Kev Tshawb Fawb Txog Kev Txhim Kho thiab Depletion MOSFETs

D-FET yog nyob rau hauv 0 lub rooj vag kev tsis ncaj ncees thaum muaj cov channel, tuaj yeem ua tus FET; E-FET yog nyob rau hauv 0 lub rooj vag bias thaum tsis muaj channel, tsis tuaj yeem ua tus FET. Ob hom FETs no muaj lawv tus yam ntxwv thiab siv. Feem ntau, txhim kho FET nyob rau hauv high-speed, low-power circuits yog qhov tseem ceeb heev; thiab cov cuab yeej no ua haujlwm, nws yog qhov polarity ntawm lub rooj vag bias voltage thiab ntws voltage ntawm tib yam, nws yog yooj yim dua nyob rau hauv Circuit Court tsim.

Lub thiaj li hu ua enhanced txhais tau tias: thaum VGS = 0 raj yog ib tug txiav-tawm xeev, ntxiv rau qhov tseeb VGS, feem ntau ntawm cov cab kuj yog attracted rau lub rooj vag, yog li "txhim kho" cov cab kuj nyob rau hauv lub cheeb tsam, tsim ib tug conductive channel. n-channel txhim kho MOSFET yog qhov pib ntawm sab laug-txoj cai symmetrical topology, uas yog P-hom semiconductor ntawm lub cim ntawm ib txheej ntawm SiO2 zaj duab xis rwb thaiv tsev. Nws tsim ib txheej insulating ntawm SiO2 zaj duab xis ntawm P-hom semiconductor, thiab tom qab ntawd diffuses ob qhov chaw doped N-hom los ntawmphotolithography, thiab ua electrodes los ntawm N-hom cheeb tsam, ib qho rau qhov ntws D thiab ib qho rau qhov chaw S. Ib txheej ntawm cov hlau txhuas yog plated rau ntawm insulating txheej ntawm qhov chaw thiab qhov ntws raws li lub rooj vag G. Thaum VGS = 0 V , muaj ob peb lub diodes nrog rov qab-rau-rov qab diodes ntawm qhov ntws thiab qhov chaw thiab qhov hluav taws xob ntawm D thiab S tsis tsim tam sim no ntawm D thiab S. Qhov tam sim no ntawm D thiab S tsis yog tsim los ntawm qhov siv hluav taws xob. .

Thaum lub rooj vag voltage ntxiv, yog 0 < VGS < VGS (th), los ntawm lub capacitive electric teb tsim ntawm lub rooj vag thiab lub substrate, lub polyon qhov nyob rau hauv lub P-hom semiconductor nyob ze rau hauv qab ntawm lub rooj vag yog repelled downward, thiab ib tug nyias depletion txheej ntawm tsis zoo ions tshwm; Nyob rau tib lub sijhawm, nws yuav nyiam cov oligons nyob rau hauv kom txav mus rau txheej txheej saum npoo, tab sis tus naj npawb raug txwv thiab tsis txaus los tsim cov kab hluav taws xob uas sib txuas lus cov dej ntws thiab qhov chaw, yog li nws tseem tsis txaus rau Tsim cov dej ntws tam sim no. nce ntxiv VGS, thaum VGS > VGS (th) (VGS (th) yog hu ua tig-on voltage), vim hais tias lub sij hawm no lub rooj vag voltage tau kuj muaj zog, nyob rau hauv lub P-hom semiconductor nto txheej nyob ze rau hauv qab ntawm lub rooj vag hauv qab no sib sau ua ke ntawm ntau. electrons, koj tuaj yeem tsim ib lub trench, qhov ntws thiab qhov chaw ntawm kev sib txuas lus. Yog tias qhov hluav taws xob ntws tawm tau ntxiv rau lub sijhawm no, cov dej ntws tam sim no tuaj yeem tsim ID. electrons nyob rau hauv lub conductive channel tsim hauv qab lub rooj vag, vim hais tias ntawm lub carrier qhov nrog P-hom semiconductor polarity yog opposite, yog li nws yog hu ua anti-type txheej. Raws li VGS nce ntxiv, ID yuav nce ntxiv. ID = 0 ntawm VGS = 0V, thiab qhov ntws tawm tam sim no tsuas yog tom qab VGS > VGS(th), yog li, hom MOSFET no hu ua kev txhim kho MOSFET.

Kev tswj kev sib raug zoo ntawm VGS ntawm cov dej ntws tam sim no tuaj yeem piav qhia los ntawm qhov nkhaus iD = f(VGS(th)) | VDS = const, uas yog hu ua qhov hloov pauv tus yam ntxwv nkhaus, thiab qhov loj ntawm txoj kab nqes ntawm qhov hloov pauv tus yam ntxwv nkhaus, gm, qhia txog kev tswj cov dej ntws los ntawm lub qhov rooj qhov hluav taws xob. qhov loj ntawm gm yog mA / V, yog li gm tseem hu ua transconductance.