D

Damping135●DDDACdigital-to-analogconverterDahms–Rufftheory—Forfastelectronexchangepro-cessescoupledtoisothermaldiffusioninsolution,thetheoreticaldescriptionanditsexperimentalver-ificationweregivenbyDahms[i]andbyRuffandco-workers[ii–v].Ruffandco-workersstudiedthedis-placementofthecentersofmassparticles,whichisbroughtaboutbybothcommonmigrationalmotionandchemicalexchangereactionofthetypeA+AXAX+A()Itwasconcludedthattheexchangereaction(electronhopping)canbedescribedintermsofsecond-orderki-netics,andarelationshipwasgivenbetweenthemea-sureddiffusioncoefficient(D)andthediffusioncoef-ficient(Do)thatwouldbemeasuredintheabsenceofanyelectronexchangereaction:D=Do+keδπc=Do+Dc,()wherekeisthesecond-orderrateconstantoftheex-changereactionandcandδaretheconcentrationandthedistancebetweenthecentersofthechemicallyequiv-alentspeciesinvolvedintheelectronexchange,respec-tively.Infact,δisthedistancewithwhichthehy-drodynamicdisplacementisshortenedforthespeciesandcanbedeterminedoratleastestimatedonthebasisofindependentdata,e.g.,theresultsofneutronscattering.Later,Ruff,andBotár[vi]correctedtheoriginalther-modynamicderivation,whichwasaffectedbysomeer-rors.Accordingtothecorrectedthermodynamicaltreat-ment,theconstantfactorinEq.()is,,or(in-steadofπ)forthree-,two-,andone-dimensionaldif-fusion,respectively,i.e.,D=Do+keδc.()Theyalsousedarandom-walktreatmenttodescribetheelectron-hoppingprocesscoupledtophysicaldiffu-sion[vii].Refs.:[i]DahmsH()JPhysChem:;[ii]RuffI,FriedrichVJ()JPhysChem:;[iii]RuffI,FriedrichVJ,DemeterK,CsillagK()JPhysChem:;[iv]RuffI,FriedrichVJ()JPhysChem:;[v]RuffI,FriedrichVJ()JPhysChem:;[vi]BotárL,RuffI()ChemPhysLett:;[vii]RuffI,BotárL()JPhysChem:GIDamasceneprocess—Thesingleordualdamascenecopperelectroplatingmethodrepresentsoneofthenowadaysmostsignificantcopperprocessingtechnolo-gies,whichisappliedinthemicroprocessorproductionforhigh-qualitycopperinterconnectsforintegratedcir-cuitchips.Ofspecialimportancewerethechangesofthewiringmaterialfromaluminumtocopper,aswellasfromsilicondioxidestonewerlow-Kmaterials(seeinsulator)inthatbranch.Indamasceneprocessing,thedielectricmaterialisdepositedfirstasablanketfilm,andispatternedandetchedleavingholesortrenches.Inthefollowingstep,single,andduald.p.aredistin-guished:Inthefirstone,copperisfirstlydepositedintheholesortrenchessurroundedbyathinbarrierfilm,necessarytopreventcopperdiffusionintothedielectric,resultinginfilledviasorwirelines,respectively.Intheduald.p.technology,boththetrenchandviaarefabri-catedbeforethedepositionofcopper,resultinginfor-mationofboththeviaandlinesimultaneously.Thatis,onlyasinglemetaldepositionstepisusedtosimulta-neouslyformthemainmetallinesandthemetalinthevias.Morerecently,thenumberofinterconnectlevelsforlogichassubstantiallyincreasedduetothelargenumberoftransistorsthatarenowinterconnectedinamodernmicroprocessor.Thus,especiallytheapplicationoftheduald.p.canreducethenumberofprocessingstepsandreducecosts,butneverthelessensuresaperformanceen-hancement.Refs.:[i]WolfS()SiliconprocessingfortheVLSIera,deep-submicronprocesstechnology,vol..LatticePress,SunsetBeach;[ii]An-dricacosPC()Interface:;[iii]StickneyJL()Electrochem-icalatomiclayerepitaxy(EC-ALE):Nanoscalecontrolintheelectrode-positionofcompoundsemiconductors.In:AlkireRC,KolbDM(eds)Advancesinelectrochemicalscienceandengineering,vol.Wiley-VCH,Weinheim,pp–MHerDamping—Diminishingoftheamplitudeofoscil-lations.Electricaldampingofthecurrentoscillationscausedbythedroppingmercuryelectrodewasusedinpolarography.Dampingisalsousedtodimin-ishhigher-frequencycontributionstonoise;however,greatcarehastobetakennottocauseover-damping,i.e.,toobscurethetime-dependencethatissupposedtobestudied.FS136Daniell,JohnFrederic●DDaniell,JohnFredericEnglishscientist(March,,London,UK–March,,London,UK)ThefirstprofessorofchemistryatKingsCollege,London,in.Firstinvestigationsinbatteriescoincidedwiththeappearanceofcommercialtelegraphsystems.Thefastelectrodekineticsofthecop-perandzincelectrodesintheDaniellcell()en-abledtheiruseintherapidlygrowingtelegraphsystemsemployingtheMorsecode.InDaniellproducedastrongelectricarcwitha-cellbattery.Hedemon-stratedthatmetalionsarecarriersofelectricchargeinametal–saltsolutioninsteadofthemetaloxides.HewasafriendandadmirerofFaraday,tohimhededicatedhistextbookIntroductiontotheStudyofChemicalPhi-losophy().Refs.:[i]MagnussonM(ed)()Chambersbiographicaldictionary.W&Chambers,Edinburgh;[ii]CrystalD(ed)()TheCambridgebiographicalencyclopedia.CambridgeUniversityPress,CambridgeRHDaniellcell—Electrochemicalprimarycellcomposedofazincandacopperelectrode.Bothmetalsareim-mersedintoaqueoussolutionsoftheirrespectivesul-fates(describedaccordingtotheStockholmconven-tion),thesolutionsareseparatedby,e.g.,aporousglassfrit:−ZnZn+Cu+Cu+.ThecathodereactionisthereductionofcoppercationsCu++e−Cu.TheanodereactionistheoxidationofzincZnZn++e−.ThecellreactionisCu++ZnZn++Cu.Evenunderopen-circuitconditionsdiffusionofio