Ukusukela oko yafunyaniswayo, i-silicon carbide itsale ingqalelo ebanzi. I-Silicon carbide yenziwe ngesiqingatha se-athom ze-Si kunye nesiqingatha se-athom ze-C, ezidityaniswe ngamabhondi adibeneyo ngokusebenzisa izibini ze-electron ukwabelana nge-sp3 hybrid orbitals. Kwiyunithi yesiseko yesiseko sekristale yayo enye, iiathom ezine zeSi zicwangciswe kwisakhiwo esiqhelekileyo se-tetrahedral, kwaye i-athomu ye-C ibekwe kumbindi wetetrahedron eqhelekileyo. Ngokuchaseneyo, i-atom ye-Si inokuthi ithathwe njengendawo ye-tetrahedron, ngokwenza oko i-SiC4 okanye i-CSi4. Ubume beTetrahedral. I-covalent bond kwi-SiC i-ionic kakhulu, kwaye i-silicon-carbon bond bond energy iphezulu kakhulu, malunga ne-4.47eV. Ngenxa yamandla esiphoso esisezantsi, iikristale ze-silicon carbide zenza ngokulula iipolytypes ezahlukeneyo ngexesha lenkqubo yokukhula. Kukho ngaphezu kwe-200 iipolytypes ezaziwayo, ezinokuthi zohlulwe zibe ziindidi ezintathu eziphambili: i-cubic, i-hexagonal kunye ne-trigonal.
Okwangoku, iindlela eziphambili zokukhula kweekristale ze-SiC ziquka i-Physical Vapor Transport Method (indlela ye-PVT), i-High Temperature Chemical Vapor Deposition (indlela ye-HTCVD), i-Liquid Phase Method, njl. imveliso enkulu.
Indlela ebizwa ngokuba yi-PVT ibhekisela ekubekeni i-crystals yembewu ye-SiC phezulu kwe-crucible, kwaye ibeke i-SiC powder njengento eluhlaza phantsi kwe-crucible. Kwindawo evaliweyo yokushisa okuphezulu kunye noxinzelelo oluphantsi, i-SiC powder i-sublimates kwaye ihambela phezulu phantsi kwesenzo se-gradient yeqondo lokushisa kunye nokwahlukana koxinzelelo. Indlela yokuyihambisa kwindawo ekufutshane nekristale yembewu kwaye emva koko uyibuyisele emva kokufikelela kwimo ephezulu. Le ndlela inokufezekisa ukukhula okulawulwayo kobungakanani bekristale yeSiC kunye neefom ezithile zekristale.
Nangona kunjalo, ukusebenzisa indlela ye-PVT yokukhulisa i-crystals ye-SiC ifuna ukuhlala igcina iimeko ezifanelekileyo zokukhula ngexesha lenkqubo yokukhula kwexesha elide, ngaphandle koko kuya kubangela ukuphazamiseka kwe-lattice, ngaloo ndlela kuchaphazela umgangatho we-crystal. Nangona kunjalo, ukukhula kweekristale ze-SiC kugqitywe kwindawo evaliweyo. Zimbalwa iindlela zokubeka iliso ezisebenzayo kunye neenguqu ezininzi, ngoko ke ulawulo lwenkqubo lunzima.
Kwinkqubo yokukhulisa i-crystals ye-SiC ngendlela ye-PVT, imowudi yokukhula kwesinyathelo (i-Step Flow Growth) ithathwa njengeyona ndlela iphambili yokukhula okuzinzile kwefom ye-crystal eyodwa.
I-athomu ye-Si enomphunga kunye ne-athomu ye-C iya kudibanisa ngokukhethiweyo kunye ne-athomu ye-crystal surface kwi-kink point, apho ziya ku-nucleate kwaye zikhule, zibangele ukuba inyathelo ngalinye liqhube phambili ngokuhambelanayo. Xa ububanzi benyathelo kumphezulu wekristale budlula kude ukusasazwa kwendlela esimahla yeeadatom, inani elikhulu le-adatom linokuthi lidibanise, kwaye imowudi yokukhula efana nesiqithi-ezimbini-ezifana nesiqithi ziya kutshabalalisa imo yokukhula kwenyathelo, okukhokelela ekulahlekeni kwe-4H. ulwazi lwesakhiwo sekristale, okukhokelela kwiziphene ezininzi. Ngoko ke, ukulungiswa kweeparamitha zenkqubo kufuneka kufezekise ukulawulwa kwesakhiwo sesinyathelo somhlaba, ngaloo ndlela kucinezela isizukulwana seziphene ze-polymorphic, ukufezekisa injongo yokufumana ifom ye-crystal eyodwa, kwaye ekugqibeleni ilungiselele iikristali eziphezulu.
Njengeyona ndlela yakuqala yokukhula kwekristale ye-SiC, indlela yokuthutha umphunga womzimba ngoku yeyona ndlela iphambili yokukhula yokukhulisa iikristale ze-SiC. Xa kuthelekiswa nezinye iindlela, le ndlela ineemfuno ezisezantsi zezixhobo zokukhula, inkqubo yokukhula elula, ukulawulwa okuqinileyo, uphando lophuhliso olucokisekileyo, kwaye sele lufezekise isicelo soshishino. Inzuzo yendlela ye-HTCVD kukuba inokukhula i-conductive (n, p) kunye ne-high-purity semi-insulating wafers, kwaye inokulawula i-doping concentration ukuze i-concentration carrier in the wafer ilungelelaniswe phakathi kwe-3 × 1013 ~ 5 × 1019 /cm3. Izinto ezingeloncedo ngumgangatho ophezulu wobugcisa kunye nesabelo semarike esisezantsi. Njengoko itekhnoloji yokukhula kwekristale yesigaba se-SiC iqhubeka nokukhula, iya kubonisa amandla amakhulu ekuqhubeleni phambili ishishini le-SiC lonke kwixesha elizayo kwaye inokuba yindawo entsha yokuphumelela ekukhuleni kwekristale ye-SiC.
Ixesha lokuposa: Apr-16-2024