1. Chifukwa chiyani pali azokutira za silicon carbide
Epitaxial wosanjikiza ndi filimu imodzi yopyapyala ya kristalo yomwe imakula pamaziko a chofufumitsa kudzera munjira ya epitaxial. Wowonda wam'munsi ndi filimu yopyapyala ya epitaxial pamodzi amatchedwa epitaxial wafers. Mwa iwo, ndisilicon carbide epitaxialwosanjikiza amakula pa gawo lapansi lopangira silicon carbide kuti apeze silicon carbide homogeneous epitaxial wafer, yomwe imatha kupangidwanso kukhala zida zamagetsi monga Schottky diodes, MOSFETs, ndi IGBTs. Mwa iwo, omwe amagwiritsidwa ntchito kwambiri ndi gawo lapansi la 4H-SiC.
Popeza zipangizo zonse kwenikweni anazindikira pa epitaxy, khalidwe laepitaxyzimakhudza kwambiri ntchito ya chipangizocho, koma khalidwe la epitaxy limakhudzidwa ndi kukonza makristasi ndi magawo. Ili pakatikati pamakampani ndipo imagwira ntchito yofunika kwambiri pakukula kwamakampani.
Njira zazikulu zokonzekera zigawo za silicon carbide epitaxial ndi: njira ya kukula kwa evaporation; madzi gawo epitaxy (LPE); molecular beam epitaxy (MBE); Chemical vapor deposition (CVD).
Pakati pawo, chemical vapor deposition (CVD) ndiyo njira yotchuka kwambiri ya 4H-SiC homoepitaxial. 4-H-SiC-CVD epitaxy nthawi zambiri imagwiritsa ntchito zida za CVD, zomwe zingatsimikizire kupitiriza kwa epitaxial wosanjikiza 4H crystal SiC pansi pa kutentha kwakukulu kwa kukula.
Mu zida za CVD, gawo lapansi silingayikidwe mwachindunji pazitsulo kapena kungoyikidwa pa maziko a epitaxial deposition, chifukwa limaphatikizapo zinthu zosiyanasiyana monga njira yopita kwa gasi (yopingasa, yoyima), kutentha, kupanikizika, kukonza, ndi zowononga zogwa. Choncho, maziko amafunikira, ndiyeno gawo lapansi limayikidwa pa disk, ndiyeno epitaxial deposition ikuchitika pa gawo lapansi pogwiritsa ntchito teknoloji ya CVD. Maziko awa ndi SiC yokutidwa ndi graphite maziko.
Monga chigawo chapakati, graphite m'munsi ali ndi makhalidwe a mkulu enieni mphamvu ndi modulus yeniyeni, zabwino matenthedwe kukana mantha ndi dzimbiri kukana, koma pa ndondomeko kupanga graphite adzakhala dzimbiri ndi ufa chifukwa chotsalira mpweya zikuwononga ndi zitsulo organic. nkhani, ndipo moyo wautumiki wa maziko a graphite udzachepetsedwa kwambiri.
Pa nthawi yomweyi, ufa wa graphite umene wagwa udzaipitsa chip. Popanga ma silicon carbide epitaxial wafers, ndizovuta kukwaniritsa zomwe anthu amafunikira kwambiri pakugwiritsa ntchito zida za graphite, zomwe zimalepheretsa kukula kwake ndikugwiritsa ntchito kwake. Chifukwa chake, ukadaulo wokutira unayamba kuwuka.
2. Ubwino waKupaka kwa SiC
Zowonongeka zakuthupi ndi mankhwala a zokutira zimakhala ndi zofunikira zolimba za kutentha kwakukulu ndi kukana kwa dzimbiri, zomwe zimakhudza mwachindunji zokolola ndi moyo wa mankhwala. Zinthu za SiC zili ndi mphamvu zambiri, kuuma kwakukulu, kutsika kwamafuta owonjezera komanso kuwongolera kwamafuta abwino. Ndichinthu chofunikira kwambiri cha kutentha kwambiri komanso kutentha kwambiri kwa semiconductor. Amagwiritsidwa ntchito ku maziko a graphite. Ubwino wake ndi:
-SiC imalimbana ndi dzimbiri ndipo imatha kukulunga kwathunthu maziko a graphite, ndipo imakhala ndi kachulukidwe kabwino kuti isawonongeke ndi mpweya wowononga.
-SiC ili ndi matenthedwe apamwamba kwambiri komanso mphamvu zomangirira kwambiri ndi maziko a graphite, kuonetsetsa kuti zokutira sizikhala zophweka kugwa pambuyo pa maulendo angapo otentha kwambiri komanso otsika kwambiri.
-SiC ili ndi kukhazikika kwamankhwala abwino kuti ateteze zokutira kuti zisawonongeke mumlengalenga wotentha komanso wowononga.
Kuphatikiza apo, ng'anjo za epitaxial zazinthu zosiyanasiyana zimafuna ma tray a graphite okhala ndi zizindikiro zosiyanasiyana zogwirira ntchito. Kukula kwamafuta kofananira ndi zida za graphite kumafuna kusintha kutentha kwa ng'anjo ya epitaxial. Mwachitsanzo, kutentha kwa silicon carbide epitaxial kukula ndikwambiri, ndipo thireyi yokhala ndi matenthedwe ofananira ndi matenthedwe amafunikira. Kukula kwamafuta kowonjezera kwa SiC kuli pafupi kwambiri ndi graphite, ndikupangitsa kuti ikhale yoyenera ngati zinthu zomwe zimakonda kwambiri zokutira pamwamba pa maziko a graphite.
Zida za SiC zili ndi mitundu yosiyanasiyana ya kristalo, ndipo zofala kwambiri ndi 3C, 4H ndi 6H. Mitundu yosiyanasiyana ya kristalo ya SiC imakhala ndi ntchito zosiyanasiyana. Mwachitsanzo, 4H-SiC ikhoza kugwiritsidwa ntchito popanga zida zamphamvu kwambiri; 6H-SiC ndiyokhazikika kwambiri ndipo ingagwiritsidwe ntchito kupanga zipangizo za optoelectronic; 3C-SiC ikhoza kugwiritsidwa ntchito kupanga zigawo za GaN epitaxial ndikupanga zipangizo za SiC-GaN RF chifukwa cha mawonekedwe ake ofanana ndi GaN. 3C-SiC imatchedwanso β-SiC. Kugwiritsa ntchito β-SiC ndikofunikira ngati filimu yopyapyala komanso zokutira. Chifukwa chake, β-SiC pakadali pano ndiye chinthu chofunikira kwambiri pakuyala.
Zovala za SiC zimagwiritsidwa ntchito kwambiri popanga semiconductor. Amagwiritsidwa ntchito makamaka mu magawo, epitaxy, kufalikira kwa okosijeni, etching ndi ion implantation. Zomwe zimapangidwira ndi mankhwala a zokutira zimakhala ndi zofunikira kwambiri pa kutentha kwakukulu ndi kukana kwa dzimbiri, zomwe zimakhudza mwachindunji zokolola ndi moyo wa mankhwala. Chifukwa chake, kukonzekera kwa zokutira za SiC ndikofunikira.
Nthawi yotumiza: Jun-24-2024