WCuW合金薄膜的矿床及其结构毕业论文外文文献翻译及原文.docx

WCuW合金薄膜的矿床及其结构毕业论文外文文献翻译及原文.docx

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WCuW合金薄膜的矿床及其结构毕业论文外文文献翻译及原文

毕业设计（论文）

外文文献翻译

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溅射磁控管W-Cu-W合金薄膜的矿床及其结构

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翻译日期：

2017.02.14

DepositionandstructureofW–Cu

multilayercoatingsbymagnetron

sputtering

CWang1,4,PBrault1,5,CZaepffel1,JThiault1,APineau2and

TSauvage3

1GroupedeRecherchessurl’Energ´etiquedesMilieuxIonis´es,UMR6606CNRS-Universit´e

d’Orl´eansBP6744,45067Orl´eansCedex2,France

2CentredeRecherchessurlaMati`ereDivis´ee,1BruedelaF´erollerie,F-45071Orl´eans

Cedex2,France

3Centred’EtudesetdeRecherchesparIrradiation,UPR33CNRS,3AAvenuedela

RechercheScientifique,45071Orl´eansCedex2,France

E-mail:

Pascal.Brault@univ-orleans.fr

Received22July2003

Published15October2003

Onlineatstacks.iop.org/JPhysD/36/2709

Abstract

W–Cu–WmultilayermetalliccoatingsaredesignedanddepositedbydcmagnetronsputteringonanFesubstrate.Correlationsbetweenthedepositionparameters,suchastargetpowerandArgaspressure,andthefilmcharacteristicsareinvestigated.Especially,depositionparametersforadenseW–Cumultilayercoatingarediscussed.Thecoatingsexhibitsmallgrainsizesandadensesurfacestructureforhightargetpowerandlowargonpressure,leadingtodenseandwelladhesivefilms.

1.Introduction

Tungsten,asahigh-atomicnumber（high-Z）andrefractorymaterial,hasattractedconsiderableinterestforitspotentialuseintheITERplasma-facingcomponentsandinmicroelectronictechnologyduetoitsexcellentthermalandelectricalproperties[1–3].Inaddition,tungsten-basedcoatingshavebeendevelopedforapplicationsinthefieldofwearorerosion-resistantcomponentsinhigh-temperature/highvacuumenvironments,forexampleW–C,W–Si,W–N,W–Re,W–La2O3[4–7].Ontheotherhand,duetotheveryhighthermalconductivityandfracturetoughness,Cuanditsalloyshavebeenwidelyusedasheatsinksinhigh-heatfluxplasmafacingcomponents.SoW–Cubecomesanattractivecandidatematerialforheatsinksinplasmaexperimentsaswellasarmour[4,8,9].Becausethereis（almost）nomutualsolidsolubility,onlyW–Cupseudo-alloys,asacompositematerial,areproduced.Fromaresearchpointofview,howtoobtainadensestructureandhowtoovercomethebigmismatchofthermalexpansionremainopenquestions.Finegrainsandcompositionally/functionallygradeddesignhavebeendiscussed[4,10,11]asanalternativeroute.However,W–Cucoatingshavemostlybeenfabricatedbymechanicalalloyingoftheirpowdermixtures[12,13].SofartherehavebeenfewstudiesreportedonaW–Cumultilayercoatingbyphysicalvapourdeposition（PVD）.Itiswell-knownthat,inPVDtechnology,thephysicalpropertiesofsputteredtungstenorcopperfilmsdependstronglyonthedepositionparameters,especiallythosecontrollingthekineticenergyofdepositingspecies.Forexample,Hubleretal[14]claimedthatthekineticenergymustbecontrolledinthe（best）energyrangeof5–30eVperatom.From0.1to10eV,thefilmgrowthmechanismchangesfromanisland-growthmodetowardsalayer-by-layermode,andbelowabout5eV,theenergyisineffectiveforchangingthephysicalprocess.Aboveabout30eV,defectsareintroducedintothefilmbydisplacementdamage.Thedepositionfluxandtheenergyoftheatomsandionsonthesubstratedeterminethedepositionrateandthefilmcharacteristics,respectively[15,16].Furthermore,thefluxandenergyaremainlycontrolledbythedepositionvariables:

targetpower（involvingvoltageandcurrent）,workingpressure（involvinggasspeciesandmassflow）,substratetemperature,substratebiasvoltage,target-to-substratedistance（dT–S）.Inthispaper,W–CumultilayerfilmshavebeendepositedontoanFesubstrateatroomtemperaturebydcmagnetronsputtering.Themostimportantdepositionparameters,targetpowerincludingtargetcurrentandvoltage,andArgaspressure,wereinvestigatedinordertoelucidatehowthedepositionparametersaffectthefilmcharacteristics（density,structure）andthephysicalproperties（adhesion）.Goodadhesionanddensestructurearepreliminaryrequirementsforthermalstabilityandgoodbehaviourunderplasmaconditions

2.Experiments

Amagnetronsputteringdepositionsystem（APRIMVIDE）,withthreeindependentlybiaseddcplanarmagnetrontargets,isusedtosputterWandCu（onetargetisidle）.Theresultingplasmasarewellconfinedabovethetargets.ThetargetdiscsofpureW（99.99%）andpureCu（99.99%）haveadiameterof10cmandathicknessof0.6cm,respectively.Thethreetargetsurfacesare30°tiltedfromthesubstratesurfacedirection,andthetargetsurfacecentreismadetofacethehalfradiusofthesubstrate,asshowninfigure1.Thedistancefromthetargetcentretothesubstratehalfradiusis9.0cm.Thesubstrateshave10cm×10cmsurfaceareaandarevacuumtransferredonarotatingholder.Thebasevacuuminthedepositionchamberisbetterthan1×10−7Pausingaturbomolecularpump（ATP900,ALCATEL）.Acoldcathode/piranigauge（ACC1009,ALCATEL）isusedtomeasurethevacuumintherangeof10−7–105Pa.Theworkinggasisargonanditisintroducedintothevacuumchamberatafixedflowrateof30standardcubiccentimetresperminute（sccm）.ThesubstratesarepureFe（200μmthick）andgreaseisultrasonicallyremovedusingacetonebeforemountingonthesubstrateholder.Priortoanydeposition,thetargetsurfaceissputter-cleanedfor3–5minwhilethesubstrateisprotectedbyamovableshield.Thedepositioniscarriedoutatroomtemperaturewithoutextraheatingorcoolingofthesubstrate.Thus,theeffectivesubstratetemperaturedependsonthedepositionconditions.Thetargetpowerischangedfrom100to650Wusingpowersuppliesofconstantpowertype.TheArgaspressureisvariedfrom0.2to2.5Pabycontrollingthepumpingspeed（throttling）andkeepingthegasflowrateconstant.ThedepositiontimeischosenaccordingtothedesiredcoatingthicknessofW（400nm）andCu（200nm）.Thecross-section,filmthickness,andsurfacemorphologyincludingthegrainsizearemeasuredbyscanningelectronmicroscopy（SEM）（Hitachi:

S-4200）.Thedepositionratesareestimatedfromthemeanthicknessmeasurementstakenfromcross-sectionalSEMmicrographs

Figure1.Schematicdrawingofthegeometricalpositionofthetargetandthesubstrate.

withknowndepositiontime.Thecrystallinestructureismeasuredbyx-raydiffraction（XRD）.ThesurfacearealdensityandthelayerdepthprofilearedeterminedbyRutherfordbackscatteringspectroscopy（RBS）usinga2.0MeV4He+ionbeamofaVandeGraaffaccelerator.

3.Resultsanddiscussion

ThesampleswiththelayeredstructureW（400nm）–Cu（200nm）–W（400nm）weredepositedonFesubstrateswithvariabletargetpowersandworkingpressures.Inordertoinvestigatetheeffectsofthetargetpoweronthefilmcharacteristics,thepowerwaschangedfrom200to650Wfortungstenandfrom100to300Wforcopperwhilekeepingtheworkingpressureconstantat1.0Pa.Figure2displaystheevolutionofthetargetbiasvoltage,V,andcurrent,I,asafunctionoftheinputpower.Withthesamepower,theelectriccurrentsattheWtargetarealwayslargerthantheCutarget,andconversely,WtargetbiasvoltagesaresmallerthanCutargetbiasvoltages.Figure3indicatesthatthedepositionratesofbothWandCuincreaselinearlywithincreasingtargetpowerforaconstantgaspressureof1.0Pa.Fortargetpowersfixedat500Wfortungstenand250Wforcopper,theArpressureischangedfrom0.2to2.5Pa.Thus,figure4displaysthevolutionofthetargetbiasvoltage,V,andcurrent,IagainstArpressure.ThedifferenceindepositionratesbetweenWandCuincreasesveryfastwithincreasingpressureabove1Pa,asshowninfigure5.AmaximumdepositionrateforWandCuisreachedwhenincreasingworkingpressureatfixedtargetpowers.Fromfigure5,themaximumdepositionrateofWis1.3nms−1,withatargetpowerof500W,whentheArgaspressureis2.0Pa.ThemaximumdepositionrateofCuis1.0nms−1,withatargetpowerof250W,whentheArgaspressureis1.0Pa.Beyondthismaximum,deposition

Figure2.VariationofthetargetvoltageandcurrentwithtargetpowerforWandCusputtering（Arpressure:

1.0Pa）

Figure3.VariationofthedepositionrateofWandCuwithtargetpower（Arpressure:

1.0Pa）

Figure4.VariationofthetargetvoltageandcurrentforWandCusputteringwiththeArgaspressureatafixedtargetpower（tungsten:

500W;copper:

250W）.

rateswilldecrease.Thisbehaviourresultsfromthemonotonicdecreasingtargetbiasvoltagewhiletargetcurrentcontinuouslyincreasesaspressureincreases（figure4）.Thismeansthatwhilemorepositiveionsimpingeonthetarget,lessmetallicatomsandionsreachthesubstrateduetothelowerbiasvoltageleadingtolessefficientsputtering.Moreover,theexcessArgaspressureinducesashortermeanfreepathofAr+ionswithmorefrequentcollisions,whichinducesalowerkineticenergywhentheyimpingeonthetarget.Asaresult,itcontributestolesssputteredatoms.Atahighworkingpressure,thesputteredmetallicatomsalsohavemorecollisionsandcanbescatteredoff,whichalsoaccountsforaloweringofthedepositionrate.

Figure6showsacross-sectionalviewoftheW–Cu–Wcoatinggrownatapowerof500W（fortungsten）and250W

Figure5.CorrelationofthedepositionratesofWandCuwithArgaspressureatafixedtargetpower（tungsten:

500W;copper:

250W）

.

Figure6.TheSEMphotographofacross-sectionstructureofaW–Cu–Wmultilayercoating（targetpower:

W,500W;Cu,250W;pressure:

1.0Pa）.

Figure7.ComparisonofSEMphotographsofWsurfacemor