Ukukhula kwe-SiC silicon carbide single crystal

Selokhu yatholakala, i-silicon carbide idonse ukunaka okusabalele. I-Silicon carbide yakhiwe ngesigamu sama-athomu e-Si nengxenye yama-athomu u-C, axhunywe ngamabhondi ahlangene ngamapheya e-electron abelana nge-sp3 hybrid orbitals. Engxenyeni eyisisekelo yesakhiwo sekristalu yayo eyodwa, ama-athomu amane e-Si ahlelwe ngesakhiwo esivamile se-tetrahedral, futhi i-athomu ye-C itholakala enkabeni ye-tetrahedron evamile. Ngokuphambene, i-athomu ye-Si ingabuye ithathwe njengesikhungo se-tetrahedron, ngaleyo ndlela yakhe i-SiC4 noma i-CSi4. Isakhiwo se-Tetrahedral. I-covalent bond ku-SiC i-ionic kakhulu, futhi amandla e-silicon-carbon bond aphezulu kakhulu, cishe i-4.47eV. Ngenxa yamandla amaphutha okunqwabelanisa aphansi, amakristalu e-silicon carbide akha kalula ama-polytypes ahlukahlukene phakathi nenqubo yokukhula. Kunama-polytypes aziwayo angaphezu kuka-200, angahlukaniswa ngezigaba ezintathu ezinkulu: i-cubic, i-hexagonal kanye ne-trigonal.

Njengamanje, izindlela eziyinhloko zokukhula zamakristalu e-SiC zifaka i-Physical Vapor Transport Method (indlela ye-PVT), I-High Temperature Chemical Vapor Deposition (indlela ye-HTCVD), Indlela Yesigaba Se-Liquid, njll. Phakathi kwazo, indlela ye-PVT ivuthiwe futhi ifaneleka kakhulu ezimbonini. ukukhiqizwa ngobuningi. .

Indlela ebizwa nge-PVT ibhekisela ekubekeni amakristalu embewu ye-SiC phezulu kwe-crucible, nokubeka i-SiC powder njengento eluhlaza ngaphansi kwe-crucible. Endaweni evaliwe yokushisa okuphezulu nokucindezela okuphansi, i-SiC powder sublimates futhi ikhuphukele phezulu ngaphansi kwesenzo se-gradient yokushisa kanye nomehluko wokuhlushwa. Indlela yokuyihambisa endaweni yekristalu yembewu bese iphinda icwebezelisa ngemva kokufinyelela esimweni esigcwele kakhulu. Le ndlela ingafinyelela ukukhula okulawulwayo kosayizi wekristalu ye-SiC namafomu athile ekristalu. .
Kodwa-ke, ukusebenzisa indlela ye-PVT ukukhulisa amakristalu e-SiC kudinga njalo ukugcina izimo ezifanele zokukhula phakathi nenqubo yokukhula yesikhathi eside, ngaphandle kwalokho kuzoholela ekuphazamisekeni kwe-lattice, ngaleyo ndlela kuthinte ikhwalithi ye-crystal. Kodwa-ke, ukukhula kwamakristalu e-SiC kuqedwa endaweni evaliwe. Zimbalwa izindlela zokuqapha ezisebenzayo kanye neziguquguqukayo eziningi, ngakho ukulawulwa kwenqubo kunzima.

Enkambweni yokukhulisa amakristalu e-SiC ngendlela ye-PVT, imodi yokukhula kokugeleza kwesinyathelo (Ukukhula Kwesinyathelo) kubhekwa njengendlela eyinhloko yokukhula okuzinzile kwefomu elilodwa le-crystal.
Ama-athomu e-Si ahwamukile kanye nama-athomu e-C azokhethwa ngokukhethekile nama-athomu angaphezulu kwekristalu endaweni ye-kink, lapho azohlangana khona futhi akhule, okwenza isinyathelo ngasinye sigeleze siye phambili ngokuhambisana. Lapho ububanzi besinyathelo endaweni yekristalu budlula kude indlela yamahhala ye-adatom, inani elikhulu lama-adatom lingase libe yi-agglomerate, futhi imodi yokukhula efana nesiqhingi enezinhlangothi ezimbili eyakhiwe izobhubhisa imodi yokukhula kwesinyathelo, okuholela ekulahlekelweni kwe-4H. ulwazi lwesakhiwo sekristalu, okuholela kumaphutha amaningi. Ngakho-ke, ukulungiswa kwemingcele yenqubo kufanele kufinyelele ukulawulwa kwesakhiwo sesinyathelo esiphezulu, ngaleyo ndlela kucindezela isizukulwane sezinkinga ze-polymorphic, ukufeza injongo yokuthola ifomu elilodwa le-crystal, futhi ekugcineni lilungiselele amakristalu aphezulu.

Njengendlela yokuqala yokukhula kwekristalu ye-SiC, indlela yokuthutha umhwamuko ongokoqobo njengamanje iyindlela yokukhula evamile yokukhulisa amakristalu e-SiC. Uma kuqhathaniswa nezinye izindlela, le ndlela inezidingo eziphansi zemishini yokukhula, inqubo yokukhula elula, ukulawuleka okuqinile, ucwaningo olunzulu lwentuthuko, futhi isivele isizuzile ukusetshenziswa kwezimboni. Inzuzo yendlela ye-HTCVD ukuthi ingakhula ama-wafers e-conductive (n, p) kanye ne-high-purity semi-insulating, futhi ingakwazi ukulawula ukugxila kwe-doping ukuze ukugxila kwenkampani yenethiwekhi ku-wafer kushintsheke phakathi kuka-3×1013~5×1019 /cm3. Okubi umkhawulo ophezulu wezobuchwepheshe kanye nesabelo semakethe esiphansi. Njengoba ubuchwepheshe bokukhula kwekristalu besigaba se-SiC buqhubeka nokuvuthwa, buzobonisa amandla amakhulu ekuthuthukiseni yonke imboni ye-SiC esikhathini esizayo futhi kungenzeka kube iphuzu elisha lokuthuthuka ekukhuleni kwekristalu ye-SiC.