Kusukela ekutholakaleni kwayo, i-silicon carbide idonsele ukunaka kabanzi. I-Silicon carbide yakhiwe ama-athomu e-Si ayingxenye kanye nama-athomu e-C ayingxenye, axhunywe ngama-covalent bonds ngokusebenzisa ama-electron pairs abelana ngama-orbital e-sp3 hybrid. Eyunithi eyisisekelo yesakhiwo sekristalu yayo eyodwa, ama-athomu amane e-Si ahlelwe ngesakhiwo se-tetrahedral esivamile, kanti i-athomu ye-C itholakala enkabeni ye-tetrahedron evamile. Ngokuphambene nalokho, i-athomu ye-Si ingabhekwa njengesikhungo se-tetrahedron, ngaleyo ndlela yakha i-SiC4 noma i-CSi4. Isakhiwo se-tetrahedral. Isibopho se-covalent ku-SiC sinamandla kakhulu, futhi amandla esibopho se-silicon-carbon aphezulu kakhulu, cishe angu-4.47eV. Ngenxa yamandla aphansi e-stacking fault, amakristalu e-silicon carbide akha kalula ama-polytype ahlukahlukene ngesikhathi senqubo yokukhula. Kunezinhlobo ezingaphezu kuka-200 zama-polytype ezaziwayo, ezingahlukaniswa ngezigaba ezintathu ezinkulu: i-cubic, i-hexagonal kanye ne-trigonal.
Njengamanje, izindlela eziyinhloko zokukhula kwamakristalu e-SiC zifaka phakathi i-Physical Vapor Transport Method (indlela ye-PVT), i-High Temperature Chemical Vapor Deposition (indlela ye-HTCVD), i-Liquid Phase Method, njll. Phakathi kwazo, indlela ye-PVT ivuthiwe kakhulu futhi ifaneleka kakhulu ekukhiqizweni kwezimboni.
Indlela ebizwa ngokuthi i-PVT ibhekisela ekubekeni amakristalu embewu ye-SiC phezulu kwe-crucible, bese kubekwa i-SiC powder njengezinto zokusetshenziswa phansi kwe-crucible. Endaweni evaliwe yokushisa okuphezulu kanye nokucindezela okuphansi, i-SiC powder iyacwilisa futhi iqhubekele phezulu ngaphansi kwesenzo sokwehluka kokushisa kanye nokuhlushwa. Indlela yokuyithutha iye eduze kwe-seed crystal bese uyiphinda uyifake kabusha ngemva kokufinyelela esimweni esigcwele kakhulu. Le ndlela ingafinyelela ukukhula okulawulwayo kobukhulu be-SiC crystal kanye nezinhlobo ezithile ze-crystal.
Kodwa-ke, ukusebenzisa indlela ye-PVT ukukhulisa amakristalu e-SiC kudinga ukugcina izimo zokukhula ezifanele njalo phakathi nenqubo yokukhula yesikhathi eside, ngaphandle kwalokho kuzoholela ekuphazamisekeni kwe-lattice, ngaleyo ndlela kuthinte ikhwalithi yekristalu. Kodwa-ke, ukukhula kwamakristalu e-SiC kuqedwa endaweni evaliwe. Zimbalwa izindlela zokuqapha ezisebenzayo kanye neziguquguquko eziningi, ngakho-ke ukulawula inqubo kunzima.
Enkambisweni yokukhulisa amakristalu e-SiC ngendlela ye-PVT, imodi yokukhula kokugeleza kwesinyathelo (Ukukhula Kokugeleza Kwesinyathelo) ibhekwa njengendlela eyinhloko yokukhula okuzinzile kwesimo sekristalu esisodwa.
Ama-athomu e-Si aphefumulayo nama-athomu e-C azonamathelana nama-athomu obuso bekristalu endaweni yokugoba, lapho azokhula khona futhi akhule, okwenza isinyathelo ngasinye sigeleze phambili ngokuhambisana. Lapho ububanzi besinyathelo ebusweni bekristalu budlula kakhulu indlela engenakusasazwa yama-adatomu, inani elikhulu lama-adatomu lingase lihlangane, futhi imodi yokukhula efana nesiqhingi enezinhlangothi ezimbili eyakhiwe izobhubhisa imodi yokukhula kokugeleza kwesinyathelo, okuholela ekulahlekelweni kolwazi lwesakhiwo sekristalu esingu-4H, okuholela emaphutheni amaningi. Ngakho-ke, ukulungiswa kwamapharamitha enqubo kumele kufinyelele ekulawulweni kwesakhiwo sesinyathelo sobuso, ngaleyo ndlela kucindezelwe ukukhiqizwa kwamaphutha e-polymorphic, kufezwe inhloso yokuthola ifomu elilodwa lekristalu, futhi ekugcineni kulungiselelwe amakristalu asezingeni eliphezulu.
Njengendlela yokuqala yokukhula kwekristalu ye-SiC ethuthukisiwe, indlela yokuthutha umhwamuko ongokoqobo njengamanje iyindlela yokukhula evame kakhulu yokutshala amakristalu e-SiC. Uma kuqhathaniswa nezinye izindlela, le ndlela inezidingo eziphansi zemishini yokukhula, inqubo yokukhula elula, ukulawula okuqinile, ucwaningo oluphelele lwentuthuko, futhi isivele ifinyelele ukusetshenziswa kwezimboni. Inzuzo yendlela ye-HTCVD ukuthi ingakhula ama-wafer asebenzisa amandla (n, p) kanye nama-wafer ahlanzekile kakhulu, futhi ingalawula ukugcwala kwe-doping ukuze ukugcwala komthwali ku-wafer kulungiswe phakathi kuka-3×1013~5×1019/cm3. Okubi ngumkhawulo wobuchwepheshe ophezulu kanye nesabelo semakethe esiphansi. Njengoba ubuchwepheshe bokukhula kwekristalu ye-SiC yesigaba soketshezi buqhubeka nokuvuthwa, buzobonisa amandla amakhulu ekuthuthukiseni yonke imboni ye-SiC esikhathini esizayo futhi cishe buzoba yiphuzu elisha lokukhula kwekristalu ye-SiC.
Isikhathi sokuthunyelwe: Ephreli-16-2024