowski,andH.C.GatosMassachusettsInstituteofTechnology,Cambridge,Massachusetts02139(Received16October1989;acceptedforpublication15January1990)AsystematicFourier-transformedinfrared-spectroscopyst

2、udyofoxygenandcarboninisolatedformandascomplexesinthesiliconlatticehasrevealedadirectcorrelationbetweenthedecreaseofsubstitutionalcarbonconcentrationandthedecreaseofinterstitialoxygenconcentrationduring750°Cannealing.Ataconcentrationexceeding2ppma(partspermill

3、ionatomicpercentage),carbonwasalsofoundtoenhanceoxideprecipitategrowth.Aftercompletingathree-stepannealing(1100·C+750·C+1000·C),anoxide-precipitate-relatedIR-absorptionbandwasobserved.ThechangesoftheIR-absorptionbandwerecorrelatedwithannealing-inducedchangesin

4、thestateofcarbon.Adirectincorporationofcarbonintooxideprecipitates,and/orcarboninteractionwithsiliconself-interstitialsgeneratedduringoxygenprecipitation,aresuggestedtohaveaneffectonreducinglatticestrainassociatedwiththeoxygen-precipitationprocess.I.INTRODUCTI

5、ONII.EXPERIMENTALPROCEDURESOxygenandcarbonareunintentionalimpuritiesinSiCZ-Sicrystalswithintentionallydopedcarbonimpuri•crystalsgrownbytheCzochralski(CZ)method.Theyhavetyvaryingfrom5to30ppma(ASTM81)andinitialoxygenbeenextensivelystudiedinconjunctionwithheattre

6、atmentsconcentrationfrom1to22ppma(ASTM80)wereem•usedindeviceprocessing.1-4Eachoftheseimpuritiesaffectsployedforsinglestepannealingschedules(1)750°Cfor100thebehavioroftheother.However,theexactmechanismofh,(2)l000·Cfor64h,and(3)13OO·Cfor2hinnitrogen48theirintera

7、ctionremainsacontroversialissue.-Thehy•ambient.Anothergroupofsampleswithcarbonconcentra•pothesisofcarbonactingasheterogeneousnucleationtionrangingfromlessthan0.2to10ppmaandanoxygencentersforoxygenprecipitationimpliedanenhancedoxideconcentrationof11-19ppma(asgi

8、veninTableI)wereusedprecipitation,1.9.andacorrespondinginterstitialoxygen•foratypicalthree-stepintrinsicgetteringschedule(1100°Cconcentrationreductioninmaterialswithhighcarboncon