Kukula kwa PVT Silicon Carbide Crystal: Zipangizo Zapamwamba Zopangira Makristalo a SiC Okhala ndi Zokolola Zambiri

Pamene makampani opanga magetsi padziko lonse lapansi akufulumizitsa kugwiritsa ntchito zipangizo za silicon carbide (SiC) kuti zigwiritsidwe ntchito m'magalimoto amagetsi, machitidwe amagetsi obwezerezedwanso, ndi mafakitale amphamvu kwambiri, kufunikira kwa zinthu za SiC zazikulu komanso zopanda vuto kukupitiliza kukula. Ukadaulo wa kukula kwa kristalo wa PVT silicon carbide ndiye maziko a kusinthaku kopanga ndipo ndiye njira yayikulu yopangira makristalo apamwamba a 4H-SiC amodzi pazida zamagetsi zamagetsi zam'badwo wotsatira.

Mavuto Aakulu Omwe Akukumana Ndi Machitidwe Amakono Okulitsa Makristalo a PVT Silicon Carbide

Ngakhale kuti pakhala zaka zambiri za chitukuko, kukula kwa makristalo a PVT silicon carbide kukadali njira yovuta kwambiri popanga ma semiconductor. Kukula kwa makristalo kumachitika pamalo otsekedwa, otentha kwambiri opitilira 2000°C, pomwe zinthu zoyambira za silicon carbide zimasungunuka ndikubwereranso ku makristalo a mbewu pansi pa kutentha kolamulidwa bwino. Muzochitika zovuta kwambiri zotere, ngakhale kusinthasintha pang'ono pakugawa kutentha, kayendedwe ka nthunzi, kapena kuyera kwa zinthu kungakhudze kwambiri mawonekedwe a makristalo, kukhazikika kwa polymorph, ndi kapangidwe ka zolakwika.

Chimodzi mwa zovuta zazikulu pakukula kwa makristalo a PVT SiC ndi kukhazikika kwa nthawi yayitali kwa mphamvu ya kutentha. Zigawo zachikhalidwe za graphite nthawi zonse zimakumana ndi nthunzi zomwe zimakhala ndi silicon, monga Si, Si₂C, ndi SiC₂. Pakagwiritsidwa ntchito nthawi yayitali, nthunzi izi zimalumikizana ndi pamwamba pa graphite, zomwe zimapangitsa kuti zinthu ziwonongeke pang'onopang'ono, kusintha kwa mawonekedwe, komanso kusokonekera kwa kutentha komwe kwapangidwa. Pamene mawonekedwe a malo otentha akusintha, zimakhala zovuta kwambiri kuwongolera zinthu zomwe zili pamwamba pa malo okulira, zomwe nthawi zambiri zimayambitsa kukula kosakhazikika kwa makristalo, kuchepa kwa kukula, komanso kuchuluka kwa zolakwika.

Kuyera kwa zinthu ndi chinthu chofunikira kwambiri choletsa. Kuchuluka kwa nayitrogeni, boron, aluminiyamu, titaniyamu, ndi zina zodetsedwa zachitsulo zomwe zimapezeka muzinthu zachikhalidwe zotentha zimafalikira mu gawo la nthunzi panthawi yogwira ntchito yotentha kwambiri. Zodetsedwa izi zikalowa mu kristalo yomwe ikukula, zimasintha kuchuluka kwa chonyamulira, kukana, ndi khalidwe lobwezera mkati mwa lattice ya 4H-SiC. Chofunika kwambiri, zochitika za nucleation zoyendetsedwa ndi kuipitsidwa zimathandizira kupangidwa kwa ma microtubes, basal plane dislocations (BPDs), screw-type dislocations (TSDs), ndi zolakwika zina za kapangidwe kake, zomwe zimakhudza mwachindunji kuchuluka kwa wafer ndi kudalirika kwa zida zotsika.

Pamene opanga silicon carbide (SiC) akusintha kuchoka pa kupanga ma wafer a mainchesi 6 kupita ku kupanga ma wafer a mainchesi 8, zofunikira kuti malo otenthetsera akhale olimba nazonso zawonjezeka kwambiri. Ma crystal diameter akuluakulu amafunika nthawi yayitali yokulira, kutentha kofanana kwa radial, komanso kuwongolera bwino kutentha. Makina otenthetsera achikhalidwe omwe amagwiritsa ntchito graphite nthawi zambiri amavutika kusunga kukhazikika komwe kumafunikira kuti ma crystal akule kwambiri, zomwe zimapangitsa kuti ndalama zogwirira ntchito zikhale zokwera komanso kuti ntchito yopangira ikhale yotsika.

Zipangizo Zapamwamba Zotenthetsera za PVT Silicon Carbide Crystal Growth

1. Zophimba za CVD TaC kuti Zikhale Zolimba Kwambiri pa Kutentha

Pofuna kuthana ndi mavutowa, ukadaulo wapamwamba wamagetsi otentha wakhala wofunikira kwambiri pakukula kwamakono kwa PVT silicon carbide crystal. Chimodzi mwa zinthu zotsogola kwambiri m'derali ndi kuyambitsa zokutira za chemical vapor deposition (CVD) tantalum carbide (TaC). Ndi malo osungunuka pafupifupi 3880°C komanso kukana bwino malo okhala ndi nthunzi wolemera mu silicon, TaC imagwira ntchito ngati chotchinga chofalikira pakati pa mpweya wochita zinthu mopupuluma ndi zinthu za graphite. Zophimba za TaC zimaletsa kugwiritsidwa ntchito kwa graphite ndikusunga kukhazikika kwa geometric panthawi yayitali yokulira, motero zimathandiza kusunga kufanana kwa mphamvu yamagetsi ndikuthandizira kukula kwa kristalo kokhazikika.

2. Chakudya Chapamwamba Choyera cha 7N Silicon Carbide Chochepetsa Zilema

Kupita patsogolo kwina kwakukulu ndikugwiritsa ntchito zinthu zoyambira za SiC zoyera kwambiri zomwe zimapangidwa kudzera mu chemical vapor deposition (CVD). Poyerekeza ndi chakudya chachikhalidwe cha Acheson-process, ufa wa SiC wokonzedwa ndi CVD uli ndi milingo yotsika kwambiri ya nayitrogeni ndi zitsulo. Ndi chiyero chofika pa 7N (99.99999%), izi zimathandiza kuwongolera bwino kapangidwe ka nthunzi panthawi ya sublimation, kuchepetsa mwayi wophatikizidwa ndi kuipitsidwa pomwe kumawonjezera khalidwe la kristalo ndi magwiridwe antchito amagetsi. Zinthu zoyera kwambirizi zikudziwika kwambiri ngati chofunikira kwambiri popanga zinthu zotsika zomwe zimagwiritsidwa ntchito muzipangizo za SiC zapamwamba komanso zamagalimoto.

3. Kapangidwe ka Graphite Yopangidwa ndi Microporous

Kukonza bwino malo otenthetsera kumalimbikitsidwanso ndi kapangidwe ka graphite kakang'ono kopangidwa mosamala komwe kamapangidwa kuti kayendetse kutentha ndi mpweya m'malo otenthetsera. Mwa kuwongolera bwino kugawa kwa porosity ndi kutentha, zigawozi zimathandiza kupanga kutentha kofanana komanso kuchepetsa kusokonezeka kwa convective. Zotsatira zake, ma ingot akuluakulu a silicon carbide amawonetsa malo okhazikika okulirapo, kuchepetsa kupsinjika kwa kutentha, komanso kukonza bwino kapangidwe kake.

4. Gawo Loteteza la Pyrolytic Carbon (PYC)

Kuphatikiza pa ukadaulo uwu, chophimba cha dense pyrolytic carbon (PYC) chimalepheretsanso kupanga tinthu tating'onoting'ono ndi kuyamwa mpweya. Kapangidwe kake ka kaboni kokonzedwa bwino kamapanga malo opanda ma pore, kuchepetsa magwero a kuipitsidwa mkati mwa chipinda chokulirapo pomwe kumawonjezera kulimba kwa gawolo panthawi yobwerezabwereza kutentha. Izi zimathandiza mwachindunji kuchepetsa kuchuluka kwa zolakwika zomwe zimachitika komanso kukonza kubwerezabwereza kwa njira.

Kusintha Koyenera kwa Silicon Carbide Crystal Growth Performance

Zotsatira zophatikizana za ukadaulo wapamwamba uwu zapangitsa kuti pakhale kusintha koyezeka pakupanga zinthu zofunika kwambiri. Dongosolo lotenthetsera lokonzedwa bwino latsimikiziridwa kuti limawonjezera kukula kwa makristalo ndi 15-20%, kusunga kukhazikika kwa zokolola za wafer pamwamba pa 90%, kukulitsa nthawi yokonza kuyambira miyezi 3 mpaka 6, ndikuchepetsa ndalama zogwirira ntchito ndi pafupifupi 40%. Chofunika kwambiri, kusinthaku kumathandizira kuchuluka kwa zolakwika pansi pa 0.05 defects/cm², motero kumathandiza kupanga zinthu zapamwamba zoyenera kugwiritsidwa ntchito pamagetsi ndi mafakitale.

Pamene kufunikira kwa zida za silicon carbide padziko lonse lapansi kukupitilira kukula, mwayi wopikisana wa opanga zinthu za SiC substrate umadalira kwambiri luso lawo lolamulira khalidwe la kristalo, kugwiritsa ntchito kwambiri reactor, ndikuchepetsa kusinthasintha kwa kupanga. Potengera izi, zipangizo zamakono zotenthetsera—kuphatikizapo zigawo za graphite zophimbidwa ndi TaC, chakudya cha SiC choyera kwambiri, kapangidwe ka graphite, ndi zigawo zoteteza kaboni za pyrolytic—zakhala ukadaulo wofunikira pakukula kwa makristasi a silicon carbide a m'badwo wotsatira a PVT.

Poganizira zamtsogolo, kupitiriza kupanga zatsopano muukadaulo wamagetsi otentha kudzatenga gawo lalikulu pakukwaniritsa kukula kwakukulu kwa ma wafer, kupanga kwakukulu, komanso kuchepa kwa zilema. Kwa opanga omwe adzipereka kupanga ma wafer a SiC omwe amakula komanso otsika mtengo, kukonza magetsi otentha sikulinso chinthu chachiwiri chomwe chimaganiziridwa koma chofunikira kwambiri kuti asunge mpikisano wanthawi yayitali pamsika wa semiconductor womwe ukukula mwachangu womwe ukukula mwachangu.

Mafunso Ofunsidwa Kawirikawiri Zokhudza Kukula kwa PVT Silicon Carbide Crystal

1. Kodi PVT Silicon Carbide Crystal Growth ndi chiyani, ndipo n’chifukwa chiyani ndiyo njira yabwino kwambiri yopangira zinthu za SiC?

Physical Npor Transport (PVT) pakadali pano ndi ukadaulo wodziwika bwino kwambiri wopanga zinthu zapamwamba za silicon carbide. Munjira imeneyi, zinthu zoyambira za SiC zoyera kwambiri zimayikidwa pansi pa kutentha komwe nthawi zambiri kumapitirira 2000°C ndikunyamulidwa kudzera mu nthunzi yolamulidwa isanakhazikitsidwenso pa kristalo ya mbewu.

Poyerekeza ndi njira zina zokulira makristalo, PVT imapereka kuthekera kwakukulu kopangira makristalo akuluakulu a 4H-SiC pomwe ikusunga khalidwe lovomerezeka la makristalo komanso ndalama zopangira. Pamene makampani akusintha kupita ku ma wafer a 200 mm (8-inch), kusintha kosalekeza pakupanga malo otentha a PVT, kuwongolera mayendedwe a nthunzi, ndi kuyera kwa zinthu kumakhalabe kofunikira kuti pakhale kupanga mafakitale kopindulitsa kwambiri.

2. Ndi mavuto otani omwe amabuka mukasintha kuchoka pa kupanga ma wafer a SiC a mainchesi 6 kupita ku 8 mainchesi?

Kusintha kuchokera ku ma wafer a SiC a 150 mm (6-inch) kupita ku 200 mm (8-inch) ndi chimodzi mwa zinthu zofunika kwambiri pamakampani opanga ma semiconductor a wide-bandgap. Komabe, ma crystal diameter akuluakulu amabweretsa mavuto akuluakulu aukadaulo.

Kutentha kwa kristalo kumawonjezeka kwambiri, zomwe zimafuna nthawi yayitali yokulira komanso kuwongolera kwambiri kutentha kwa radial. Kusagwirizana pang'ono kwa kutentha komwe kungavomerezedwe m'makristalo ang'onoang'ono kumatha kukhala magwero akuluakulu a kupsinjika, ming'alu, ndi kufalikira kwa zolakwika m'mabolo akuluakulu.

Chifukwa chake, kupanga kwa SiC ya mainchesi 8 kumafuna zipangizo zamakono zotenthetsera, zotetezera kutentha bwino, zokutira zapamwamba, ndi mapangidwe abwino kwambiri a uvuni kuti zinthu zizikhala zokhazikika nthawi yonse yokulira.

3. Kodi chophimba cha TaC chimathandiza bwanji kukula kwa PVT Silicon Carbide Crystal Growth?

Tantalum carbide (TaC) ndi imodzi mwa zipangizo zadothi zokhazikika kwambiri zomwe zimapezeka m'malo okulirapo a PVT. Popeza kutentha kwake kumafika pa 3880°C, zokutira za TaC zimapereka kukana kwabwino kwambiri motsutsana ndi nthunzi yochuluka ya silicon yomwe imapangidwa panthawi ya SiC sublimation.

Ikagwiritsidwa ntchito ku zigawo za graphite kudzera mu Chemical Npor Deposition (CVD), TaC imagwira ntchito ngati chotchinga chomwe chimaletsa kuwonongeka kwa mankhwala, imachepetsa kupanga tinthu tating'onoting'ono, ndikusunga mawonekedwe oyambira a kapangidwe ka matenthedwe.

Kusunga kukhazikika kwa magawo nthawi yonse yokulira kumathandiza kukhazikika kwa kayendedwe ka nthunzi ndi kutentha, zomwe zimathandiza mwachindunji kuti kukula kwa makristalo kukhale kolimba komanso kuchepetsa kuchuluka kwa zolakwika zomwe zimachitika.