Cov Nyhuv Ntawm Cov Kub Sib Txawv Ntawm Kev Loj Hlob ntawm CVD SiC Txheej

CVD SiC Txheej yog dab tsi?

Kev siv tshuaj lom neeg los ua kom cov pa tawm (CVD) yog ib txoj kev siv lub tshuab nqus tsev los tsim cov khoom khov kho uas muaj cov khoom huv si. Cov txheej txheem no feem ntau siv rau hauv kev tsim cov khoom siv semiconductor los tsim cov zaj duab xis nyias nyias ntawm qhov chaw ntawm cov wafers. Hauv cov txheej txheem ntawm kev npaj silicon carbide los ntawm CVD, lub substrate raug rau ib lossis ntau cov khoom ua ntej uas tsis huv, uas teb rau ntawm qhov chaw ntawm lub substrate kom tso cov silicon carbide deposits uas xav tau. Ntawm ntau txoj hauv kev rau kev npaj cov ntaub ntawv silicon carbide, cov khoom uas tau npaj los ntawm kev siv tshuaj lom neeg los ua kom cov pa tawm muaj kev sib npaug thiab kev huv si ntau dua, thiab txoj kev no muaj kev tswj hwm cov txheej txheem zoo. Cov ntaub ntawv CVD silicon carbide muaj kev sib xyaw ua ke ntawm cov khoom siv thermal, hluav taws xob thiab tshuaj lom neeg zoo heev, ua rau lawv tsim nyog rau kev siv hauv kev lag luam semiconductor qhov twg xav tau cov ntaub ntawv ua tau zoo. Cov khoom siv CVD silicon carbide siv dav hauv cov khoom siv etching, cov khoom siv MOCVD, cov khoom siv Si epitaxial thiab cov khoom siv SiC epitaxial, cov khoom siv ua haujlwm thermal sai thiab lwm yam teb.

Tsab xov xwm no tsom mus rau kev tshuaj xyuas qhov zoo ntawm cov yeeb yaj kiab nyias nyias uas loj hlob ntawm ntau qhov kub thiab txias thaum lub sijhawm npajCVD SiC txheej, yog li xaiv qhov kub thiab txias tshaj plaws. Qhov kev sim siv graphite ua lub substrate thiab trichloromethylsilane (MTS) ua cov pa roj ua rau muaj kev cuam tshuam. Lub txheej SiC yog tso los ntawm cov txheej txheem CVD qis-siab, thiab micromorphology ntawmCVD SiC txheejraug soj ntsuam los ntawm kev siv lub tshuab hluav taws xob scanning los tshuaj xyuas nws qhov ceev ntawm cov qauv.

Vim tias qhov kub ntawm qhov chaw ntawm graphite substrate siab heev, cov roj nruab nrab yuav raug tshem tawm thiab tso tawm ntawm qhov chaw substrate, thiab thaum kawg C thiab Si uas tseem nyob ntawm qhov chaw substrate yuav tsim cov khoom SiC los tsim SiC txheej. Raws li cov txheej txheem loj hlob CVD-SiC saum toj no, nws tuaj yeem pom tias qhov kub thiab txias yuav cuam tshuam rau kev sib kis ntawm cov roj, kev rhuav tshem ntawm MTS, kev tsim cov tee dej thiab kev rhuav tshem thiab tso tawm ntawm cov roj nruab nrab, yog li qhov kub thiab txias yuav ua lub luag haujlwm tseem ceeb hauv cov qauv ntawm SiC txheej. Cov qauv me me ntawm cov txheej yog qhov qhia tau zoo tshaj plaws ntawm qhov ceev ntawm cov txheej. Yog li ntawd, nws yog qhov tsim nyog los kawm txog cov nyhuv ntawm cov kub sib txawv ntawm cov qauv me me ntawm CVD SiC txheej. Txij li thaum MTS tuaj yeem rhuav tshem thiab tso SiC txheej ntawm 900 ~ 1600 ℃, qhov kev sim no xaiv tsib qhov kub thiab txias ntawm 900 ℃, 1000 ℃, 1100 ℃, 1200 ℃ thiab 1300 ℃ rau kev npaj SiC txheej los kawm txog cov nyhuv ntawm qhov kub thiab txias ntawm CVD-SiC txheej. Cov kev ntsuas tshwj xeeb tau qhia nyob rau hauv Rooj 3. Daim duab 2 qhia txog cov qauv me me ntawm CVD-SiC txheej uas loj hlob ntawm qhov kub sib txawv.

Thaum qhov kub ntawm qhov tso tawm yog 900 ℃, tag nrho SiC loj hlob mus rau hauv cov duab fiber. Nws tuaj yeem pom tias lub cheeb ntawm ib lub fiber yog li 3.5μm, thiab nws qhov sib piv yog li 3 (<10). Ntxiv mus, nws yog tsim los ntawm ntau cov nano-SiC particles, yog li nws yog ib qho polycrystalline SiC qauv, uas txawv ntawm cov nanowires SiC ib txwm muaj thiab ib-siv lead ua SiC whiskers. Cov fibrous SiC no yog qhov tsis zoo ntawm cov qauv uas tshwm sim los ntawm cov txheej txheem tsis tsim nyog. Nws tuaj yeem pom tias cov qauv ntawm cov txheej txheem SiC no yog qhov xoob heev, thiab muaj ntau lub qhov hws ntawm cov fibrous SiC, thiab qhov ceev yog qis heev. Yog li ntawd, qhov kub no tsis haum rau kev npaj cov txheej txheem SiC ntom ntom. Feem ntau, cov qauv fibrous SiC tsis zoo yog tshwm sim los ntawm qhov kub tso tawm qis dhau. Thaum qhov kub qis, cov molecules me me adsorbed rau ntawm qhov chaw ntawm lub substrate muaj zog tsawg thiab tsis muaj peev xwm tsiv teb tsaws chaw. Yog li ntawd, cov molecules me me feem ntau tsiv teb tsaws chaw thiab loj hlob mus rau qhov qis tshaj plaws ntawm cov noob SiC (xws li qhov kawg ntawm cov noob). Kev loj hlob tas mus li thaum kawg tsim cov qauv fibrous SiC.

Kev Npaj ntawm CVD SiC Txheej:

Ua ntej, cov graphite substrate raug muab tso rau hauv lub cub tawg uas kub heev thiab khaws cia rau ntawm 1500 ℃ rau 1 teev hauv huab cua Ar rau kev tshem tawm tshauv. Tom qab ntawd lub graphite block raug txiav ua ib lub block ntawm 15x15x5mm, thiab qhov chaw ntawm lub graphite block raug polished nrog 1200-mesh sandpaper kom tshem tawm cov qhov hws uas cuam tshuam rau kev tso SiC. Lub graphite block kho tau ntxuav nrog anhydrous ethanol thiab dej distilled, thiab tom qab ntawd muab tso rau hauv qhov cub ntawm 100 ℃ rau kev ziab. Thaum kawg, lub graphite substrate raug muab tso rau hauv thaj chaw kub tseem ceeb ntawm lub cub tawg tubular rau SiC deposition. Daim duab qhia txog lub kaw lus tso pa tshuaj lom neeg tau qhia hauv Daim Duab 1.

LubCVD SiC txheejtau pom los ntawm kev siv lub tshuab hluav taws xob scanning los tshuaj xyuas nws qhov loj me thiab qhov ceev ntawm cov khoom me me. Tsis tas li ntawd, qhov kev tso tawm ntawm SiC txheej tau suav raws li cov qauv hauv qab no: VSiC = (m2-m1) / (Sxt) x 100% VSiC = Tus nqi tso tawm; m2 – qhov hnyav ntawm cov qauv txheej (mg); m1 – qhov hnyav ntawm lub substrate (mg); S-qhov chaw ntawm lub substrate (mm2); t - lub sijhawm tso tawm (h).   CVD-SiC nyuaj heev, thiab cov txheej txheem tuaj yeem sau ua ke raws li hauv qab no: thaum kub siab, MTS yuav dhau los ntawm kev rhuav tshem thermal los tsim cov pa roj carbon thiab silicon me me. Cov pa roj carbon me me feem ntau suav nrog CH3, C2H2 thiab C2H4, thiab cov pa roj silicon me me feem ntau suav nrog SiCI2, SiCI3, thiab lwm yam; cov pa roj carbon thiab silicon me me no yuav raug thauj mus rau saum npoo ntawm graphite substrate los ntawm cov roj nqa thiab cov roj diluent, thiab tom qab ntawd cov pa roj me me no yuav raug adsorbed rau ntawm qhov chaw ntawm lub substrate hauv daim ntawv ntawm adsorption, thiab tom qab ntawd cov tshuaj tiv thaiv yuav tshwm sim ntawm cov pa roj me me los tsim cov tee dej me me uas maj mam loj hlob, thiab cov tee dej kuj yuav fuse, thiab cov tshuaj tiv thaiv yuav nrog los ntawm kev tsim cov khoom nruab nrab (HCl roj); Thaum qhov kub nce mus txog 1000 ℃, qhov ceev ntawm SiC txheej tau zoo dua heev. Nws tuaj yeem pom tias feem ntau ntawm cov txheej yog tsim los ntawm SiC noob (kwv yees li 4μm loj), tab sis qee qhov fibrous SiC defects kuj pom, uas qhia tau tias tseem muaj kev loj hlob ntawm SiC ntawm qhov kub no, thiab cov txheej tseem tsis tau ntom txaus. Thaum qhov kub nce mus txog 1100 ℃, nws tuaj yeem pom tias SiC txheej yog ntom heev, thiab cov fibrous SiC defects tau ploj mus tag. Cov txheej yog tsim los ntawm cov khoom me me SiC uas muaj cov dej ntws nrog lub cheeb ntawm li 5 ~ 10μm, uas tau sib xyaw ua ke. Qhov saum npoo ntawm cov khoom me me yog ntxhib heev. Nws yog tsim los ntawm ntau cov nano-scale SiC noob. Qhov tseeb, CVD-SiC txoj kev loj hlob ntawm 1100 ℃ tau dhau los ua kev hloov pauv loj. Cov molecules me me adsorbed rau ntawm qhov chaw ntawm lub substrate muaj lub zog thiab lub sijhawm txaus los nucleate thiab loj hlob mus rau hauv SiC noob. Cov SiC noob sib npaug tsim cov dej loj. Nyob rau hauv qhov kev ua ntawm lub zog saum npoo av, feem ntau ntawm cov tee dej zoo li kheej kheej, thiab cov tee dej tau sib xyaw ua ke kom nruj nreem los ua ib txheej SiC ntom ntom. Thaum qhov kub nce mus txog 1200 ℃, SiC txheej kuj tseem ntom, tab sis SiC morphology dhau los ua ntau-ridged thiab qhov chaw ntawm lub txheej zoo li rougher. Thaum qhov kub nce mus txog 1300 ℃, ntau tus ntawm cov khoom me me uas muaj lub cheeb ntawm li 3μm pom nyob rau ntawm qhov chaw ntawm graphite substrate. Qhov no yog vim tias ntawm qhov kub no, SiC tau hloov mus ua roj theem nucleation, thiab MTS decomposition rate yog ceev heev. Cov molecules me me tau reacted thiab nucleated los tsim SiC noob ua ntej lawv raug adsorbed rau ntawm qhov chaw substrate. Tom qab cov noob tsim cov khoom me me, lawv yuav poob qis dua, thaum kawg ua rau SiC noob xoob nrog qhov ceev tsis zoo. Nws yog qhov tseeb, 1300 ℃ tsis tuaj yeem siv ua qhov kub tsim ntawm SiC txheej tuab. Kev sib piv tag nrho qhia tau hais tias yog tias yuav tsum npaj SiC txheej tuab, qhov kub tso CVD zoo tshaj plaws yog 1100 ℃.

Daim Duab 3 qhia txog qhov nrawm ntawm CVD SiC txheej ntawm qhov kub sib txawv. Thaum qhov kub nce ntxiv, qhov nrawm ntawm SiC txheej maj mam txo qis. Qhov nrawm ntawm 900 ° C yog 0.352 mg·h-1/mm2, thiab kev loj hlob ntawm cov fibers ua rau qhov nrawm nrawm tshaj plaws. Qhov nrawm ntawm txheej nrog qhov ceev tshaj plaws yog 0.179 mg·h-1/mm2. Vim yog qhov nrawm ntawm qee cov SiC me me, qhov nrawm ntawm 1300 ° C yog qhov qis tshaj plaws, tsuas yog 0.027 mg·h-1/mm2.   Xaus Lus: Qhov kub zoo tshaj plaws ntawm CVD deposition yog 1100 ℃. Qhov kub qis ua rau SiC loj hlob sai, thaum qhov kub siab ua rau SiC tsim cov pa dej thiab ua rau muaj cov txheej txheem tsis sib xws. Nrog rau qhov kub nce ntxiv, qhov nrawm ntawm deposition ntawmCVD SiC txheejmaj mam txo qis.