超高壓SiC功率(電力電子)器件

超高壓SiC功率(電力電子)器件超高壓SiC功率(電力電子)器件本次ICSCRM2011國際會議的最后一天，一個重要的討論內容集中在超高壓SiC功率(電力電子)器件方面。所謂超高壓器件是指電壓大于6500V的功率器件，其電流處理能力達到50A。目前傳統(tǒng)的Si基雙極型功率器件包括：IGBT、GTO、Thyristor、IGCT和ETO,這些器件面臨的主要問題是：(1)開關速度低,器件結溫低，(3)并聯(lián)性能差，(4)缺乏柵極控制能力，(5)重復恢復時間(tq)長，(6)額定電壓理論上限(~10kV)低，等，其具體電壓等級分別為：(1)Thyristor：9000V,(2)GTO：8000V,(3)IGBT：6500V， (4)MOSFET、SBD：~100-200V。高壓應用領域包括：(1)utilitygrid,(2)pulsedpower,(3)futureelectromagneticweapon,(4)protectionsystem,(5)veryhighvoltageswithesforHVDCpowertransmission,(6)windturbing,(7)powersustations,(8)Hightemperature。SiC功率半導體器件依其優(yōu)勢材料為基礎，可開發(fā)出與Si功率器件結構類似但突破Si基電壓極限的功率器件，如Thyristor、IGBT、GTO等，且具有正向電壓低、數(shù)KHz開關頻率、易于并聯(lián)的性質。該類器件的研發(fā)主要集中在美國研發(fā)單位或機構，如位于美國Virginia州的GeneSiC半導體公司、位于美國NC州的Cree公司、位于美國NY州的Silicon電力公司、位于美國MD州的NRL海軍研究實驗室、位于美國町州的Rutgers大學等。SiCThyristor 晶閘管器件 GeneSiC半導體公司0 1,0002.0003.0004,0005.000&0007.000ArKxk-CdthodEBiasW)<lual」no1.7kvSiliCOT (4)Losses■6kV^4konCarbideLosses3ge^s5-puaawaml-4kVSiThyristorS.3m￡]-Em;60.0Aino血-CathudEBias(V)(3)u>do占420 1,0002.0003.0004,0005.000&0007.000ArKxk-CdthodEBiasW)<lual」no1.7kvSiliCOT (4)Losses■6kV^4konCarbideLosses3ge^s5-puaawaml-4kVSiThyristorS.3m￡]-Em;60.0Aino血-CathudEBias(V)(3)u>do占42石AP」E蚩」念50.040.030.020.010.04.16 6.9 11 12 11.8LineVoltage(kV)圖片說明：（1）ComparisonofblockingvoltagesofGeneSiC'sSiCThyristorwitha4kVSiThyristor（2）On-stateI-Vcharacteristicsoflarge-area77mm2and28mm26.5kVSiCThyristors.（3） Comparisonof25°Con-statecharacteristicsofGeneSiC'sSiCThyristorwitha4kVSiThyristor.（4）On-statevoltagedropcomparisonbetweenSiliconandSiCbipolardevicesforvariousutilityvoltages.（3） 12kV1cm2SiCGTO晶閘——Cree公司TheSiCGTOofferssignificantadvantagesoveraSiGTOduetothelargebreakdownfieldandhightemperaturecapabilityofSiC.Thehighervoltageratingrequiresathickerdriftlayer.ThelowminoritylifetimecurrentlyinSiCnecessitatestheuseofminimumthicknessofthevoltageblockinglayer.Itisimportanttodevelopnewterminationstructurestomaximizetheblockingvoltageforagiventhicknessanddopingofthevoltageblockinglayer.Thisdevicewasbuiltonann+SiCsubstratewithap—typebufferlayerdopedat5X1016ic-3,2.5umthickandap-layerof90umthicknesswasgrownwithadopingof<2X1014ci-3.Followingthiswasthen-typebaselayer,dopedat~1X1017cm-3withthicknessof2.5um.12kVSiCGTOswithachipsizeof1cmX1cmandwithwidthof600iimnegativebevelterminationweredevelopedforthefirsttime,improvesthebreakdownvoltageby>3.5kVcomparedtotheconventionalmultiple-zoneJTEs.I■總*Negativehe\etrenmnationN?galirv?bowolZ?4$>02hiv/cmI■總*Negativehe\etrenmnationN?galirv?bowolZ?4$>02hiv/cm上左:Cross-sectionofaSiCGTOwithnegativebeveltermination.上右：Photographicimageofa1cmx1cmGTOchipwithnegativebeveltermination.下左：Electricalfieldcrowingattheedgeofthemesahasbeeneliminatedwithnegativebevel.termination.下右：BlockingIVcharacteristicsoftheSiCGTOwiththeconventional15-zoneJTEsandnegativebeveltermination.㈱732020BlockinfYiajdon11513DCClbwvftfGH0S91-11Driflthfckness:90uctttps-he:IcmXlcm㈱732020BlockinfYiajdon11513DCClbwvftfGH0S91-11Driflthfckness:90uctttps-he:IcmXlcm120 At7kV AtSkV At11Wbtvel左：Blockingvoltageyield(%)histogramswiththenegativebevel

terminationandconventional15-zoneJTEs.右：ForwardconductioncharacteristicsofthefabricatedSiCGTO.15kV4H-SiCIGBT——國Cree公司Duetothehighbreakdownfieldin4H-SiC,4H-SiCbipolardevicewillhaveanorderofmagnitudesmallerstoragechargeinthedriftlayer,ascomparedtothatofasiliconbipolardevicewithacomparableblockingvoltagerating.Significantlyeasiervoltagecontrolledversionsofthe4H-SiCswitch,suchasanIGBT,arestronglydesiredforadvancedapplicationstobeusedinfutureenergygridsystems.Forthispurpose,15kV4H-SiCIGBTwasdevelopedinCreebyutilizinga2x1014cm-3doped,140umthickp-typeepilayerasthedriftlayer,anda2umthickp-typeField-Stopbufferlayer,withadopingconcentrationrangingfrom1x1017cm-3to5x1017cm-3andmulti-zoneJTEedgeterminationstructureformedbynitrogenionimplantation.Thehighestblockingvoltageeverreported6.7mmx6.7mm4H-SiCP-IGBTwithanactiveareaof0.16cm2showedaleakagecurrentof0.6uAcorrespondingtoaleakagecurrentdensityof1.2uA/cm2ataVCEof-15kV.Thepulsedon-stateI-VcharacteristicsoftheP-IGBTwithanon-statecurrentof-145Arepresentingacurrent

densityof906A/cm2atVCEof-22.5VandaVGEof-20VwasmeasuredusingaTektronix371curvetracer.N-well N-welE140umr2xiOi4cm'5P~epifayer2 1^5xlO1?匚m5N-well N-welE140umr2xiOi4cm'5P~epifayer2 1^5xlO1?匚m5PbufferM+in矗ctor/substrate0 4 8 12 16 20collector0.711iii■ii0.0?I0.0 3.0k 6.0k9.0k 12.0k15.0k160. 0 5 10 15 20 25 30 35'%(V)6kV4H-SiCGTO——Rutgers大學SiChasahighbreakdownelectricfield,ahigh-saturationdriftvelocity,andahighthermalconductivity,idealforfast,high-powerswitchingdevices,includingSiCgate-turn-off(GTO)thyristors.A0.1cm24H-SiCGTOwith6kVblockingvoltagewasfabricatedonaasymmetricalNPNPstrueturewitha60—“mlightlydoped(N=9xl0i4cm—3)P—baseblockingAlayerfromCree,terminatedbyathree—zone,N—typejunctionTerminationExtension(JTE).UnlikeSiGTOs,theSiCGTOshavetheanodeonthetopandthecathodeonthebottom.TheforwardblockingcharacteristicsofGTOsweremeasuredbyusi