微專業---半導體制造技術課程：半導體工程專業英語ContentsSemiconductorProperties半導體特性01SemiconductorMaterials半導體材料02SemiconductorDeviceandHowTheyareUsed半導體器件及其使用03ProcessTechnology工藝技術04FabricationProcesses制造工藝05SemiconductorMaterialsandProcessCharacterization半導體材料與工藝表征06SemiconductorProperties1.1ElectricalConductivityofSolids1.2ElectricChargeCarriers1.3SemiconductorsandExternalInfluences1.4SemiconductorsinNanoscale011

SemiconductorProperties1ChapterOverview

Thegoalofthischapteristoconsiderinqualitativetermsfundamentalpropertiesofsolidsknownassemiconductors.Thediscussionisnotmeanttobeastructuredoverviewofthephysicsofsemiconductors,butratherasimplifiedreviewaimedattheidentificationofthosepropertiesofthisclassofmaterialswhichareessentialtotheunderstandingoftheprinciplesuponwhichfunctionalsemiconductordevicesarebuiltandoperate./?kwɑ?l?te?t?v/定性的/?s?mpl?fa?d/簡化的/s?mik?n?d?kt?rz/半導體器件2Introduction

Theextenttowhichasolidisabletoconductelectricityisacharacteristic

definingitsusefulnessintherangeofpracticalapplications.Inthissection

atomic-levelfeaturesdefiningelectricalconductivityofthesolidandatthe

sametimeareusedasacriteriaidentifyingaclassofmaterialsknownas

semiconductorsareconsidered./kra??t?ri?/標準1

SemiconductorProperties

1.1ElectricalConductivityofSolids/??tɑ?m?k

/原子的3Text

Electricalconductivityσ,whichisaninverseofresistivityρ(ρ=1/σ)and

whichisdeterminedbytheatomicstructureofmaterials,representsability

ofmaterialtoconductelectricity.

Electronsareplayingaroleofelectriccharge

carriersinthesolid.Themainfactorcontrollingelectricalconductivityσofthesolidisanumberofelectronswhich

arefree./??tɑ?m?k/原子的1

SemiconductorProperties

1.1ElectricalConductivityofSolids1.1.1

Interatomicbandsandelectricalconductivity/?k?ri?rz/載流子4(a)

Schematicdepictionofanatomusing

siliconwith4electronsinthe

outermostshellMasanexample.

/?ve?l?ns??lektrɑ?n/價電子/s??f??(?)nt/足夠的/?ba?nd??/束縛的1

SemiconductorProperties

1.1ElectricalConductivityofSolids1.1.1

Interatomicbandsandelectricalconductivity

(b)valenceelectronacquiresenergysufficientto

overcomebindingenergyandtobecomeafreeconductionelectron.5(a)

separated.

1

SemiconductorProperties

1.1ElectricalConductivityofSolids1.1.1

Interatomicbandsandelectricalconductivity

(b)broughttogetherandformingcovalent

bonds.

Siliconatoms

(c)electronreleasedfromthecovalentbondleavingbehindpositivelycharge

holewhichisfreetomoveandtocarrypositivecharge./?ko??ve?l?ntbɑ?nz/共價鍵61

SemiconductorProperties

1.1ElectricalConductivityofSolids1.1.1

Interatomicbandsandelectricalconductivity

Figure

(a)

showstwoseparatedfromeachothersiliconatomsschematicallyrepresentedbypositivelychargedatom

coresand

fourvalenceelectronsassociatedwiththeouter-mostatomicshell.When

broughttoclosecontactatomswillformabondusingtwovalenceelectrons,

onefromeachatomparticipatinginthebond(Fig

(b)).Abondcreated

thiswayisreferredtoasacovalentbond.Toformcovalentlybondedlattice

allfourvalenceelectronsofanatomareusedtoformbondswithfourneighboringatomsleavingnofreeelectrons.Ameasurableenergyisrequiredto

breakacovalentbondandtoreleaseanelectronmakingitavailableforconduction(Fig

(c)).Materialsfeaturingcovalentbondsarenotexpected

tobegoodconductorsofelectricityandassucharecommonlyreferredto

assemiconductors./?ve?l?ns??lektrɑ?nz/價電子71

SemiconductorProperties

1.1ElectricalConductivityofSolids1.1.1

Interatomicbandsandelectricalconductivity

Theresultoftheelectronbeingreleasedfromthecovalentbond(Fig

(c))isaleftbehind“hole”whichfeaturesthesameaselectron,

butpositiveelectriccharge.Similarlytotheelectron,theholecanmovein

semiconductorinthepresenceofelectricfield,andthus,canactasacarrier

ofthepositiveelectriccharge.

Siliconatoms電場81

SemiconductorProperties

1.1ElectricalConductivityofSolids1.1.2

Energybandstructureandelectricalconductivity

electricalconductivityofsolidsofinterestisthe

outermostsectionoftheenergybandstructureconsistingofvalencebands

andconductionbandsseparatedbytheenergygapasshowninFig

(a).

Theenergydifferencebetweenedgesoftheconduction(Ec)andvalence

(Ev)bandsisameasureoftheenergygapwidthEgalsoreferredtoasa

bandgapwidth.EnergybandText/k?n?d?k?nb?nd/導帶帶隙91

SemiconductorProperties

1.1ElectricalConductivityofSolids1.1.2

Energybandstructureandelectricalconductivity

Letusconsidernowsolidswhichfeaturevalencebandscompletelyfilled

withelectrons(Fig

(a)).Here,thevalenceelectronshavetoovercomethe

energygapinordertobecomeconductionelectrons.Otherwise,considering

completelyoccupiedvalencebands,no“tiedup”valenceelectroncancarry

electricalcurrent.Inconsequence,theenergyinexcessofEg,orinother

wordshighenoughtobreakinteratomicbondsandreleasevalenceelectrons,

hastobesuppliedtothesolidtomakeitelectricallyconductive.Following

thisreasoningthevalueofEgcanbeusedasameasuredefiningabilityof

varioussolidstocarryelectriccurrent.Dependingonthesolid,theenergygapwidthmayvaryfrom0eVformetals(Fig(b))toashighas10eVforinsulatorswhereelectronvolt(eV)isaunitofenergyuniversallyadoptedinsemiconductorterminology./?t??rm??nɑ?l?d?i/術語/??nt?r??tɑ?m?k/原子間的價帶10