Introduction
Storageunit:Therearealargenumberofstorageelementsinthememory,whicharedividedintogroupsaccordingtothesamebit,andallthestorageelementsinthegrouparereadorwrittenatthesametime,Suchagroupofstorageelementsiscalledastorageunit.Astorageunitcanusuallystoreonebyte;thestorageunitisthebasicunitfortheCPUtoaccessthememory.
Storageunit
Thesmallestunitofinformationinacomputerisabit,whichisabinarybit.8bitsformaByte,whichisabyte.Astorageunitcanstoreonebyte,thatis,8binarybits.Thememorycapacityofacomputeriscalculatedwithbytesasthesmallestunit.Foramemorywith128storageunits,itcanbesaidthatitscapacityis128bytes.Ifthereisa1KBmemory,ithas1024storageunits,anditsnumberisfrom0-1023.Thememoryisdividedintoanumberofstorageunits,andeachstorageunitisnumberedsequentiallyfrom0.Forexample,amemoryhas128storageunits,anditsnumberisfrom0to127.
Thestorageaddressisgenerallyrepresentedbyahexadecimalnumber,andeachmemoryaddressstoresasetofbinary(orhexadecimal)numbers,usuallycalledthecontentoftheaddress.Itisworthnotingthattheaddressofthestorageunitandthecontentoftheaddressaredifferent.Theformeristhenumberofthestorageunit,whichrepresentsalocationinthememory,andthelatterrepresentsthedatastoredinthislocation.Justasoneistheroomnumberandtheotheristhepersonlivingintheroom.
Thestorageunitthatstoresamachineword,usuallycalledwordstorageunit,andthecorrespondingunitaddressiscalledthewordaddress.Theunitthatstoresonebyteiscalledbytestorageunit,andthecorrespondingaddressiscalledthebyteaddress.Ifthesmallestunitthatcanbeaddressedinacomputerisawordstorageunit,thenthecomputeriscalledaword-addressedcomputer.Ifthesmallestaddressableunitinacomputerisabyte,thenthecomputeriscalledabyte-addressablecomputer.Ifthemachinewordlengthisequaltothenumberofbitsofthememoryunit,amachinewordcancontainseveralbytes,soamemoryunitcanalsocontainseveralbyteaddressesthatcanbeindividuallyaddressed.Forexample,a16-bitbinarywordstorageunitcanstoretwobytes,whichcanbeaddressedbywordaddressorbyteaddress.Whenaddressingwithabyteaddress,a16-bitmemorycelloccupiestwobyteaddresses.
Thesmalleststaticstorageunit
OnAugust18,2008,IBM,AMD,andtheSchoolofNanoscienceandEngineering(CNSE)oftheStateUniversityofNewYorkatAlbanyjointlyannouncedthatTheworld'sfirst22nmnodeeffectivestaticrandomaccessmemory(SRAM)wassuccessfullydeveloped.Thisisalsotheworld'sfirstannouncementtoproduceaneffectivestorageunitina300mmresearchfacilityenvironment.SRAMchipsaremorecomplexdevices,suchasthe"pioneers"ofmicroprocessors.ThesizeoftheSRAMcellisakeytechnicalindicatorinthesemiconductorindustry.ThelatestSRAMcellusesatraditionalsix-transistordesignandoccupiesonly0.1squaremicrons,breakingthepreviousSRAMsizereductionbarrier.
ThenewresearchworkwasdoneattheSchoolofNanoscienceandEngineering(CNSE)oftheStateUniversityofNewYorkatAlbany,wheremanytopsemiconductorresearchesbyIBMandotherpartnersarecarriedout.Dr.TCChen,VicePresidentofIBMTechnologyR&DDepartment,said,“Weareresearchingattheultimateedgeofpossibilityandmovingtowardsadvancednext-generationsemiconductortechnology.Newresearchresultscanbesaidtocontinuetodrivethepursuitofminiaturizationofmicroelectronicdevices.It’simportant."
22nanometersarethenexttwogenerationsofchipmanufacturing,andthenextgenerationis32nanometers.Inthisregard,IBManditspartnersaredevelopingtheirunparalleled32-nanometerhigh-Kmetalgatetechnology(high-Kmetalgatetechnology).
Traditionallyspeaking,SRAMchipsaremademorecompactbyshrinkingthebasicbuildingunits.ResearchersfromtheIBMAllianceoptimizedthedesignandcircuitdiagramoftheSRAMcelltoimprovestability.Inaddition,inordertomanufactureanewSRAMcell,theyalsodevelopedseveralnewmanufacturingprocesses.Researchersusedhigh-NAimmersionlithography(high-NAimmersionlithography)technologytocarveoutthepatterndimensionsanddensity,andfabricatedrelatedpartsinanadvanced300mmsemiconductorresearchenvironment.
KeytechnologiesrelatedtoSRAMcellsinclude:sidebandhigh-Kmetalgates,<25nmgatelengthtransistors,ultra-thinspacers,co-doping,advancedactivationtechnology,extremelyThinsilicidefilmandembeddedcoppercontacts,etc.
ItisreportedthattherewillbeaspecialreporttointroducethedetailsofthelatestresultsattheIEEEInternationalElectronicEquipment(IEDM)AnnualConferencetobeheldinSanFrancisco,USAfromDecember15to17,2008.
Relatedapplications
Inacomputer,theinstructionsetexecutedbythearithmeticunitisinterpretedbythecontrollerasawell-definedsimpleinstructionsetwithaverylimitednumber.Generallycanbedividedintofourcategories:1),datamovement(suchas:copyavaluefromstorageunitAtostorageunitB)2),digitallogicoperations(suchas:calculatethesumofstorageunitAandstorageunitB,theresultisreturnedStorageunitC)3),conditionverification(forexample:ifthevalueinstorageunitAis100,thenextinstructionaddressisstorageunitF)4),theinstructionsequenceismodified(forexample:thenextinstructionaddressisstorageunitF)