lec3_the_crystal_structure_of_solids

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1、Lecture3Lecture3SemiconductorphysicsITheCrystalStructureofSolids1SemiconductormaterialsTypesofsolidsSlSpacelattiicesAtomiBicBondingImperfectionanddopinginSOLIDSImperfectionanddopinginSOLIDS2SemiconductorSemiconductorsdefinitionAgroupofmaterialshavingconductivitiesbetweenthoseof

2、metalsandinsulators.Semiconductorclassification---GroupIVelementalmaterialsSiGe---compoundmaterialsofgroupIIIandgroupIVelements.GaAs–commoncompoundsemiconductorforhigh-speedandopticaldivices.GaPInPFigPidiPeriodictable.---three-elementcompound3semiconductorl1IntrinsicsiliconVPur

3、esiliconcrystal•SiisinColumnIVoftheperiodictablewithatomicnumber14.•byfarthemostcommonsemiconductorusedinICs.4幻灯片4l1siliconisthemostcommonsemiconductorusedinICs.lixc,2013-3-3TYPESOFSOLIDSTYPESOFSOLIDSAccordingtothesizeofanorderedregionwithinthematerialtherearethreeAccordingtoth

4、esizeofanorderedregionwithinthematerial,therearethreetypesofsolids:(a)amorphous(b)polycrystalline()il(c)singlecrysttlal---thbtltilthebestelectricalpropertiesduetowithoutgrainboundaries.FigSchematicsofthreegeneraltypesofcrystals:FigSchematicsofthreegeneraltypesofcrystals:(a)amor

5、phous,(b)polycrystalline,(c)singlecrystal.5SPACELATTICESLatticeofthesinglecrystalLatticeofthesinglecrystal---theperiodicarrangementofatomsinthecrystal.Primitivecell/unitcellPrimitivecell/unitcell---thesmallestunitcellthatcanberepeatedtoformthelattice.FigTwo-dimensionalreppgrese

6、ntationofasingle-crystallatticeshowingvariouspossibleunitcells6aFigAgeneralizedprimitiveunitcell.latticepointlatticepoint---torepresentaparticularatomicarraybyadot.---itslocationexpressedusingthevectorddddrpaqbsc=++Wherep,q,andsarepositiveintegersarepositiveintegers.7BasicCryst

7、alStructuresa:latticeconstantFigureThreelatticetypes:(a)simplecubic.(()b)bodyy-centeredcubic.(c)face-centeredcubic.8Volumedensityofatoms¢VlVolumeddiensityoffatomsiidsdetermiidbnedby---thecrystalstructureofamaterial---itslatticedimensionsitslatticedimensionsExample:Considerasing

8、le-crystalmaterialthatisabody-centeredcubicwithalattic