纳米材料和纳米结构第七讲PPT文件格式下载.ppt

纳米材料和纳米结构第七讲PPT文件格式下载.ppt

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afewmTorrtoseveralhundredsmTorrwProcedureGenerationofpositiveions:

ionizingthesputteringgasbyglowdischargeBombarding:

acceleratedpositiveionstostrikethetargetsurfaceandremovemainlyneutralatomsCondensation:

neutralatomsleavethetargetandcondenseonthesubstratesurface,andformintothinfilmswAnImportantConcept:

SputteringYieldAmeasurementoftheefficiencyofsputteringRatioofthenumberofemittedparticlestothenumberofbombardingones1-2SputteringSystemwTypicalTypesofSputteringSystemsDirectcurrent（dc）diodesputteringUsedforsputteringconductingmaterialsRadiofrequency（rf）diodesputteringUsedforsputteringinsulatingmaterialsMagnetrondiodesputteringMostcommonlyusedtodayPlasmabeconfinedaroundthetargetsurfacebyamagnetfieldAdvantagesofusingmagnetronsputteringlFeasibilityoflargecathodesizelHighsputteringyieldlLessbombardmenttothesubstrate用于用于制备制备TiN/VN多多层膜层膜的磁的磁控溅控溅射系射系统统氩气氩气流量表流量表流量控制阀流量控制阀压力传感器压力传感器低温泵低温泵低温泵低温泵靶靶1靶靶2旋转衬底支架旋转衬底支架衬底衬底流量表流量表阀门阀门流量表流量表流量控制阀流量控制阀1流量控制阀流量控制阀2主流量控制阀主流量控制阀质谱仪质谱仪阀门阀门锁定装置锁定装置wWaystoreducethedamageandre-sputteringofgrowingfilmDamagecausedbynegativeioneffectandradiationenhanceddiffusionImprovementmethodUsehighgaspressure:

toreducetheenergyofthenegativeionsUseoff-axissputtering:

toavoidthesubstratedirectlyfacingthecathodeDisadvantageofoff-axissputtering:

llowdepositionratelsmalldepositionareawDepositionofmagneticmaterials:

facingtargetsputteringsystems偏轴溅射系统偏轴溅射系统示意图示意图Schematicofoff-axissputteringsystem可可360度旋转的衬底支架度旋转的衬底支架陶瓷加热器陶瓷加热器负离子撞击区负离子撞击区衬底衬底靶靶溅射枪溅射枪溅射源溅射源屏蔽闸屏蔽闸空间屏蔽区空间屏蔽区正面溅射系统正面溅射系统示意图示意图Schematicofthefacingtargetsputteringsystem衬底衬底靶靶磁体磁体冷却水冷却水氩气氩气1-3PreparingMultilayerStructuresbySputteringwTypesandPropertiesofMultilayerStructuresTypesofarchitecturesMetal/metalCeramic/ceramicMetal/ceramicSemiconductor/semiconductorStructuralandphysicalpropertiesWithstructurallymodulatedarchitecturesWithcompositionallymodulatedarchitecturesHighinterfacevolumefractionLargeintrinsicstressWithstructuraland/orcompositionalgradientExhibitinguniqueandenhancedelectric,dielectric,magnetic,andmechanicpropertieswBaTiO3NanolayerFerroelectricThinFilmCapacitorsAdvantage:

higherrelativedielectricconstantDisadvantage:

highleakagecurrentElectricalpropertiesstronglydependingupontheprocessingcondition,microcrystalstructure,andchoiceofbottomelectrodeAmorphous:

lowdielectricconstant（16at105V/cm）,lowleakagecurrentPolycrystalline:

highdielectricconstant（400at105V/cm）,highleakagecurrentAimofnanolayerstructureBaTiO3filmcapacitor:

highdielectricconstantandlowleakagecurrentRealizationandeffectsSubstrate:

Ru/SiO2/SiTechnique:

rfmagnetronsputtering,sputteringinterruptionbetweenlayerstochangethesubstratetemperatures（680CC,60CC）Layerstructure:

n-cyclealternatelayersofamorphousandpolycrystallineBaTiO3（microcrystallinebeobtainedbyannealingamorphouslayer）ResultsobtainedlLeakagecurrentdensitybeconsiderablyreduced,andtheeffectbecomingbetterwithincreasingcyclenumberlDielectricconstantbetwoorthreetimeshigherthansingleamorphouslayerbutlowerthanasinglepolycrystallinelayer具有纳米多层结构的具有纳米多层结构的BaTiO3薄膜电容器横截面示意图薄膜电容器横截面示意图wNanolayerMoSi2/SiCSubstrate:

singlecrystalsilicon（sc-Si）Techniques:

MagnetronsputteringfordepositionofMoSi2rfsputteringfordepositionofSiCMoSi2/Si