Internal qauv ntawm NAND Flash

Xyoo 1965, tom qab lub raj bipolar tau tsim los ntawm W. Shockley, W. Brattain thiab J. Bardeen, Gordon Moore, tus tsim ntawm Intel, nrhiav tau txoj cai zoo li no: thaum tus nqi tseem tsis tau hloov pauv, lub zog uas tuaj yeem ua tau. accommodated nyob rau hauv ib tug integrated circuit Tus naj npawb ntawm transistors yuav ob npaug rau txhua txhua xyoo, thiab qhov kev ua tau zoo kuj yuav ob npaug. Qhov tseeb, tus naj npawb ntawm cov transistors ntawm ib qho kev sib koom ua ke yuav muab ob npaug rau txhua 18 lub hlis nyob rau ob peb xyoos tom ntej no. Piv txwv li, nyob rau hauv 18 lub hlis ntawm Pentium 1.3 thiab Pentium 4, tus naj npawb ntawm transistors ib cheeb tsam tau nce los ntawm 28 lab mus rau 55 lab.

Niaj hnub no, kev khiav hauj lwm zaus ntawm lub processor ntawm tus qauv desktop PC yog xam nyob rau hauv gigahertz, thiab lub peev xwm cov ntaub ntawv uas lub cim xeeb khaws cia yog xam nyob rau hauv terabytes (TB).Qhov no nce nyob rau hauv tus naj npawb ntawm transistors ib cheeb tsam yog piv txwv los ntawm lub cim xeeb, uas kuj tshwm sim los ua ib qho tseem ceeb hauv cov tshuab hluav taws xob.

Semiconductor nco tuaj yeem muab faib ua ob qhov tseem ceeb: RAM (Random Access Memories) thiab ROM (Nyeem Tsuas Nco): RAM yuav ploj tom qab lub hwj chim kaw, thaum ROM yuav khaws cia. Lwm hom kev nco, NVM (Non-Volatile Memories), nyob nruab nrab ntawm ob hom saum toj no. Nws cov ntsiab lus tuaj yeem hloov kho, thiab cov ntaub ntawv yuav tsis ploj tom qab lub zog tsis ua haujlwm. Qhov no yog qhov hloov pauv ntau dua li ROM ntshiab, vim tias cov ntsiab lus ntawm ROM yog sau los ntawm cov chaw tsim khoom thiab tsis tuaj yeem hloov kho los ntawm cov neeg siv khoom.

Keeb kwm ntawm Non-Volatile Memories pib nyob rau hauv 1970s, thiab thawj NVM yog EPROM (Erasable Programmable Read Only Memory), txij thaum ntawd los txog rau xyoo 1990, NVM tau maj mam dhau los ua ib tus tswv cuab tseem ceeb tshaj plaws ntawm tsev neeg semiconductor, thiab ntau dua. tau them nyiaj rau kev txhim kho cov thev naus laus zis tshiab los txhawb kev nce qib ntawm NVM ntau dua li cov txiaj ntsig kev lag luam.

Txij li thaum xyoo 1990, raws li lub cim xeeb semiconductor tau nkag mus rau cov khoom lag luam digital xws li xov tooj ntawm tes, khoos phis tawj tes, thiab cov koob yees duab video, lub khw no tau nyob hauv lub xeev ntawm kev loj hlob sai mus txog niaj hnub no.

Qhov nrov tshaj plaws Flash nco txoj kev cia yog raws li lub tshuab hu ua Floating Gate (FG). Koj tuaj yeem xa mus rau daim duab hla ntu hauv qab no. MOS raj yog tsim los ntawm ob lub qhov rooj sib tshooj: thawj zaug yog tag nrho los ntawm oxides; thaum qhov thib ob txuas nrog rau sab nraud. Lub qhov rooj ib leeg no sib npaug rau kev tsim cov khoom siv hluav taws xob sib cais, uas ua kom ntseeg tau tias cov khoom siv hluav taws xob (cov ntaub ntawv) hauv nws tuaj yeem khaws cia tau ntau xyoo. Cov txheej txheem ntawm kev them nyiaj thiab tso tawm qhov kev sib cais no yog hu ua program thiab lwv. Vim yog qhov kev them nyiaj thiab tso tawm, qhov muaj peev xwm Vth hauv qhov kev sib cais yuav raug hloov pauv; Qhov no yog lub hauv paus ntsiab lus ntawm kev ua haujlwm ntawm MOS raj. Thaum peb siv qhov hluav taws xob rau lub cim xeeb ntawm tes, peb tuaj yeem paub qhov txawv ntawm ob qhov xwm txheej: thaum qhov hluav taws xob peb thov siab dua Vth, nws raug lees paub tias yog "1", txwv tsis pub nws raug lees paub tias yog "0".

NAND nco cell qauv

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Cov chav nyob ntawm lub cim xeeb tau teeb tsa hauv daim ntawv ntawm matrix, vim tias lub koom haum no tuaj yeem txo qhov chaw nyob ntawm lub cim xeeb. Kuv tuaj yeem qhia qhov txawv ntawm NAND thiab NOR Flash los ntawm saib lub koom haum ntawm lub cim xeeb hlwb. Peb qhia NAND tam sim no, vim NAND yog lub cim xeeb siv dav tshaj plaws tam sim no.

Hauv NAND architecture, lub cim xeeb hlwb raug teeb tsa hauv cov koob txhua 32 lossis 64 raws li qhia hauv daim duab 2.2. Ob lub transistors rau xaiv (ob lub pins sab nraud ntawm lub transistor no yog DSL / Mdl [txuas mus rau BL] lossis SSL / Msl [txuas mus rau SL]) tau muab tso rau ntawm ob qho kawg ntawm txhua txoj hlua ntawm lub cim xeeb hlwb (32 lossis 64) kom qhov no ua kom ntseeg tau. kev txuas mus rau qhov chaw kab (ntawm Msl) thiab bitline (ntawm Mdl). Txhua NAND nco cell hlua muaj ib tug bitline siv los txuas rau lwm cov hlua. Cov rooj vag tswj yog siv los txuas cov kab lus (WLs).

Cov nplooj ntawv logical yog ib feem tswj los ntawm chav tsev khaws cia tswj los ntawm tib lo lus. Tus naj npawb ntawm nplooj ntawv tswj hwm los ntawm txhua kab lus muaj feem cuam tshuam nrog lub peev xwm ntawm chav tsev cia khoom. Raws li qhov chaw cia ntawm chav tsev cia, Flash nco tuaj yeem muab faib ua ntau pawg: SLC (ib chav cia 1 ntsis), MLS (ib chav cia 2 ntsis), 8LC (ib chav cia 3bits), 16LC (ib chav cia 4bits) .

Yog tias peb xav txog cov ntaub ntawv sib cuam tshuam ntawm SLC, cov lej khib thiab tus lej sib txawv ntawm nplooj ntawv sib txawv. Ib qho piv txwv yog: kab lus SLC nrog nplooj ntawv loj ntawm 4KB (4096 * 8=32768 khoom) muaj 65536 qhov chaw nco.

Tau kawg, yog tias nws yog MLC, muaj 4 nplooj ntawv, thiab txhua lub cim xeeb ntawm tes muaj ib qho LSB (tseem ceeb heev ntsis) thiab ib MSB (Qhov Tseem Ceeb Tshaj Plaws). Yog li ntawd muaj:

- MSB thiab LSB nplooj ntawv txawm bitlines

- MSB thiab LSB nplooj ntawv ntawm khib bitlines

Txhua NAND lub cim xeeb ntawm cov hlua ntawm tib lo lus raug tshem tawm ua ke thaum tshem tawm, yog li tsim ib qho thaiv (blcok), yog tias ob lub thaiv tau pom hauv 2.2, tib lub npav siv, ib qho thaiv yog tsim los ntawm WL0<63:0>thiab lwm tus yog WL1<63:0>.

Lub cim xeeb ntawm tes qauv ntawm NAND Flash yog matrix. Yuav tsum muaj cov circuits ntxiv thaum nyeem ntawv, sau ntawv thiab tshem tawm NAND. Txij li txhua qhov tuag ntawm NAND yuav tsum tau ntim, ib qho tsim nyog tau teeb tsa hauv theem tsim. Nws yog ib qho tseem ceeb rau qhov loj me thiab tsim cov khoom siv hluav taws xob nyob ib puag ncig. Piv txwv li, cov qauv hierarchical ntawm txhua qhov tuag ntawm NAND Flash yog zoo li no.

Daim duab 2.3 qhia ib qho piv txwv ntawm hierarchy. Lub chaw cia khoom tuaj yeem teeb tsa ua ntau lub dav hlau (ob lub dav hlau hauv daim duab 2.3), cim nrog cov kab lus nyob rau hauv kab rov tav thiab cov kab hauv kab ntsug.

Cov Kab Decoder nyob nruab nrab ntawm ob lub dav hlau. Ib qho ntawm cov dej num ntawm lub voj voog yog ua kom tsis zoo rau cov kab lus ntawm cov NAND cov hlua xaiv kom ua haujlwm zoo. Tag nrho cov bitlines yuav tsum tau txuas nrog rau kev nkag siab amplifiers (Sense Amp). Txhua qhov kev nkag siab amplifier tuaj yeem muaj ib lossis ntau dua bitlines, uas peb yuav qhia kom meej tom qab hauv nqe lus no. Lub hom phiaj ntawm kev nkag siab amplifier yog los hloov cov tam sim no hauv lub cim xeeb ntawm tes mus rau ib qho digital. Hauv cheeb tsam peripheral, muaj qee yam khoom siv uas yuav tsum tau them rau lub cim xeeb ntawm lub hlwb, nrog rau cov khoom siv tswj hluav taws xob, cov logic circuits, thiab lwm yam khoom siv. PADs yog siv los sib txuas lus nrog cov khoom siv sab nraud.