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152Vol115,No1220094JOURNALOFFUNCTIONALMATERIALSANDDEVICESApr.,2009:1007-4252(2009)02-0193-04:2008-06-17;:2008-07-07:(:2002CB311903);(:KGCX2-SW-107):(1983-),,,(E-mail:huangjun0108@hotmail.com).AlGaN/GaNHEMT,,(,100029):AlGaN/GaNHEMT,C2H4,Cl2/Ar/C2H4,AlGaN,,,,:AlGaN/GaN;HEMT;;;C2H4:TN325:AOptimizationongate-recessedAlGaN/GaNHEMTwithlowdamageetchingtechniqueHUANGJun,WEIKe,LIUXin2yu(InstituteofMicroelectronics,ChineseAcademyofSciences,Beijingl00029,China)Abstract:AsystematicstudyoflowdamageetchingrecessedgateofAlGaN/GaNHEMTisperformedaddingalittlefluxofpassivatinggasC2H4totheCl2/Arinductivelycoupledplasma,andtheCl2/Ar/C2H4isoptimized.ThesurfacedamageanddegenerationofAlGaNareavoidandtheetchingresultantisremovedfromthesurfaceoftherecessedgate.TheSchottkycharacteristicsandgatecontrolabilityareim2provedandthelowdamageetchingrecessedgatetechniqueisachieved.Keywords:AlGaN/GaN;HEMT;recessedgate;lowdamageetching;C2H40,GaN,GaN(3.49eV),(106V/cm),(1.7W/cmK)GaN,,[1],GaNHEMT[2,3]AlGaN/GaNHEMT,,AlGaN,,[4,5],Cl2/ArGaN[6,7,8],GaN,,,,(,)AlGaN/GaNHEMT,Cl2/ArC2H4,,,,AlGaN/GaN,,1AlGaN/GaNHEMT1,,MOCVD,3mGaN,3nmAlGaN,22nmAl2GaN25nm,Al28%1620cm2/Vs1.1591013cm-2AlGaN/GaNHEMT:(1),Ti/Al/Ti/Au,6.210-7cm-2(2),N(3),Si3N4120nm(4)(5),Ni/AuCorial200IL(ICP),,AlGaN8nm1AlGaNFig.1StructureofGata-RecessedAlGaN/GaNHEMT1AlGaN/GaNHEMT,Cl2Ar,2C2H4;LF,RF(AFM),AlGaN/GaN,,0.8m,60m,22C2H4,C2H4,2#GaN(AZ5214),,(RFBias),C2H4C2H4C[9],,3#C2H4,,,1Table1Dataofetchingrecessedgate(sccm)Cl2ArC2H4LF(W)RF(W)(sec)1#40303005802#4030.83005403#4033300580491152Tabla2EtchresultsofdifferentconditionGaNRFBias1#22nm/min18.6nm/min1.1830.9V2#11nm/min8nm/min1.3750.2V3#000V3HallTable3ResultofHallmeasurementofsamplesbeforeandafteretching1#2#(cm-2)1.159E+138.984E+121.139E+13(cm2/Vs)162014001520(ohm/sq)333428362,AlGaN/GaN,3,,1#Al2GaN/GaN,22.5%,13.6%,28.6%2#C2H4,RFBias,1#,,1.72%6.17%,8171%AFMAlGaN,,2,XY,Z,1#2#,(RMS),4,AlGaN1.21nm,1#AlGaN3.66nm,5nm,2#AlGaN1.59nmC2H4CAlGaNGaCl2GaCl3[6,7],,,,Fig.2AFMphotograghsofsurfaceroughnessofsamples2AFM5912,:AlGaN/GaNHEMT4(500nm3500nm)Table4Surfaceroughnessofsamples(500nm3500nm)1#2#(RMS)/nm1.213.661.5933(a),(Vgs)-20V,2#(Igs)1#4,C2H4,,,[8],,3(b),2#1#,(Gm)(Vth)C2H4,,,Fig.3Schottkycharacteristicsandtransfercharacteristicsofsamples33AlGaN/GaNHEMTAlGaN/GaNHEMTC2H4,,,,,,,:[1]KhanMA,ShurMS,ChenQC,etal.Current/voltagecharacteristiccollapseinAlGaN/GaNheterostructureinsu2latedgatefieldeffecttransistorsathighdrainbias[J].E2lectronLctt,1994,30(15):2175-2176.[2]OkamotoY,AndoY,NakayamaT,etal.High-PowerRe2cessed-GateAlGaN/GaNHFETwithaField-ModulatingPlate[J].IEEETRANSACTIONSONELECTRONDEVICES,2004,51(12):2217-2219.[3]MoonJS,ShihchangWu,WongD,etal.Gate-RecessedAlGaN/GaNHEMTsforHigh-PerformanceMillimeter-WaveApplications[J].IEEEELECTRONDEVICELE2TTERS,200526(6):348-350.[4]WangWK,LinPC,LinCH,etal.Performanceen2hancementbyusingthen+-GaNcaplayerandgaterecesstechnologyontheAlGaN/GaNHEMTfabrication[J].IEEEElectronDeviceLett,2005,26(1):5-7.[5]ShenL,PalaciosT,PoblenzC,etal.UnpassivatedhighpowerdeeplyrecessedGaNHEMTswithfluorine-plasmasurfacetreatment[J].IEEEElectronDeviceLett,2006,27(4):214-216.[6]ShulRJ,McClellanGB,CasalnuovoSA,etal.Induc2tivelycoupledplasmaetchingofGaN[J].ApplPhysLett,1996,69(8):1119-1121.[7]KimHS,YeomGY,LeeJW,etal.AstudyofGaNetchmechanismsusinginductivelycoupledCl2/Arplasma[J].ThinSolidFilms,1999,341(2):180-182.[8]ChoBC,ImYH,HahnYB,etal.InductivelycoupledplasmaetchingofdopedGaNfilmswithCl2/Ardischarges[J].ElectrochemSoc,2000,147(10):3914-3916.[9]BaoJJ,ShiHL,LiuJJ,etal.MechanisticStudyofPlas2maDamageandCH4RecoveryofLowkDieletricSurface[A].InternationalInterconnectTechnologyConference,IEEE[C].2007,4-6June,2007:147-149.69115