TrenchMOS

IntroductiontoTrenchMOSJensSchnepelMultiMarketSemiconductorsBLGeneralApplications,PLDiscretes/ssMOSJune2009CONFIDENTIAL2BasicTrenchMOScellstructureSourceAIOxidePolygatePDRAINN++P+N-N+CONFIDENTIAL3TrenchMOSCellinoff-stateSourceAIOxidePolygatePDRAINN++P+N-N+0V0V+20VDepletionCONFIDENTIAL4TrenchMOSCellinon-stateSourceAIOxidePolygatePDRAINN++P+N-N+0V+10V+1VN++NchannelCONFIDENTIAL5TrenchMOSCellstructureSourceAIOxidePolygatePDRAINCurrentpathN++P+N-N+CONFIDENTIAL6DMOSCellstructurePDRAINSourceAlOxidePolygate=RESISTANCE=CURRENTPATHN++P+N-N+CONFIDENTIAL7PowerMOSStructuresVerticalcurrentflowCellularstructure(squares,hexagons,stripes)EarlydesignsusedDMOS–Simplerprocess–Planargates–Bothhorizontal+verticalcurrentflow–JFETlimittoscalingModerndesignsTrenchMOS–Verticalcurrentflow–Gateslieinnetworkoftrenches–Morescaleable–MorecomplexprocessCONFIDENTIAL8SingleMOSFETdie(layout)85%oftopsurfaceisthicksourcemetalSourcebondingisonactiveareaSurfacespreadingresistanceissignificantBondwireBondwireBondwireCONFIDENTIAL9SingleMOSFETdie(photo)CONFIDENTIAL10GenericDeviceLayoutSOT23&TO220SOT223[GENERICSOT223DEVICELAYOUT]COPPERHEADERSOURCEBONDWIRE(S)SILICONDIE/CHIPGATEBONDWIREGATEBONDPADPLATEDDRAINTABPLATEDLEADSGDSDTO220SOURCEBONDWIRECOPPERHEADERSILICONDIE/CHIP‘T’-POSTSGATEBONDWIREGATEBONDPADPLATEDLEADS[GENERICTO220DEVICELAYOUT]PLATEDDRAINTABCONFIDENTIAL11Edgetermination+edgeofcellareaCONFIDENTIAL12EdgeofcellareaPolygateintrenchnetworkiscontactedonlyattheedgeoftheactiveareaCONFIDENTIAL13TrenchMOSedgeterminationperipheralgatebusbarpoly(drainconnected)edgeofactiveareapolyfieldplatePotentialweakgateoxidepointsTrenchesCONFIDENTIAL14SinglecellandtrenchnetworkCellshapecanbehexagonal,squareorstripeTrenchnetworkSourcecontacttoeachcellCONFIDENTIAL15TrenchnetworkafteretchCONFIDENTIAL16TrenchtopaftertrenchetchCONFIDENTIAL17Trenchtopcorneraftersacox(1)CONFIDENTIAL18Trenchtopcorneraftersacox(2)CONFIDENTIAL19TrenchtopcornerafterpolydepositionCONFIDENTIAL20Edgetrenchafterpolyetch(sideview)CONFIDENTIAL21Edgetrenchafterpolyetch(topview)CONFIDENTIAL22Edgetrenchafterpolyetch(sideview)CONFIDENTIAL23TrenchMOSprocessflowstage3-afterAPimplantresistoxidep-bodyimplantAPimplantCONFIDENTIAL24TrenchMOSprocessflowstage5-aftertrenchetchresistoxidetrenchCONFIDENTIAL25TrenchMOSprocessflowstage8-afterpolydepositionCONFIDENTIAL26TrenchMOSprocessflowstage12-aftern+implantresistn+implantCONFIDENTIAL27TrenchMOSprocessflowstage20-afterCBmaskAluminiumPlasmanitrideCONFIDENTIAL28POWERMOSRDS(on)ContributionsRDS(on)=Rchip+RpackageRchip=Rco+RN+RCHANNEL+Racc+RJFET+Repi+RsubsRpackage=RAl+Rwire+RleadAsVdsincreases,RepidominatesRDS(on)AsVdsreduces,RCHANNELdominatesRDS(on)AsRCHANNELreduceswithnewtechnology,RpackageandRsubsbecomemoresignificant1010010001000010000010100100010000BVdss/VSpecres/mohmmm2TheoreticalDMOSTrenchCONFIDENTIAL29