device_models - ECE145A\/218CA notes M Rodwell copyrighted ECE145a 218a Notes Set 3 218 device models device characteristics characteristics Mark Rodwell

device_models - ECE145A/218CA notes M Rodwell copyrighted...

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ECE145A /218CA notes, M. Rodwell, copyrightedECE145/ 218N tS t 3ECE145a / 218a: Notes Set 3 device models &device characteristics:device characteristics:Mark RodwellUniversity of California, Santa Barbara [email protected] 805-893-3244, 805-893-3262 fax
ECE145A /218CA notes, M. Rodwell, copyrightedObjectives:Train both seniors graduate students in:--high frequency circuit designfast analog, fast digital, RF/microwave/mm-wave ICs--high frequency transistor design and modeling--145B and 145C are applied / 145A covers the fundamentals
Active Devices:Active Devices: Bipolar TransistorsBipolar Transistors
ECE145A /218CA notes, M. Rodwell, copyrightedHBT Physical Structure
ECE145A /218CA notes, M. Rodwell, copyrightedPhysical structure, symbolicdrawinglar toperpendicuLengthStripeDeviceEL=emitterb,contWeWebWEB gradebaseemittercontactbase contactbase contactEB gradeBC gradecollectorN+ sub collectordWN- drift collectorcollector contactTsemi-insulating InP substratecTunderWbTWcW
ECE145A /218CA notes, M. Rodwell, copyrightedBipolar Transistor DC-IV Characteristics
ECE145A /218CA notes, M. Rodwell, copyrightedBipolar Transistor: DC characteristics: common-emitterVce,sat1520m210-410-2(A)IcI510mA/μmbcIIβ=1010-810-6Ic , Ib(Ib001234V10-1210-100 0.25 0.5 0.75 1VceVbr,ceoVbe(V)
ECE145A /218CA notes, M. Rodwell, copyrightedBipolar Transistor: Carrier Transit Times
ECE145A /218CA notes, M. Rodwell, copyrightedBase resistance & collector-base capacitance drawinglar toperpendicuLengthStripeDeviceEL=121612emitterunder spreadingcontact under spreadingrmcontact te__,sheetbaseEEsheetbaseEcontactbcontbEcontactbbbbLWLWWLRR++++ρρρtorsemiconduc,eccbEEcontbETLWCε2008Feb.IEEEProc.2001,Nov.EDLIEEERodwell(seeclassofscopebeyondDetailsandintoofsplittingddistributeareandcbicbxcbcb bbcCCCCRT
ECE145A /218CA notes, M. Rodwell, copyrightedHBT hybrid-Pi equivalent-circuit modelCCcbx)exp(cmomjggωτ=CCcbiRbbBCRcmbegR/β=cbfτ+τ=τRbeVbegmVbee-jωτcmbeERexCjeCbe,diff=gmτfThe delay associated with the gm element is essential if common-base input impedance is to be modeled correctly at high frequencies.
ECE145A /218CA notes, M. Rodwell, copyrightedBipolar Transistor T-modelCcbxCcbi()ωτωτ+αωαexp11)(0cbjjBCRbbRcbα(ω)∗I’eωτ+ωτ+α111110cbjjVbeBRceI’eτ+τω+α)(10bbjERexCbe,deplre=1/gmEThe approximations above, if taken to first order in ω, produce the hybrid pi model.The T model is more convenient for common-base amplifier analysis.
Active Devices:Active Devices: Field-Effect Transistorsin General
ECE145A /218CA notes, M. Rodwell, copyrightedFETs: Basic OperationchdC/~DACgsεchd/where/electrongdvLQI==ττgsdschdgsgsVCVCQδδδ+=ττδδδ/and/wherechdgdgsmdsdsgsmdCGCgVGVgI==+=
ECE145A /218CA notes, M. Rodwell, copyrighted

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