Freestanding thickness of single crystal material and method having carrier lifetimes.docx
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Freestandingthicknessofsinglecrystalmaterialandmethodhavingcarrierlifetimes
(31of137)
UnitedStatesPatentApplication
20100052105
KindCode
A1
Henley;FrancoisJ.; etal.
March4,2010
Free-standingthicknessofsinglecrystalmaterialandmethodhavingcarrierlifetimes
Abstract
Amethodoffabricatingathicknessofsiliconmaterialincludesprovidingasiliconingotmaterialhavingasurfaceregionandintroducingapluralityofparticleshavinganenergyofabout1-5MeVthroughthesurfaceregiontoadepthtodefineacleaveregionandathicknessofdetachablematerialbetweenthecleaveregionandthesurfaceregion.Additionally,themethodincludesprocessingthesiliconingotmaterialtofreethethicknessofdetachablematerialatavicinityofthecleaveregionandcausingformationofafree-standingthicknessofmaterialcharacterizedbyacarrierlifetimeabout10microsecondsandathicknessrangingfromabout20micronstoabout150micronswithathicknessvariationoflessthanaboutfivepercent.Furthermore,themethodincludestreatingthefree-standingthicknessofmaterialusingathermaltreatmentprocesstorecoverthecarrierlifetimetoabout200microsecondsandgreater.
Inventors:
Henley;FrancoisJ.;(Aptos,CA);Kang;Sien;(Dublin,CA);Liu;Zuqin;(PaloAlto,CA);Tian;Lu;(Milpitas,CA)
CorrespondenceAddress:
TOWNSENDANDTOWNSENDANDCREW,LLP
TWOEMBARCADEROCENTER,EIGHTHFLOOR
SANFRANCISCO
CA
94111-3834
US
Assignee:
SiliconGenesisCorporation
SanJose
CA
SerialNo.:
460899
SeriesCode:
12
Filed:
July23,2009
CurrentU.S.Class:
257/618;257/E21.215;257/E23.002;438/705
ClassatPublication:
257/618;438/705;257/E21.215;257/E23.002
InternationalClass:
H01L21/30620060101H01L021/306;H01L23/5820060101H01L023/58
Claims
1.Amethodoffabricatingathicknessofsiliconmaterial,themethodcomprising:
providingasiliconingotmaterialhavingasurfaceregion;introducingapluralityofparticleshavinganenergyofabout1-5MeVandgreaterthroughthesurfaceregiontoadepthtodefineacleaveregionandathicknessofdetachablematerialbetweenthecleaveregionandthesurfaceregion;processingthesiliconingotmaterialtofreethethicknessofdetachablematerialatavicinityofthecleaveregion;causingformationofafree-standingthicknessofmaterialcharacterizedbyacarrierlifetimeofabout10microsecondsandless,afirstthicknessrangingfromabout20micronstoabout150micronswithatotalthicknessvariationoflessthanaboutfivepercent;treatingthefree-standingthicknessofmaterialusingatleastanetchingprocess;andperformingathermal/passivationprocessonthefree-standingthicknessofmaterialtorecoverthecarrierlifetimetogreaterthanabout200microseconds.
2.Themethodofclaim1whereinthefree-standingthicknessofmaterialaftertheetchingprocessissubstantiallyfreefromsurfacedamage.
3.Themethodofclaim1whereinthefree-standingthicknessofmaterialafterthethermaltreatmentprocessissubstantiallyfreefromsub-surfacedamage.
4.Themethodofclaim1whereintheetchingprocessremovesabout5-10%ofthethicknessofmaterialfromafrontsurfaceofthefree-standingthicknessofmaterialandfromabacksurfaceofthefree-standingthicknessofmaterialtohaveasecondthicknessrangingfromabout16micronstoabout120microns.
5.Themethodofclaim4whereinthefree-standingthicknessofmaterialaftertheetchingprocessretainsthethicknessvariationsubstantiallythesameasthatbeforetheetchingprocess.
6.themethodofclaim4whereintheetchingprocessleadstoaRMSsurfaceroughnessbetweenabout100-300nm.
7.Themethodofclaim4whereintheetchingprocessdevelopsatextureoneitherthefrontsurfaceorthebacksurfacecharacterizedbyhigherlighttrappingcapability.
8.Themethodofclaim1whereinthethermal/passivationprocessischaracterizedbyatemperatureofabout400DegreesCelsiustoabout800DegreesCelsiusandusageofiodine/methanolsolution.
9.Themethodofclaim1whereinthefree-standingthicknessofmaterialischaracterizedbyastrengthofabout1to5GPafracturestressasmeasuredbyaringonring.
10.Themethodofclaim1whereintheetchingprocesscomprisesdippingthefree-standingthicknessofmaterialintoasolutionofHF,nitricandaceticacidforapredeterminedtimeandwithapredeterminedspeed.
11.Amethodoffabricatingathicknessofsiliconmaterialhavingatotalthicknessvariationoflessthanabout5%(changeinthickness/thickness),themethodcomprising:
providingasiliconingotmaterialhavingasurfaceregion;introducingapluralityofparticleshavinganenergyofabout1-5MeVthroughthesurfaceregiontoadepthtodefineacleaveregionandathicknessofdetachablematerialbetweenthecleaveregionandthesurfaceregion;processingthesiliconingotmaterialtofreethethicknessofdetachablematerialatavicinityofthecleaveregion;causingformationofafree-standingthicknessofmaterialcharacterizedbyacarrierlifetimeofabout10microsecondsandless,afirstthicknesssubstantiallyequaltothatofthethicknessofdetachablematerial;treatingthefree-standingthicknessofmaterialusingatleastanetchingprocess;performingathermal/passivationprocessonthefree-standingthicknessofmaterialtorecoverthecarrierlifetimetogreaterthanabout200microseconds;andwhereinthefree-standingthicknessofmaterialhasastrengthabout1GPaandgreaterinfracturestress.
12.Themethodofclaim11whereinthefree-standingthicknessofmaterialaftertheetchingprocessissubstantiallyfreefromsurfacedamage.
13.Themethodofclaim11whereinthefree-standingthicknessofmaterialafterthethermaltreatmentprocessissubstantiallyfreefromsub-surfacedamage.
14.Themethodofclaim11whereintheetchingprocessremovesabout5-10%ofthefirstthicknessofthefree-standingthicknessofmaterialtoprovideasecondthicknesswithatotalthicknessvariation.
15.Themethodofclaim14whereinthefirstthicknessrangesfromabout20micronstoabout150microns;thesecondthicknessrangesfromabout16micronstoabout120micron;thetotalthicknessvariationislessthan5%.
16.Themethodofclaim15whereintheetchingprocessleadstoaRMSsurfaceroughnessofabout1000nmandlessasmeasuredbyatomicforcemicroscopy(AFM).
17.Themethodofclaim11whereinthethermal/passivationprocessischaracterizedbyanannealingtemperatureofabout400DegreesCelsiustoabout800DegreesCelsiusandusageofiodine/methanolsolution.
18.Themethodofclaim11whereinthefree-standingthicknessofmaterialischaracterizedbyastrengthofabout1GPaandgreaterinfracturestressasmeasuredbyaring-on-ringtest.
19.Themethodofclaim11whereinthefree-standingthicknessofmaterialischaracterizedbyastrengthofabout5GPaandgreaterinfracturestressasmeasuredbyaring-on-ringtest.
20.Themethodofclaim11whereinthesiliconingotisPtypecharacterizedbyaresistivityofabout0.2to12Ohmcentimeter
21.Themethodofclaim11whereintheetchingprocesscomprisesdippingthefree-standingthicknessofmaterialinasolutionofHF,nitricandaceticacid.
22.Asiliconwaferhavingatotalthicknessvariationoflessthanabout5%(changeinthickness/thickness)comprising:
afree-standingthicknessofsiliconmaterialhavingathicknessrangingfromabout20micronstoabout150microns;afirstsurfaceregionoverlyingthefree-standingthicknessofsiliconmaterial;asecondsurfaceregionoverlyingthefree-standingthicknessofsiliconmaterial;atotalthicknessvariationoflessthanaboutfivepercentfromafirstsurfaceregionofthefree-standingthicknessofsiliconmaterialtoasecondsurfaceregionofthefree-standingthicknessofsiliconmaterial;acarrierlifetimetogreaterthanabout200microseconds;andastrengthofabout1GPaandgreaterinfracturestress.
23.Thesiliconwaferofclaim22whereinthefirstsurfaceregionhasaRMSsurfaceroughnessofabout1000nanometers.
24.Thesiliconwaferofclaim22whereinthesecondsurfaceregionhasaRMSsurfaceroughnessofabout1000nanometersandless.
25.Thesiliconwaferofclaim22furthercomprisingaresistivityofabout0.2to12Ohmcentimeter.
26.Thesiliconwaferofclaim22whereinthefree-standingthicknessofsiliconmaterialcomprisesasinglecrystalsilicon,apolycrystallinesilicon,orametallurgicalsilicon.
Description
CROSS-REFERENCETORELATEDAPPLICATION
[0001]TheinstantnonprovisionalpatentapplicationclaimsprioritytoU.S.provisionalpatentapplicationNo.61/093,248filedonAug.29,2009andincorporatedbyreferenceinitsentiretyhereinforallpurposes.
BACKGROUNDOFTHEINVENTION
[0002]Thepresentinventionrelatesgenerallytotechniqueincludingamethodandastructureforformingasolarcellstructureusinglayertransfertechniquesforphotovoltaicapplications.Butitwillberecognizedthattheinventionhasawiderrangeofapplicability;itcanalsobeappliedtoothertypesofapplicationssuchasforthree-dimensionalpackagingofintegratedsemiconductordevices,photonicdevices,piezoelectronicdevices,flatpaneldisplays,microelectromechanicalsystems("MEMS"),nano-technologystructures,sensors,actuators,integratedcircuits,biologicalandbiomedicaldevices,andthelike.
[0003]Fromthebeginningoftime,humanbeingshaverelieduponthe"sun"toderivealmostallusefulformsofenergy.Suchenergycomesfrompetro