Laser ablation sampling near the breakdown threshold

174 Pages·2000·1.7 MB·English

by  Potts, Gretchen E.

LASERABLATIONSAMPLINGNEARTHEBREAKDOWNTHRESHOLD
By
GRETCHENE.POTTS
OAFDTIHSESOUEFNRITTVAHETERISORINEDTQPYOURCIOETRFSOEEFRMNLETOONEFRTDIPSDTHAFOIOLITRNOHSPTEOAHGPREHRTDYIAEADLGURFAEUTELEFOSIFCLLHMOEONLT
UNIVERSITYOFFLORIDA
Copyright2000
GrcichcnE,Polls
Tomyfamily
ACKNOWLEDGMENTS
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beingamember.
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Gomushkin,Dr.BryanCastle.Dr.RicardoAucelio.HosseinNasajpour.ShaneClaggett.
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Croslyn.Dr.WendyClevengerCory.JasonKeeton.Dr.LeslieKingandJasonWallace.
1wouldalsoliketothankDr.GiuseppePctrucciforhisguidanceinthe"bigjobsearch.”
JeanneKnrablyisknownosibe“glue"ofIheanalyticalchemistrydivision,i
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intimesMoyfffraumsitrlaytihoans.providedcontinuoussupportthroughoutmygraduatecareer.
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TABLEOFCONTENTS
STID\mRISONANC1IMSSIONI
LBIISOTGORFAPRHEIFCEARLENSCKEETSCH., 157
LASERABALboRsAfetTtrqhaIueciOtUrNnoeifmvSeeDnAritssMssiPetfryLotroaItftNihFoGelnoDNPreriEgderaAseeiRnentoTPefadHrDtEtiooacBltthoFReurEGlofrAfialKdPluhmDaietOlnteoWsSooNcfphthTohyoHelRESHOLD
GrcAtucghucsntE2.0P0o0tts
Chairman:Dr.JamesD.Winefordner
aspectroscopy(LIPS)isanewanalyticalmethodfor
materialscharacterisationwhichusesthelaserasthesamplingandtheexcitationsource.
InLIPS,ashort-pulsedlaseristightlyfocusedontoasamplesurface.Duringthepulseof
thelaser,thesurfaceishealedbeyondthelatentheatofvaporisationandmaterialis
ablated.Thevaporisedmaterialdevelopsintoahotplasmaofhighelectronnumber
density.Thelightemittedfromtheplasmaiscollected,dispersedanddetected.Several
lfaosremraatinodn,saTmplepropertiesdeterminethethresholdforablationandsubsequentplasma
LIPSrequiresminimalornosamplepreparationandcananalyseanyphaseof
matter.Requiringonlyopticalaccess.LIPShaspossibleapplicationstoonlineprocess
monitoring.Inthesemiconductorindustry.LIPScanprovidespatially-resolved
elementalidentification.Depth-resolvedanalysisisalsopossibleifthelaserprobesa
samplerepetitivelyinonelocation.
LIPSasInattheicshwnioqruke,floarsesrpaatbilaaltlioyn-raensodlpveldasmmataefroiarlmsatcihoanraacrteersitzuadtiieodn,toTfhuertlhaesredreivseulsoepdto
dissertationprovidesanoverviewofmaterialscharacterizationandpresentsLIPSasa
usefulalternativetothemethodsalreadyinpractice.Chapterstwoandthreedevelopthe
theorybehindthethresholdforlaserablationandplasmaformationandreviewprevious
researchonthedeterminationofablationthresholds.Chapterfourdescribesthe
instrumentationused.Thetime-resolvedemissionofthelaser-inducedplasmaisstudied
iewnxapvcleholarepentsgetrthshsef.ievf5ef3ea2cntndsmosifxa.lnadsTeh1re0i6me4tmdinismas.nicoTcnhaiensdcfoiwnlaallveceetlxepedenragtitmh5eonlnatsaeslracmihprarlpaetdeiarabnl(cacethsiaoapnttetvrowlsouelvmaeesn.e)rThe
ablationthresholdiscalculatedforeachsamplestudied.
MATERIALSCHARACTECRHIEZMACITHCIAAOPLNTAAENNRADL1YSSUIRSFACETECHNIQUESFOR
Materialscharacterizationanddesignplayanimportantroleintechnology.
Scientistswanttodevelopmaterialswithidealproperties.Dependingontheintendeduse
ofdiematerial,severalsurfacesmightbeexplored.Forinstance,conosionandwear
characteristicscontrolamaterial'sstability.Thisisespeciallyevidentindieautomobile
andmedicalprosthesesindustries.Ifthesurfacebecomesdamaged,thematerialloses
function(I).Intheelectronicsindustry,surfacesarecarefullyfabricatedthrougha
systematicprocesssothatthemanufacturedcircuitperformsitsintendedfunction(2).
surfaceTphroepesrutrifeasceasrcofdemtoesrtmimnaetedraianldsthhaevseursfpaecciefitscdreevqeuliorpeemde,nthso.wOdnocesctihenetdisetssirkendow
whethertheyhaveachievedtheirgoal?Emergingtechnologiesrequiremicroanalydcal
Surfacesarcprobedwith6basicsourcesofenergy:electrons,ions,neutrals,
photons,healorfields.Theprobedsurfaceresponds,emittingelectrons,ions,neutrals,
Therefore,36differentclassesofsurfaceanalysisexist(2).Eachclasshasspecific
applicationsaswellassurfacerequiren
ticsaswellas
d.ThisisfollowedbyastructuralanalysFinallythe