1、等离子平板显示中冷阴极纳米金刚石膜的制备第 3l 卷第 1 期2008 年 2 月电子器件ChineseJourna1OfE1ectronDevicesVl0】.31No.1Feb.2OO8FabricationofNanocrystallineDiamondFilmforColdCathodeinPlasmaDisplayPanelszHUxtIeIfeng,WANGLin-jUn,HUGuang,LIUJian-rain,HUANGJian,XUJin-yong,xlAYiben(SchoolofMaterialsScienceandEngineering,ShanghaiUniversi
2、ty,Shanghai200072,China)Abstract:Thispaperdiscussesthefabricationofnano-crystallinediamondfilmsoflargeareaupto4cmX4cm.Usingelectronassisted-hotfilamentchemicalvapordeposition(EA-HFCVD)method,diamondfilmsweresynthesizedwithabiascurrentof6Aappliedforlh,followedwithnobiascurrentfor3hat0.8kPagaspressure
3、.Atomicforcemicroscopy(AFM)studyrevealedthediamondgrainsizeof30nm.ThreepointsrandomlyselectedonthesamplewerecharacterizedbyAFM.Goodcontinuityofdiamondfilmwasproven.Applyingellipsometerandspectrometer,wemeasuredtherefractiveindexandtransmittanceofprepareddiamondfilm.Goodqualitywasprovenwithatransmitt
4、anceabove50intheinfraredrange.DefinedHandO-surfacaterminationofdiamondfilmswereachievedrespectively.Usingcertainmethodology,wefoundouttheH-terminateddiamondfilmsoutperformedO-terminateddiamondfilmswitharound0.45.Keywords:nano-crystallinediamondfilm;high;transmittance;EAHFCVDECC:7260等离子平板显示中冷阴极纳米金刚石膜
5、的制备祝雪丰,王林军,胡广,刘建敏,黄建,徐金勇,夏义本(上海大学,材料科学与工程,上海 200072)*摘要:讨论大面积 4cmX4cm 纳米金刚石膜制备工艺.采用电子辅助一热丝化学气相沉积法(EA-HFCVD)在硅片上沉积纳米金刚石膜.生长过程中,预先加 6 安培偏流生长 1 小时,然后在 0.8 千帕条件下,无偏流生长 3 小时.原子力镜表征晶粒尺寸为 30 纳米.样品上任意三点采用原子力镜表征,表现出良好均匀性.采用偏振光椭圆率测量仪和分光计分别表征样品的折射率和透射率.红外波段透过率超过 50.金刚石膜表面分别进行氢化和氧化处理.通过表征,氢化处理后膜比氧化处理后膜对应的值大,约为
6、0.45.关键词:纳米金刚石膜;高 7;透过率;电子辅助一热丝化学气相沉积法(EA-HFCVD)中图分类号:TN873.94 文献标识码:A 文章编号:1o05949O(2OO8)O1 钮 O72-o5Nowadays,theplasmadisplaypanels(PDPs)whichiSbasedonhighfrequencydielectricbarrierdischargesarewidelyusedinthelargeareadisplayE.AnillustrationofthecrosssectionofaPDPdischargecelliSshowninFigure1.Asisd
7、epictedinFigurel,averythindielectriclayer,conventionallyaround1000nmofe-beamevaporatedMgO,isappliedtoprotecttheglassfromsputteringdamage,andevenmoreimportantlY.emitsasmanyelectronsaspossiblewheninterplayingwiththeionscreatedinthedischargegasSOastoletandkeeptheplasmastableatlowvolta-ges.Thedefinition
8、ofion-inducedsecondaryelectronemissioncoefficientiSformulatedasfollOWS.WhereNeiSdefinedasthenumberofelectronsemittedfromthedielectriclayerandNiiSde 一收稿日期:2007-0430基金项目:SupportedbythetheNationalNaturalScienceFoundationofChina(60577040),ShanghaiFoundationofAppliedMaterialsResearchandDevelopment(0404),
9、Nano-teehnologyprojectofShanghai(0452nm051,0552nm046)andShanghaiLeadingAcademicDisciplines(Tol01).作者简介:祝雪丰(1983 一),男,硕士生,现从事金刚石薄膜生长和金刚石薄膜探测器的研究.第 1 期祝雪丰,王林军等:等离子平板显示中冷阴极纳米金刚石膜的制备 73finedasthenumberofionsinteractingwiththesurface.Fig.1ThecrosssectionofaPDPdischargecellry 一(1)iRecently,moreandmorerese
10、archesrevealthat,althoughMgOisprevailinglyusedasthehigh“/-coatinginPDPcells.diamondpossessesmorepotentialduetoitsmarvelousfeaturessuchasnegativeelectronaffinity(NEA),largebandgap,lowsputteryieldanditshighestradiationhardness2I.Whatismore,diamondisthebestcandidatetostudytheroleoftheelectronaffinityXo
11、nioninducedemission.Astodiamondfilms,Nano-crystallinediamondfilmoutperformsmicro-crystallinediamondfilmduetoitshightransparence,whichisveryassentialintheperformanceofPDPs.Moreover,nano-crystallinediamondfilmpossessesnearlyallthemarvelousfeaturesoftypicaldiamondmateria1.Manystudiesconcerningtheapplic
12、ationofpoly-crystallinediamondfilmonPDPswereperformedbysomeresearchgroupspreviously,whiletheapplicationofnanocrystallinediamondfilmonPDPshasrarelybeenstudiedtillnow.Inthispaper,wedepositednano-crystallinediamondfilmonthepretreatedsiliconwaferbyelectronassisted-hotfilamentchemicalvapordeposition(EA-H
13、FCVD)method.Utilizingvariousempiricalcharacterizations,weprovethenano-crystallinediamondfilmofhighqualityandmuchpotentialintheapplicationofPDPs.1ExperimentalDetailsFrompreviouscontemplationandmanypreliminarytrials.wefoundoutthatnano-crystallinediamondfilmsdepositedviaelectronassisted-hotfilamentchem
14、icalvapordeposition(EAHFCVD)withcertaingrowthparameters,outperformedothersdepositedwithdifferentsyntheticparameters.Beforethedepositionofdiamondfilm,thesiliconsubstratewasscratchedwithdiamondpowderwithagrainsizeof100nm引 .Then,itwasrinsedinde-ionizedwatertogetofftheresidualdiamondpowders.Afterthat,it
15、wasetchedandpassivatedin45hydrofluoricacidforaround1minutetoremovethedioxidesilicononthesurface.Finally,itwasultrasonicallycleansedintheacetonebathforapproximately15minutesbeforetransferredintothereactor.ThedepositingconditionofthediamondfilmisillustratedindetailsinTable1.Thepre-treat-mentstepwasman
16、ipulatedwithinthepurehydrogenatmosphere.Afterthetemperatureofsubstratereached773K,thevalveofAcetone+H2pipelinewasturnedonandthenadjustedtoarooderatedegreetomakesurethattheAcetone/H2ratiowasbeneficialtotheformationofa13-SICcon-versionlayer引.Afterwards,keptonheatingthesubstratetillitstemperaturereache
17、saround873Kandthenappliedadecentbiasvoltagetothesubstratewithabiascurrentof6Aforaround1h.andfinallyturnedoffthebiasvoltagetogrowforabout3h.TableIThedepositingconditionofthepreparedsampleParameterPretreatmentNucleationGrowthTheRamanscatteringmeasurementswerecarriedoutatroomtemperatureusingJobinYvonIa
18、bRAMHRRamanspectrometer.Thesamplewasexcitedwiththe514.5nmlineofanArgon-ionlaserandtheRamanspectrumwastakenatthere-gion10001800cm 一.Atomicforcemicroscopy(AFM)wasperformedonAP_0190AFMwithScanMasterclosed_circuitscanningsystem.Scanningelectronmicroscopy(SEM)wasperformedonFEISIRION200.Refractiveindexoft
19、hepreparedsamplewasstudiedviaJobinYyonNV1SEI/460-VIAGASellipsometer.whilethetransnfittanceofthesamplewasmeasuredbyUV-365UVVLspectrometer.2ResultsandDiscussionThecharacterizationofSEMisshowninFig.2.AsshowninFig.2,thegrainsizeoftheasgrownfilm74 电子器件第 31 卷isnarsimwithallthegrainsevenlydistributedonthes
20、ubstrate.SomeblackdotsinFi 落 2aresupposedt0hetheresidualamorphouscarbonwhichcanbere-movedbyhydrogenetchingtreatmenLRamanscatter-ingmeasurenlentisshowninFi 落 3.Thecharacteristicbandofdiamondphaseiscenteredat1327cm-whichsthattheas-grownfilmisundermuchstre88.1【1bandseatedat1564cm-iscausedbygraphitethei
21、ntensityofgraphitebandwiththatofdiamondband,wefoundoutthattheconcen-tmtionofdiamondphasewaSnrethan95.Thecharacteristicbandcenteredat1155era-,Il 阻 sreportedtohecau.qJedbytrans-polyacetylene(trans-(CH)whichwascloselyconnectedwiththesizediamond.Fig.2TheSEMoftheas-grownfilm1000I20oI400l60oI800?I20oI400l
22、600Ranmshill/ra-JFig.3TheSalnllnspectrumoftheas-grownfilmThecharacterizationsofthreerandomlycho-senpointsontheas-grownfilmwereconductedthroughAFMasshowninFigure4.Goodcontinuitywasprovenindirectlyfromthedataandthegrainsizeofas-grownfilmwasmeasuredtohe30nminthecenter.Therootmean-square(rms)surfaceroug
23、hnessofthecenterwasmeasuredtobearound9nm,whilethemlssurfaceroughnessofsitebandsitecwasmeasuredt0bearound20nm.AsisshowninFigure4,smal1protuberancesr 口 po 暑阳 pn3lMTopography,12318000jlgl(a)Topography.12318000chd(b)l20(c)Fig.4TheAFMimagestakenonthreerandomlychosensites(a,b,c)onas-grownfilm(a)thecenterp
24、art;(b)lefttothecenterapartwith1cm;(c)righttothecenterapartwithlemareindeedexistedintheas-grownfilmduetothesecondarynucleationwhichcanbeattributedtotheeffectsoflowgaspressureandbiasenhancednu-cleation(BEN).Rigidlydesignedempiricalstepsareessentia1tothereproducibi1ityandqualityofdiamondfilms.Thechara
25、cterizationofioninducedemissionrevealsthatsmallprotuberancescanimprovetheelectronemissiontoacertaindegree,whichisveryimportantintheapplicationofPDPs.Thenucleationofdiamondfilmsis1argelydependentonthesubstratematerialaswellasthesurfacepretreatment.Thenucleationonsiliconwaferwithoutpretreatmentisquite
26、toughduetothehighsurfaceenergy(approximately6J/cmz)andlowstickingcoefficient.Implementingade-centbiasvoltage,thesurfaceenergyofthesubstrateiseffectivelyreduced,whilethepositivecarbon-containedspeciesarebombardingthesurfacewithgreatpower,whichisconducivetothenucle-眦啪鲫枷抛.IrB/参_至 IIl第 1 期祝雪丰,ag-g 等:等离子
27、平板显示中冷阴极纳米金刚石膜的制备 75ationE73.Withthecarbonicatomsincreasing,diffusingandmigratingonthesubstrate,theirenergiesareexchangedwiththesubstrate,andmainlyphysicallyadsorbedonthesubstrate.Thenthephysicallyadsorbedatomsgainsomeenergyfromthesubstrateandreactwithit,andfinallychemicallyadsorbedonthesubstrate.Wi
28、thcarbonicatomscontinuouslydepositedonthesubstrate,stableclusterscomeintobeing.Someformerresearchesrevealedthatthegaspressureinthereactoralsohadaverystrongimpactonthetopologyandstructureoftheas-grownfilms8:.Whenthegaspressureinthereactorisrelativelyhigh,thefreepathofactivatedhydrogenatomandcarbon-co
29、ntainedspeciesisaccordinglyshort,whichisdeleterioustotheprocessofseeondarynucleation.Asaresult,thegrainsofdiamondfilmareinclinedtogrowandlosethenano-size.Whenthegaspressureinthereactorbecomesrelativelylow,thetemperatureofsubstrateisinducedtorise.whichbringsonalargerdecompositionyield.Meanwhile,thefr
30、eepathofallparticlesinthereactoriselongated,bothofwhichcanacceleratetheparticlesintoahigherenergeticstatewheninteractingwiththesubstrate.Duringtheinteraction,theenergygainedbyparticlesistransferredtothesurfaceofthesubstrate,enhancingtheactivityofadsorbedparticles,whichcaneventuallyspeedtheformationo
31、fcarboncluster.Asaresult,thesecondarynucleationismanifestlyimproved.Furthermore,withastrongcollisionbetweentheactivatedparticlesandthesubstrate,thegrowthofgrainsisprevalentlyinhibited,whichcanimprovethesecondarynucleationindirectly.TherefractiveindexofthepreparedsampleisshowninFigure5.Therangeoftherefractivein-dexis2.22to2.23withtheincidentphotonenergychangingfrom0.8eVto1.4eV.Comparingitwiththerefractiveindexofnaturaldiamondwhichisaround2.5,wecanensurethatthediamond
