Chigawo cha epitaxial ndi filimu yopyapyala ya kristalo imodzi yomwe imamera pa chigawo cha wafer kudzera mu njira ya epitaxial; chigawo cha wafer ndi filimu ya epitaxial zonse pamodzi zimatchedwa chigawo cha epitaxial. Pakati pa izi, kupanga chigawo cha epitaxial cha silicon carbide pa chigawo cha conductive silicon carbide kumapanga chigawo cha epitaxial cha silicon carbide chofanana, chomwe chingapangidwenso kukhala zida zamagetsi monga Schottky diodes, MOSFETs, ndi IGBTs. Mtundu wa chigawo chomwe chimagwiritsidwa ntchito kwambiri ndi chigawo cha 4H-SiC.
Popeza zipangizo zonse zimapangidwa pa zigawo za epitaxial, ubwino wa gawo la epitaxial umakhudza kwambiri magwiridwe antchito a chipangizocho. Komabe, ubwino wa gawo la epitaxial umakhudzidwa ndi kukonza kwa kristalo ndi substrate, zomwe zimaiika pamalo ofunikira kwambiri mumakampani ndikuchita gawo lofunikira pakukula kwake.
Njira zazikulu zopangira zigawo za epitaxial za silicon carbide ndi izi: kuyika nthunzi; epitaxy yamadzimadzi (LPE); epitaxy ya molecular beam (MBE); ndi chemical vapor deposition (CVD). Pakati pa izi, chemical vapor deposition (CVD) ndiyo njira yomwe imagwiritsidwa ntchito kwambiri pa 4H-SiC homogeneous epitaxy. 4H-SiC CVD epitaxy nthawi zambiri imagwiritsa ntchito zida za CVD, zomwe zimatsimikizira kuti kapangidwe ka kristalo ka 4H-SiC kamakhalabe kolimba pansi pa kutentha kwakukulu.
Mu zida za CVD, gawo lapansi silingaikidwe mwachindunji pamwamba pa chitsulo kapena kungoyikidwa pa maziko kuti liyike epitaxial, chifukwa izi zimakhudza zinthu zosiyanasiyana monga momwe mpweya umayendera (wopingasa, wowongoka), kutentha, kupanikizika, kukhazikika, ndi kuipitsidwa ndi tinthu tomwe timatuluka. Chifukwa chake, maziko othandizira amafunika; gawo lapansi limayikidwa pa thireyi, ndipo epitaxial imayikidwa pa gawo lapansi pogwiritsa ntchito ukadaulo wa CVD. Gawo lothandizira ili ndi maziko a graphite okhala ndi SiC.
Monga gawo lalikulu, gawo la graphite lili ndi mphamvu zapadera komanso modulus yeniyeni, komanso kutentha kwabwino komanso kukana dzimbiri. Komabe, popanga, graphite imakhudzidwa ndi dzimbiri komanso kutayika kwa ufa chifukwa cha mpweya wowononga komanso mankhwala otsala a organometallic, zomwe zimachepetsa kwambiri moyo wa ntchito ya gawolo. Nthawi yomweyo, ufa wa graphite wotsekedwa ukhoza kuipitsa tchipisi. Pakupanga ma wafers a silicon carbide epitaxial, zakhala zovuta kwambiri kukwaniritsa zofunikira kwambiri pazinthu za graphite, zomwe zimalepheretsa kwambiri chitukuko chawo komanso kugwiritsa ntchito bwino ntchito. Chifukwa chake,ukadaulo wokutirayatuluka ngati yankho.
Ubwino wa Zophimba za SiC mu Makampani Opanga Semiconductor
Kapangidwe kake ka zinthu zakuthupi ndi za mankhwala ziyenera kukwaniritsa zofunikira kwambiri kuti zisamatenthe kwambiri komanso dzimbiri, chifukwa izi zimakhudza mwachindunji kukolola kwa zinthu ndi moyo wa chinthucho. Zinthu za SiC zili ndi mphamvu zambiri, kuuma kwambiri, kuchuluka kochepa kwa kutentha, komanso kutentha kwambiri, zomwe zimapangitsa kuti zikhale zofunika kwambiri pakupanga zinthu komanso pakupanga zinthu za semiconductor. Zikagwiritsidwa ntchito pa zinthu za graphite, ubwino wake ndi monga:
1) SiC imateteza dzimbiri ndipo imatha kuphimba bwino gawo la graphite. Kuchuluka kwake kumateteza kuwonongeka ndi mpweya wowononga.
2) SiC ili ndi kutentha kwambiri komanso mphamvu yolimba yolumikizana ndi graphite substrate, zomwe zimapangitsa kuti chophimbacho chikhalebe bwino ngakhale kutentha kutakhala kochepa mobwerezabwereza.
3) SiC ili ndi kukhazikika kwabwino kwa mankhwala, kuteteza kulephera kwa utoto m'mlengalenga wotentha kwambiri komanso wowononga.
Kuphatikiza apo, ng'anjo za epitaxial zopangidwa ndi zinthu zosiyanasiyana zimafuna mathireyi a graphite okhala ndi mawonekedwe apadera a magwiridwe antchito. Kuchuluka kwa kutentha kwa zinthu za graphite kuyenera kugwirizana ndi kutentha kwa kukula kwa ng'anjo ya epitaxial. Mwachitsanzo, popeza kutentha kwa kukula kwa silicon carbide epitaxy kuli kokwera, mathireyi okhala ndi kuchuluka kwa kutentha kofanana ndi kuchulukira kwa kutentha amafunika. Kuchuluka kwa kutentha kwa SiC kumasiyana pang'ono ndi kwa graphite, zomwe zimapangitsa kuti ikhale chinthu chomwe chimakondedwa kwambiri pophimba pamwamba pa graphite substrates.
SiC imapezeka m'mitundu yosiyanasiyana ya makristalo, ndipo yodziwika kwambiri pakali pano ndi mitundu ya 3C, 4H, ndi 6H, iliyonse imagwira ntchito zosiyanasiyana. Mwachitsanzo, 4H-SiC imagwiritsidwa ntchito popanga zipangizo zamphamvu kwambiri; 6H-SiC ndiyo yokhazikika kwambiri ndipo imagwiritsidwa ntchito popanga zipangizo zamagetsi; ndipo 3C-SiC, chifukwa cha kufanana kwake ndi kapangidwe kake ndi GaN, imagwiritsidwa ntchito popanga zigawo za GaN epitaxial zopangira zipangizo za SiC-GaN RF. 3C-SiC imatchedwanso β-SiC. Ntchito yofunika kwambiri ya β-SiC ndi ngati filimu yopyapyala ndi zokutira; chifukwa chake, β-SiC pakadali pano ndiye chinthu chachikulu chomwe chimagwiritsidwa ntchito popanga zokutira.
Monga chinthu chogwiritsidwa ntchito kwambiri popanga zinthu za semiconductor, zophimba za SiC zimagwiritsidwa ntchito makamaka m'njira monga kukonzekera substrate, epitaxy, oxidation ndi diffusion, etching, ndi ion implantation. Makhalidwe akuthupi ndi a mankhwala a zophimba ayenera kukwaniritsa zofunikira kwambiri kuti zisamatenthe kwambiri komanso zisawonongeke, chifukwa izi zimakhudza mwachindunji kuchuluka kwa zinthu ndi moyo wa chinthu. Chifukwa chake, kukonzekera zophimba za SiC ndikofunikira kwambiri.
Njira Yokonzekera Zophimba za Silicon Carbide
Pakadali pano, njira zazikulu zopangira zophimba za SiC zikuphatikizapo njira ya sol-gel, njira yolumikizira, chophimba cha burashi, kupopera kwa plasma, reaction ya chemical vapor (CVR), ndi chemical vapor deposition (CVD).
Njira Yopatsira
Njira iyi ndi mtundu wa sintering yolimba kwambiri kutentha. Imagwiritsa ntchito makamaka chisakanizo cha ufa wa silicon (Si) ndi ufa wa carbon (C) ngati ufa wothira. Gawo la graphite limayikidwa mkati mwa ufa wothira ndikutenthedwa kutentha kwambiri mumlengalenga wopanda mpweya, zomwe zimapangitsa kuti SiC iphimbe pamwamba pa gawo la graphite. Njirayi ili ndi njira yosavuta komanso yolumikizana bwino pakati pa chophimbacho ndi gawo; komabe, chophimbacho sichimafanana bwino motsatira njira yokhuthala ndipo chimakhala ndi ma pores ambiri, zomwe zimapangitsa kuti pakhale kukana kwa okosijeni.
Njira Yophikira Burashi
Njira yophikira burashi imagwiritsa ntchito kugwiritsa ntchito zinthu zopangira madzi pamwamba pa graphite substrate, kenako n’kusakaniza zinthuzo ndi kutentha kwina kuti zipange pulasitiki. Njirayi ndi yosavuta komanso yotsika mtengo; komabe, pulasitiki yomwe imabwera chifukwa cha izi imakhala yolimba pang’ono pa pulasitiki, imakhala yofanana pang’ono, ndipo ndi yopyapyala komanso yokana kusungunuka, zomwe zimapangitsa kuti pakhale njira zina zowonjezera.
Njira Yopopera Madzi a M'magazi
Njira yopopera madzi a plasma imaphatikizapo kugwiritsa ntchito mfuti ya plasma kupopera zinthu zosungunuka kapena zosungunuka pang'ono pamwamba pa graphite substrate, zomwe kenako zimauma ndikugwirizana kuti zipange chophimba. Njirayi ndi yosavuta kugwiritsa ntchito ndipo imatha kupanga chophimba cha silicon carbide cholimba; komabe, chophimbacho nthawi zambiri chimakhala chopyapyala kwambiri, zomwe zimapangitsa kuti pakhale kukana kwa okosijeni. Chifukwa chake, nthawi zambiri imagwiritsidwa ntchito pokonzekera chophimba cha SiC kuti chiwongolere mtundu wa chophimba.
Njira ya Gel-Sol
Njira ya gel-sol makamaka ikuphatikizapo kukonzekera yankho la sol lofanana, lowonekera bwino kuti liphimbe pamwamba pa substrate. Pambuyo pouma mu gel, zinthuzo zimasiyidwa kuti zipange chophimba. Njirayi ndi yosavuta kugwiritsa ntchito ndipo ndi yotsika mtengo; komabe, chophimbacho chimakhala ndi zovuta monga kukana kutentha kwambiri komanso chizolowezi chosweka, zomwe zimalepheretsa kugwiritsidwa ntchito kwambiri.
Njira ya Chemical Nthunzi Yochitira Zinthu (CVR)
CVR imagwiritsa ntchito ufa wa Si ndi SiO₂ popanga nthunzi ya SiO₂ kutentha kwambiri, zomwe zimayambitsa machitidwe osiyanasiyana a mankhwala pamwamba pa gawo la Si kuti apange chophimba cha SiC. Chophimba cha SiC chomwe chimapangidwa ndi njira iyi chimamangirira mwamphamvu ku gawo la substrate; komabe, kutentha kwa reaction kumakhala kwakukulu, ndipo mtengo wake ndi wokwera kwambiri.
Kutaya Nthunzi ya Mankhwala (CVD)
Pakadali pano CVD ndiye ukadaulo waukulu wokonzekera zokutira za SiC pamwamba pa substrate. Njira yayikulu imaphatikizapo machitidwe angapo a physicochemical pakati pa ma reactants a gaseous ndi pamwamba pa substrate, zomwe zimapangitsa kuti SiC ikhazikike. Zophimba za SiC zopangidwa ndi ukadaulo wa CVD zimamangirirana mwamphamvu pamwamba pa substrate ndipo zimatha kukonza bwino kukana kwa okosijeni ndi kukana kwa ablation kwa zinthu za substrate; komabe, njira iyi imafuna nthawi yayitali yoyika, ndipo mpweya wochitapo kanthu uli ndi zinthu zina zoopsa.
Zochitika mu Zophimba za SiC
Zophimba za SiC zimagwiritsidwa ntchito makamaka ngati zogwiritsidwa ntchito popanga zinthu za semiconductor, ndi miyezo yofunika kwambiri ya magwiridwe antchito kuphatikizapo kufanana kwa zophimba, kuchuluka kwa kutentha, komanso kuyendetsa bwino kutentha. Ngakhale kuti pali kufunikira kwakukulu kwa zophimba za SiC ku China, ukadaulowu sunayambe kugwiritsidwa ntchito. Kunja kwa dziko, kampani imodzi yokha ya ku America imagwira ntchito m'munda umenewu, ndipo zinthu zake ndi zodula.
Mabwato a kristalondi zinthu zogwiritsidwa ntchito popanga epitaxial zomwe zingalowe m'malo mwa graphite yokhala ndi SiC, ngakhale kuti kuchuluka kwa msika ndi kochepa. Chotsatira ndi graphite yokhala ndi TaC, yomwe imapereka kukana kwabwino kwa mankhwala kuposa graphite yopanda kanthu kapena graphite yokhala ndi SiC, koma ndi yokwera mtengo kwambiri ndipo ikadali pachiyambi cha chitukuko. Pakadali pano, makampani am'nyumba mongaLiufang semiconductor, SemicerandiVetek Semiconductorakuchita kafukufuku ndi chitukuko m'derali.
Nthawi yotumizira: Meyi-20-2026