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IEEETRANSACTIONSONDEVICEANDMATERIALSRELIABILITY,VOL.16,NO.1,MARCH201669

RobustTrenchBuried-Guard-Ring-Based

TerminationforChargeBalancedDevices

KarthikPadmanabhan,MadhurBobde,LingpengGuan,andJiann-ShiunYuan

Abstract—Amajorlimitationontheperformanceofhigh-

voltagepowersemiconductoristheedgeterminationofthedevice.

Itiscriticaltomaintainthebreakdownvoltageofthedevicewith-

outcompromisingthereliabilityofthedevicebycontrollingthe

surfaceelectricfierminationstructureiscriticaltothe

posedtermi-

nationusesanoveltrenchMOSwithburiedguardringstructure

tocompletelyeliminatehighsurfaceelectricfieldinthesilicon

posedterminationschemewas

appliedtowarda1350-Vfastrecoverydiodeandshowedexcellent

eved98%ofparallelplanebreakdownvoltage,with

lowleakageandnoshiftsafterhigh-temperaturereversebias

testingduetomobileioncontaminationfrompackagingmold

compound.

IndexTerms—Breakdown,buriedP-ring,chargebalance,edge

termination,fastrecoverydiode,IGBT,junctioncurvature,mo-

bileions,powerMOSFET,trench.

UCTIONHIGHvoltagepowersemiconductordevicesareusedin

ncludethehigh

voltagepowerMOSFETsinpower卜算子咏梅陆游拼音版 suppliesforFlyback,PFC

andLLCtopologies,insulatinggatebipolartransistors(IGBTs)

andfastrecoverdiodes(FRDs)formotordrives,induction

nlyusedtechniquefor

improvingtheperformanceofthesehighvoltagedevicesis

touseaP-typeguardringand/oratrenchMOSfieldplatein

lowsfortheincreaseindopingofthe

N-region,whichinturncanbeusedtolowertheonresistance

ofaMOSFET[1],injectionenhancementofanIGBT[2]and

injectioncontrolofaFRD[3].

Oneofthemajorchallengesinthedesignofthesehigh

poseofthe

terminationregionistoavoidprematureavalanchebreakdown

duetoelectricfieves

thisbyspreadingoutthedepletionregionatthedevicesurface

alsoresultsinhighsurfaceelectricfieldinthetermination

region,insiliconandthepassivationlayer.

Themostcommonlyusedterminationtechniquesincludethe

abruptparallelplanejunction[4],junctionterminationedge

ManuscriptreceivedApril20,2015;acceptedDecember21,

publicationJanuary6,2016;dateofcurrentversionMarch4,2016.

abhan,,ewithAlphaandOmegaSemi-

conductor,Sunnyvale,CA94085USA(e-mail:karthik.p@).

J.-withtheDepartmentofElectricalandComputerEngineering,

UniversityofCentralFlorida,Orlando,FL32816USA.

Colorversionsofoneormoreofthefiguresinthispaperareavailableonline

at.

DigitalObjectIdentifier10.1109/TDMR.2016.2515507

uildingblockoftheproposedterminationstructure.

(JTE)[5],fieldrings[6],planarjunction[7],metalplates[8],

sacomparativereviewoftheabovementioned

schemesalongwithafewothersin[9].Forasuperjunction

structure,theterminationschemesareasshownin[10]–[12].

Oneofthemajorlimitationsoftheseterminationtechniques

istheirhighsurfaceelectricfikesthese

terminationtechniquesmoresusceptibletomobilechargesdur-

hightemperature,highvoltagebias

burn-intests,mobileionsfrompackagingmoldcompoundand

outsidesourcescanaccumulateintheterminationregion

andalteritselectricfieldshape,whichcanincreaseleakage

andlowerbreakdownvoltage(BV)icon

regionismoresusceptiblecomparedtoSiO

2

andSi

3

N

4

films

becauseofmorethanorderofmagnitudelowercriticalelectric

fieldstrengthcomparedtothesepassivationfilms.

Theterminationstructureproposedhereeliminatesthehigh

electricfieldnearsiliconsurface,therebyprovidingamore

robuststructurewhichislesssusceptibletomobilecharges

duringreliabilitytesting,asmentionedin[13]and[14].Itfits

wellwiththechargebalancedstructurespresentedin[1]–[3],

butcanbealsobeusedforplanarandsuperjunctionstructures.

Thebasicbuildingblockusedintheproposedtermination

istsofadeeptrenchMOSstructure

withaflly

dopedP-typeregion,whichtypicallyformsthebodyregionin

theactivecell,ispresentthroughoutsurfaceofthetermination

lydopedN-typeregion,whichformspartof

thedriftregionintheactive,isalsopresentinthetermination

dopingconcentrationforthehigherdopedN-regionisaround

1530-4388aluseispermitted,butrepublication/redistributionrequiresIEEEpermission.

See/publications_standards/publications/rights/rmoreinformation.

70IEEETRANSACTIONSONDEVICEANDMATERIALSRELIABILITY,VOL.16,NO.1,MARCH2016

edterminationscheme.

1016cm

−3

,comparedtothedriftregionconcentrationof

81013cm

−3

.

TheN-regiontypicallyextendstoadepthof6mor

senceoftheheavilydopedN-regionmakesit

difficulttoimplementaconventionalfieldlimitingring(FLR)

structure,ormostoftheterminationschemesreferencedabove.

Thecompleteterminationstructureisimplementedbyusing

severalunitcellsshowninFig.1,withoptimizedspacing,

soimportanttonotethatthepoly

electrodeforeachoftheterminationunitcellsisstrappedtothe

suresthat

thepolysiliconelectrodepotentialgetsclampedtothesilicon

mesavoltageasthedepletionregionspreadsinthetermination

region.

Spacingbetweentheburiedguardringsdeterminesthevolt-

agedropbetweenadjacentmesas,asillustratedbytheelectric

rtoconventionalguardrings,

thespacingwillbelessforunitcellsclosertotheactiveregion

becauseofthehighverticalcomponentofelectricfi

gofartherandfartherawayfromtheactiveregion,thespacing

willincreasetoaccommodatehighervoltagedropbetween

r,thekeydifferenceinthistermination

techniqueisthattheelectricfieldtransitionfromsiliconinto

thetrenchlineroxidenearthesurfaceduetothepresenceof

kesthesilicon

mesaoftheterminationsurfacefieldfreewithallthepotential

droppinginthetrenchoxide.

Sincethebulkoftheelectricfieldissupportedinthetrench

lineroxide,thethicknessoftheoxideiscriticalindetermining

it

usuallycomesfromthecriticalelectricfieldinsiliconnearthe

portanttochooseaburiedguard

ringspacingthatdoesnotdropvoltagehigherthanwhatthe

unitcellcansupport.

Fig.3belowshowsthebreakupoftheelectricfieldcompo-

nentsalongasinglepolyfickerlineroxide

alsomakesthestructuremoreimmunetoanytrappedcharge.

Fig.3(b)showsthebreakdownoftheelectricfieldbetween

[A]signifiesthepeakelectric

fieldcomponenti古诗赠汪伦古诗 nthetrenchlineroxide,and[B]signifiesthe

electricfiionbe-

Fig.3.(a)Crosssectionofasinglepolysiliconfilledtrenchandtheburied

guardring,and(b)accompanyingelectricfield.

tweenthetrenchesiscoveredbytheP-baseimplant,sothe

onlywaythepotentiallinescanterminateisthroughthetrench

hepotentiallinesconvergeinthetrenchliner

oxide,thepeakelectricfieldoccursinthatregion.

Eventhoughtheoxidehasahighercriticalelectricfield

(1107V/cm),thesiliconjunctionbreakdownvoltageiswhat

determinestheoverallBVsinceithasthelowercriticalelectric

field(3105V/cm).Sothespacinghastobedesignedina

mannersoastonotexceedthatlimit.

TheotherfactorthatcontrolstheBVisthedoseoftheburied

erdopingoftheburiedP-ringwillensurea

lowerpinch-offvoltagewithlowelectricfieldatthetrench

erdopingoftheburied

P-layerwillcausehigherelectricfieldnearthetrenchbottom

duetodepletionoftheburiedP-layer,er

case,adjustmentofthemesawidths/guardringspacingcanbe

usedtooptimizethebreakdownvoltage.

Anotherinterestingaspectofthisterminationstructureisthe

creationofseveralPMOStransistorconnectedinseriesfrom

OStransistorconsistsofasource

formedbytheoutermesa,gatebythetrenchpolyanddrain

formedbytheinnermesa(closertotheactive).Ifthetrench

polyofaterminationcell(gateofthePMOS)isconnectedto

theinnermesa(PMOSdrain),theblockingvoltageofthatguard

ringmaybelimitedbyitsfieldthresholdvoltageifithappens

trenchpolyisconnectedtotheoutermesa(PMOSsource),the

blockingvoltageofthatguardringisdeterminedbyitspinch-

offvoltage.

Thedrainconnectedtrenchesareusefulintheinitialpartof

theterminationbecausethatistheareawhichseesmaximum

verticalcomponentoftheelectricfistofthe

electricfieldiscontrolled,thesourceconnectedtrencheshelp

transitiontherestoftheelectricfieldtothesurface.

PADMANABHANetal.:ROBUSTTRENCHBURIED-GUARD-RING-BASEDTERMINATION71

ownvoltageversusepiresistivityfordifferentp-doping

concentrations.

ownvoltageversustrenchdepthfordifferentp-ringdoping

concentrations.

Otherfactor兔组词 saffectingtheterminationbreakdownvoltage

venburiedP-ring

dose,theresistivitydeterminesthelateralspreadoftheP-ring,

controllingtheamountofpinch-offbetweenthetrenches,and

hence,.4showsthevariationof

BVfordifferentcombinationsoftheburiedP-ringanddrift

resistivityforagiventrenchdepthof6m.

Anotherimportantfactorthatimpactstheterminationdesign

vendriftresistivity(70-cm),

variationinBVfordifferentcombinationsoftheburiedP-ring

depthaffects

thechargebalanceofthedevice,sochangesinthetrenchdepth

wouldalterthenetchargebalancecombinedwiththeburied

akdownthresholdfor

thesourceconnectedtrenchismuchlower,sothespacinghas

tobeconservativeinitiallywhileincreasingoutwardtobalance

theremainingelectricfield.

Asdiscussedpreviously,asignificantadvantageofthister-

minationstructureoveratraditionalguardringstructureis

itsrobustnessagainstinfluenceofmobileionsduringhigh

hesiliconjunctioninterfacein

theproposedstructureoccursdeeperinthesilicon,thepresence

ofmobileionsinducesanegligibleshiftinthebreakdown

voltage.

entcharacteristicsoftheterminationschemeareshown.(a)full

terminationwithlocationofimpactionizationhotspotand(b)distributionof

theelectricfield.

InFig.6(a)aterminationdesignblocking1350Visshown

alongwiththelocationoftheimpactionizationhotspot.

Fig.6(b)showstheelectricfieldbothatthesurface,and

belowtheburiedguardring(BGR)ldbenoted

thattheactiveareaistotherightoftheterminationscheme

actionizationspotiswherethepeakelectric

fieldinsiliconoccurs,canbeobservedtobedeepinsidethe

kelectricfieldatthesurfaceoccursin

ticalE-fieldinsilicon

dioxide(1107V/cm)ishigherthanthecriticalE-fieldin

silicon(3105V/cm).ThemaximumE-fieldsobservedinthe

oxideandsiliconintheschemearebothwithintheacceptable

theoreticallimits.

Alloftheabovedataanddiscussionservetounderlinethe

impactofthisterminationschemeonthereliabilityofthe

.7showstwodifferentterminationstructures:

a)aregularplanarguardringtermination;andb)atrenchbased

structure.

Asshownabove,theguardringinFig.7(a)terminatesthe

electricpotentiallinesattheSiliconsurface,whilethetrenchin

Fig.7(b)

causesthepeakelectricfieldtoocc岛的组词 urattheedgeoftheguard

ringforaplanartermination,whichthepeakelectricfieldfor

thetrenchbasedstructureoccursintheoxide.

Fortheguardringstructure,sincethepeakelectricfieldlimit

insiliconis3105V/cm,thismakestheterminationmore

reliabilitytestingconditionslikehightemperaturereversebias

(HTRB),rast,thetrench

FRDsupportsmostoftheelectricfieldinthelineroxide,

whichhasmuchhigherthresholdforthepeakelectricfield

(1107V/cm).Thismakesitimmunetosurfacecharge,and

hencemorereliable.

Theimpactofparasiticchargeintheterminationisstudiedin

detailin[15].Theburiedguardringintheproposedstructureby

virtueofitspositionisprettyimmunetotheeffectsmentioned

in[15].Theimpactofsurfacechargeonthebreakdownvoltage

72IEEETRANSACTIONSONDEVICEANDMATERIALSRELIABILITY,VOL.16,NO.1,MARCH2016

isonoftheterminationschemesandtheshapeoftheelectric

potentiallinesfor(a)planarFLR,and(b)trenchstructure.

ownvoltageasafunctionoftrappedoxidecharge.

oftrenchbasedterminationandplanarFLRterminationhas

rmi-

nationschemeshaveawidthof∼370inFig.8the

breakdownvoltageofplanarFLRterminationdecreaseswhen

thetrappedchargeincreases,whilethebreakdownvoltageof

trenchbasedterminationisrelativelyinsensitivetotrapped

charge.

Fig.9showstheeffectofthetrappedchargeontheelectric

fielddistributioninthesiliconatthesurfaceintheproposed

chbasedterminationtheelectricfield

he

depthoftheburiedguardring,theeffectofthetrappedcharge

ctricfieldiswellbelowthecritical

fieldonsilicondioxide(1107V/cm).

oftrappedoxidechargeontheelectricfielddistributionlinesfor

theproposedtrenchbasedtermination.

oftrappedoxidechargeontheelectricfielddistributionlines

foraplanarFLRbasedtermination.

Fig.10showstheeffectofthetrappedelectricchargeon

theelectricfielddistributionatthesurfaceinaregularFLR

ninthis

figure,theeffectofthetrappedchargeismoresevereinthis

scenarioduetothepeaksiliconE-fieldoccurringatthesurface.

Thehigherinterfacechargeleadstothefieldrisingabove

3105V/cm,whichcausesadropinthebreakdownvoltage.

SANDDISCUSSION

Theproposedterminationstructurewasimplementedinsil-

iconfora1350VFRDandtheresultingbreakdownvoltage

esignthetrench

depthis6m,thetrenchwidthis2.5m,linearoxidethickness

is6700,thetotalepithicknessis120m,andthetotal

terminationwidthis380nga20%BVmargin,

weareabletoachieveabreakdownvoltageof1640Vagainst

alizesa

98%efficiencyforhighvoltagetermination.

TheHTRBreliabilitydataforplanarandtrenchbasedter-

minationsarecomparedafterhightemper宋朝皇帝顺序列表图 aturestress(150

◦

C)

s

inFigs.11and12,

theleakagecurrentincreasessignificantlyfortheplanartermi-

nationafterhightemperaturestress,whiletheleakagecurrent

doesnotchangemuchforthetrenchbasedterminationafter

PADMANABHANetal.:ROBUSTTRENCHBURIED-GUARD-RING-BASEDTERMINATION73

ecurrentreliabilitydataforplanartermination.

ecurrentreliabilitydatafortrenchbasedtermination.

posedterminationstructurealsopassedall

reliabilitytestsstressconditionsetbythelimitof10

−5

A,

whileafewdatapointsofplanarterminationjumpbeyond

10

−5

leakagecurrentismeasuredat1350V.

SION

Thisbriefshowsanovelterminationschemebasedona

trenchandaburiedp-ringtoimplementarobusttermination

rminationshowsgood

ruggednesswithregardstohightemperatureleakagecurrent

reliability.

Thepresentworkdealsonlywithahighvoltageratingof

1350V,buttheschemecanbeappliedforallvoltageratings

>lsoextendthisconcepttoafullsuperjunction

structurebyjustextendingthetopsideheavierN-regiondeeper

intothesiliconwhilesimultaneouslyaddingmoreP-ringsto

chargebalancetheN.

REFERENCES

[1]al.,“AnoveltrenchshieldedMOSFETwithburiedfieldring

fortunableswitchingandimprovedruggedness,”27th

ISPSD,Jun.2015,pp.401–404.

[2],,,,“TrenchShieldedPlanarGate

IGBT(TSPG-IGBT)forlowlossandrobustshort-circuitcapalibity,”in

25thISPSD,Jun.2013,pp.25–28.

[3]abhanetal.,“Anoveltrenchfastrecoverydiodewithinjection

control,”26thISPSD,Jun.2014,pp.23–26.

[4],k,NY,USA:Wiley,

1987.

[5],uki,a,“Analysisofajunctiontermi-

nationstructureforidealbreakdownvoltageinp−njunctiondevices,”

onDevices,-27,no.1,pp.261–265,Jan.1980.

[6],,,,“Theoryand

breakdownvoltageforplanardeviceswithasinglefieldlimitingring,”

onDevices,-24,no.2,pp.107–113,Feb.1977.

[7]s,“Avalanchebreakdownvoltagesofabruptand

linearlygradedp−njunctionsinGe,Si,GaAsandGaP,”.

Lett.,vol.8,pp.111–113,1966.

[8],ko,Jr.,,“Effectofsurfacefields

onthebreakdownvoltageofplanarsiliconp−njunctions,”IEEETrans.

ElectronDevices,-14,no.3,pp.157–162,Mar.1967.

[9],“Highvoltagedeviceterminationtechniquesacomparative

review,”.—Solid-StateElectronDevices,vol.129,

no.5,pp.173–179,Oct.1982.

[10]niec,,er,“Space-savingedge-termination

structuresforverticalchargecompensationdevices,”13th

EPE,2009,pp.1–10.

[11],,,,“Anovelcharge-imbalancetermi-

nationfortrenchsuperjunctionVDMOS,”IEEEElectronDeviceLett.,

vol.31,no.12,pp.1434–1436,Dec.2010.

[12],,,,“Deepoxidetrenchtermination

structureforsuper-junctionM中秋有关的诗词 OSFET,”.,vol.48,no.16,

pp.1018–1019,Aug.2012.

[13],,,“Terminationdesignforhighvoltage

device,”8680613,Mar.24,2014.

[14],“Improvedterminationdesignbymetal

strappingguardringtrenches,”2,Jun.11,

2015.

[15]vic,,,unga,“Theeffect

ofstaticanddynamicparasiticchargeintheterminationareaofhigh

voltagedevicesandpossiblesolutions,”.

sICs,2002,pp.263–266.

Authors’photographsandbiographiesnotavailableatthetimeofpublication.