Chiyambireni kupezeka kwake, silicon carbide yakopa chidwi chambiri. Silicon carbide imapangidwa ndi theka la ma atomu a Si ndi theka la C maatomu, omwe amalumikizidwa ndi ma covalent bond kudzera ma electron awiriawiri akugawana sp3 hybrid orbitals. Mu gawo loyambira la kristalo wake umodzi, ma atomu anayi a Si amapangidwa mokhazikika, ndipo C atomu ili pakatikati pa tetrahedron yokhazikika. Mosiyana ndi izi, atomu ya Si imathanso kuwonedwa ngati pakati pa tetrahedron, potero kupanga SiC4 kapena CSi4. Tetrahedral kapangidwe. Chomangira chokhazikika mu SiC ndi ionic kwambiri, ndipo mphamvu ya silicon-carbon bond ndi yokwera kwambiri, pafupifupi 4.47eV. Chifukwa cha kuchepa kwamphamvu kwamphamvu, makristalo a silicon carbide amapanga ma polytypes osiyanasiyana panthawi yakukula. Pali mitundu yopitilira 200 yodziwika bwino, yomwe imatha kugawidwa m'magulu atatu akuluakulu: cubic, hexagonal ndi trigonal.
Pakali pano, njira zazikulu za kukula kwa makristasi a SiC zimaphatikizapo Physical Vapor Transport Method (PVT njira), High Temperature Chemical Vapor Deposition (njira ya HTCVD), Njira ya Liquid Phase, ndi zina zotero. Pakati pawo, njira ya PVT ndiyokhwima kwambiri komanso yoyenera mafakitale kupanga zochuluka. .
Njira yotchedwa PVT imatanthawuza kuyika makhiristo ambewu ya SiC pamwamba pa crucible, ndikuyika ufa wa SiC ngati zopangira pansi pa crucible. M'malo otsekedwa ndi kutentha kwakukulu komanso kutsika kwapansi, ufa wa SiC umatsika ndikukwera mmwamba pansi pa kutentha kwa kutentha ndi kusiyana kwa ndende. Njira yotumizira kufupi ndi kristalo ya mbewu ndikuyiyikanso pambuyo pofika pamtunda wapamwamba. Njirayi imatha kukwaniritsa kukula kosinthika kwa kukula kwa kristalo wa SiC ndi mitundu yeniyeni ya kristalo. .
Komabe, kugwiritsa ntchito njira ya PVT kuti ikule makhiristo a SiC kumafuna kuti nthawi zonse mukhale ndi kukula koyenera panthawi ya kukula kwa nthawi yaitali, mwinamwake zidzayambitsa vuto la lattice, motero zimakhudza ubwino wa kristalo. Komabe, kukula kwa makristasi a SiC kumatsirizidwa pamalo otsekedwa. Pali njira zochepa zowunikira komanso zosinthika zambiri, kotero kuwongolera njira kumakhala kovuta.
Pogwiritsa ntchito kukula kwa makristasi a SiC ndi njira ya PVT, njira ya kukula kwa sitepe (Step Flow Growth) imatengedwa kuti ndiyo njira yaikulu ya kukula kokhazikika kwa mawonekedwe amodzi a kristalo.
Ma atomu a Si okhala ndi mpweya ndi ma atomu a C amalumikizana makamaka ndi maatomu a crystal pamwamba pa kink point, pomwe adzakhazikika ndikukula, zomwe zimapangitsa kuti gawo lililonse liziyenda molumikizana. Pamene sitepe m'lifupi pa galasi pamwamba kuposa mayamwidwe ufulu njira ya adatoms, chiwerengero chachikulu cha adatoms mwina agglomerate, ndi awiri azithunzithunzi chilumba ngati kukula akafuna anapanga adzawononga sitepe otaya kukula akafuna, chifukwa imfa ya 4H. chidziwitso cha kapangidwe ka kristalo, zomwe zimapangitsa kuti pakhale zolakwika zingapo. Choncho, kusintha magawo ndondomeko ayenera kukwaniritsa ulamuliro wa pamwamba sitepe dongosolo, potero kupondereza m'badwo wa zofooka polymorphic, kukwaniritsa cholinga cha kupeza limodzi kristalo mawonekedwe, ndipo potsirizira pake kukonzekera makhiristo apamwamba.
Monga njira yoyambilira ya SiC crystal kukula, njira yoyendetsera nthunzi yakuthupi ndiyo njira yokulirapo yokulira makhiristo a SiC. Poyerekeza ndi njira zina, njirayi ili ndi zofunikira zochepa pazida zokulirapo, njira yosavuta yakukula, kuwongolera mwamphamvu, kafukufuku wokwanira wachitukuko, ndipo yakwaniritsa kale ntchito zamafakitale. Ubwino wa HTCVD njira ndi kuti akhoza kukula conductive (n, p) ndi mkulu-chiyero theka-kuteteza zopyapyala, ndipo akhoza kulamulira doping ndende kuti chonyamulira ndende mu yopyapyala ndi chosinthika pakati 3 × 1013 ~ 5 × 1019 /cm3. Zoyipa zake ndizolowera luso lapamwamba komanso gawo lotsika pamsika. Pamene luso la kukula kwa galasi la SiC lamadzimadzi likupitirira kukula, liwonetsa kuthekera kwakukulu pakupititsa patsogolo makampani onse a SiC m'tsogolomu ndipo ndikuyenera kukhala malo atsopano opambana a SiC crystal kukula.
Nthawi yotumiza: Apr-16-2024