Umgaqo weNdlela yePVT Ukukhula kweCrystal yeSilicon Carbide (SiC)

Indlela ye-PVT, egama layo lipheleleyo yi-Physical Vapor Transportation, yindlela eqhelekileyo yokukhulisa i-silicon carbide (I-SiCiikristale eziphantsi kobushushu obuphezulu kunye noxinzelelo oluphezulu. Umgaqo wayo osisiseko kukufudumala i-silicon carbide powder ukuya kwi-sublimation kubushushu obungaphezulu kwe-2300℃ nakwindawo enoxinzelelo oluphantsi kufutshane ne-vacuum, okwenza igesi yokusabela equlethe izinto zegesi ezifana ne-Si, i-Si2C, kunye ne-SiC2. Ngenxa yoxinzelelo oluhlukeneyo lwe-gas-phase lwe-Si kunye ne-C components ezenziwe yi-solid-phase sublimation reaction, umlinganiselo we-Si/C stoichiometric uyahluka ngokusasazwa kwentsimi yobushushu. Ke ngoko, kuyimfuneko ukulawula ukusasazwa kunye nokuthuthwa kwezixhobo ze-gas-phase ukuqinisekisa ukuba zifikelela kwiindawo ezithile ze-crystallization kwigumbi lokukhula.

Ukuthintela i-gas-phase crystallization engacwangciswanga ukuba yenze i-polycrystalline silicon carbide, ii-silicon carbide seed crystals zibekwe phezulu kwigumbi lokukhula. Phantsi kwe-gas-phase supersaturation, ii-gas-phase components ziya kuhlala phezu komphezulu we-seed crystal ukuze zenze ii-silicon carbide single crystals. Yonke inkqubo yokusabela yenzeka kwigumbi lokukhula elivaliweyo, apho zonke iiparameter zenkqubo yokusabela zidityaniswe. Nakuphi na ukuguquguquka kwiimeko zokukhula kuya kuchaphazela ukuzinza kokukhula kwe-single crystal.

Ukongeza, izakhiwo ezahlukeneyo ezixineneyo zeekristale ze-silicon carbide single ngokwendlela ezisebenza ngayo kwikristale zikhokelela kwiindlela ezahlukeneyo zokunxibelelana kunye neendlela zokubopha iathomu, ngaloo ndlela zenze ii-isomers ze-silicon carbide ezingaphezu kwama-200 zekristale. Umqobo wokuguqulwa kwamandla phakathi kweefom zekristale ezahlukeneyo uphantsi kakhulu, ngoko ke utshintsho lwefom yekristale lunokwenzeka kakhulu kwinkqubo yokukhula kwekristale enye ye-PVT, nto leyo ekhokelela kwiifom zekristale ezijoliswe kuzo ezingalungelelaniswanga kunye neziphene ezahlukeneyo zekristale. Ke ngoko, kuyimfuneko ukusebenzisa izixhobo zokuhlola ezizinikeleyo ukufumanisa ifom yekristale kunye neziphene ezahlukeneyo ze-ingot yekristale.

Inkqubo yokulungiselela i-silicon carbide ineemfuno eziphezulu kakhulu, ikakhulu ezibonakala kwezi zinto zilandelayo:

• Kukho ukungcola okuninzi kwendalo kwinkqubo yokwenziwa kwe-silicon carbide powder, okwenza kube nzima ukufumana i-high-purity powder. Impendulo engaphelelanga phakathi kwe-silicon powder kunye ne-carbon powder njengomthombo wokusabela inokubangela ukungalingani kwi-Si/C ratio. Uhlobo lwekristale kunye nobukhulu bee-particle ze-silicon carbide powder emva kokwenziwa kunzima ukulawula.
• Phantsi kweemeko zobushushu obuphezulu obungaphezulu kwama-2300℃ kwaye kufutshane ne-vacuum, i-silicon carbide idlula kwinkqubo yokuguqulwa kwe-"solid-gas-solid" kunye nenkqubo yokuphinda i-crystallization kwigumbi le-graphite elivaliweyo. Le nkqubo inomjikelo wokukhula omde, kunzima ukuyilawula, kwaye ithambekele kwiimpazamo ezifana nee-microtubules kunye ne-inclusions.
• I-silicon carbide iquka iintlobo zekristale ezahlukeneyo ezingaphezu kwama-200, kodwa imveliso idla ngokufuna uhlobo olunye lwekristale. Ngexesha lenkqubo yokukhula, utshintsho lwefomu yekristale lunokwenzeka, nto leyo ebangela iziphene zokufakwa kweentlobo ezininzi. Ngexesha lenkqubo yokulungiselela, kunzima ukulawula ngokuzinzileyo uhlobo olunye lwekristale, kwaye umqobo wokuguqulwa kwamandla phakathi kweentlobo ezahlukeneyo zekristale uphantsi kakhulu, nto leyo enyusa ubunzima bolawulo. Ulawulo lweeparameter kunye nophando oluhambelanayo ngeli xesha lufuna iindleko ezinkulu ze-R&D, nto leyo ekwayenye yezizathu zeendleko eziphezulu ze-silicon carbide ehambelanayo.