Kwinkqubo yokukhula kwe-silicon carbide single crystal, ukuthuthwa komphunga ngokwasemzimbeni yindlela ephambili yangoku yophuhliso lwemizi-mveliso. Kwindlela yokukhula ye-PVT,umgubo we-silicon carbideinempembelelo enkulu kwinkqubo yokukhula. Zonke iiparameter zeumgubo we-silicon carbidezichaphazela ngokuthe ngqo umgangatho wokukhula kwekristale enye kunye neempawu zombane. Kwizicelo zangoku zoshishino, ezisetyenziswa rhoqoumgubo we-silicon carbideInkqubo yokwenziwa yindlela yokwenziwa yokwenziwa kobushushu obuphezulu eyazisasaza ngokwayo.
Indlela yokwenza izinto ezizisasaza ngokwazo isebenzisa ubushushu obuphezulu ukunika ii-reactants ubushushu bokuqala ukuqala ii-chemical reactions, ize isebenzise ubushushu bayo be-chemical reaction ukuvumela izinto ezingaphendulwanga ukuba ziqhubeke nokugqiba i-chemical reaction. Nangona kunjalo, ekubeni i-chemical reaction ye-Si kunye ne-C ikhupha ubushushu obuncinci, ezinye ii-reactants kufuneka zongezwe ukuze kugcinwe i-reaction. Ke ngoko, iingcali ezininzi zicebise indlela yokwenza izinto ezizisasaza ngokwazo ephuculweyo ngale ndlela, zizisa i-activator. Indlela yokwenza izinto ezizisasaza ngokwazo kulula ukuyisebenzisa, kwaye iiparameter ezahlukeneyo zokwenziwa kulula ukuzilawula ngokuzinzileyo. Ukwenziwa kwezinto ezinkulu kuyahlangabezana neemfuno zophuhliso lwemizi-mveliso.
Kwangowe-1999, iBridgeport yasebenzisa indlela yokwenziwa kwezinto ezizivelisa ngokwazo ukuze ivelise izinto ezizisebenzisayo.Umgubo weSiC, kodwa yasebenzisa i-ethoxysilane kunye ne-phenol resin njengezinto eziluhlaza, nto leyo eyayibiza kakhulu. UGao Pan nabanye basebenzise umgubo we-Si ococekileyo kakhulu kunye nomgubo we-C njengezinto eziluhlaza ukwenza izinto.Umgubo weSiCngempendulo yobushushu obuphezulu emoyeni we-argon. UNing Lina ulungiselele amasuntswana amakhuluUmgubo weSiCngokwenziwa kwesibini.
Isithando sobushushu esiphakathi esiphuhliswa yiSecond Research Institute of China Electronics Technology Group Corporation sixuba ngokulinganayo umgubo we-silicon kunye nomgubo we-carbon kwi-stoichiometric ratio ethile kwaye sizibeke kwi-graphite crucible.isixhobo sokubethela igrafayithiifakwa kwisithando sokufudumala esiphakathi-frequency induction ukuze kufudunyezwe, kwaye utshintsho lobushushu lusetyenziselwa ukudibanisa nokuguqula isigaba sobushushu obuphantsi kunye nesigaba sobushushu obuphezulu ngokulandelelana. Ekubeni ubushushu bempendulo yokwenziwa kwe-β-SiC kwisigaba sobushushu obuphantsi buphantsi kunobushushu be-volatilization be-Si, ukwenziwa kwe-β-SiC phantsi kwe-vacuum ephezulu kunokuqinisekisa ukuba i-self-propagation iyazenzekela. Indlela yokungenisa i-argon, i-hydrogen kunye ne-HCl gas kwi-synthesis ye-α-SiC ithintela ukubola kweUmgubo weSiCkwisigaba sobushushu obuphezulu, kwaye inokunciphisa ngempumelelo umxholo we-nitrogen kwi-α-SiC powder.
I-Shandong Tianyue iyile isithando sokwenziwa, isebenzisa igesi ye-silane njengezinto ze-silicon kunye ne-carbon powder njengezinto ze-carbon. Ubungakanani begesi yezinto eziluhlaza ezifakiweyo bulungiswe ngendlela yokwenza izinto enamanyathelo amabini, kwaye ubungakanani bokugqibela be-silicon carbide particles buphakathi kwe-50 kunye ne-5 000 um.
1 Izinto zokulawula inkqubo yokwenziwa komgubo
1.1 Impembelelo yobukhulu be-powder particles ekukhuleni kwekristale
Ubungakanani besuntswana le-silicon carbide powder bunempembelelo ebaluleke kakhulu ekukhuleni kwekristale enye okulandelayo. Ukukhula kwekristale enye ye-SiC ngendlela ye-PVT kufezekiswa ikakhulu ngokutshintsha umlinganiselo we-molar we-silicon kunye ne-carbon kwicandelo le-gas phase, kwaye umlinganiselo we-molar we-silicon kunye ne-carbon kwicandelo le-gas phase unxulumene nobukhulu besuntswana le-silicon carbide powder. Uxinzelelo olupheleleyo kunye nomlinganiselo we-silicon-carbon wenkqubo yokukhula luyanda ngokuncipha kobukhulu besuntswana. Xa ubungakanani besuntswana buncipha ukusuka kwi-2-3 mm ukuya kwi-0.06 mm, umlinganiselo we-silicon-carbon uyanda ukusuka kwi-1.3 ukuya kwi-4.0. Xa amasuntswana emancinci ukuya kwinqanaba elithile, uxinzelelo oluncinci lwe-Si luyanda, kwaye umaleko wefilimu ye-Si wenziwa phezu komphezulu wekristale ekhulayo, nto leyo ebangela ukukhula kwe-gas-liquid-solid, okuchaphazela i-polymorphism, iziphene zenqaku kunye neziphene zomgca kwikristale. Ke ngoko, ubungakanani besuntswana le-high-purity silicon carbide powder kufuneka bulawulwe kakuhle.
Ukongeza, xa ubukhulu beesuntswana zepowder zeSiC zincinci, umgubo ubola ngokukhawuleza, nto leyo ebangela ukukhula okugqithisileyo kweekristale zeSiC enye. Kwelinye icala, kwindawo enobushushu obuphezulu bokukhula kwekristale enye yeSiC, iinkqubo ezimbini zokwenziwa kunye nokubola zenziwa ngaxeshanye. Umgubo we-silicon carbide uya kubola uze wenze ikhabhoni kwisigaba segesi kunye nesigaba esiqinileyo njengeSi, Si2C, SiC2, nto leyo ebangela ukuba i-polycrystalline powder ibe ne-carbonization enkulu kunye nokwakheka kwe-carbon inclusions kwikristale; kwelinye icala, xa izinga lokubola komgubo likhawuleza, ulwakhiwo lwekristale lwekristale enye yeSiC ekhulileyo lunokutshintsha, nto leyo eyenza kube nzima ukulawula umgangatho wekristale enye yeSiC ekhulileyo.
1.2 Impembelelo yohlobo lwekristale yomgubo ekukhuleni kwekristale
Ukukhula kwekristale enye yeSiC ngendlela yePVT yinkqubo ye-sublimation-recrystallization kubushushu obuphezulu. Uhlobo lwekristale lwezinto eziluhlaza zeSiC lunempembelelo ebalulekileyo ekukhuleni kwekristale. Kwinkqubo yokwenziwa komgubo, isigaba sokwenziwa kobushushu obuphantsi (β-SiC) esinesakhiwo setyhubhu yeseli yeyunithi kunye nesigaba sokwenziwa kobushushu obuphezulu (α-SiC) esinesakhiwo sehexagonal seseli yeyunithi siya kuveliswa ikakhulu. Kukho iintlobo ezininzi zekristale yesilicon carbide kunye noluhlu oluncinci lokulawula ubushushu. Umzekelo, i-3C-SiC iya kuguquka ibe yi-hexagonal silicon carbide polymorph, oko kukuthi i-4H/6H-SiC, kubushushu obungaphezulu kwe-1900°C.
Ngexesha lenkqubo yokukhula kwekristale enye, xa i-β-SiC powder isetyenziselwa ukukhulisa iikristale, umlinganiselo we-silicon-carbon molar ungaphezulu kwe-5.5, ngelixa xa i-α-SiC powder isetyenziselwa ukukhulisa iikristale, umlinganiselo we-silicon-carbon molar yi-1.2. Xa ubushushu bunyuka, kwenzeka utshintsho lwesigaba kwi-crucible. Ngeli xesha, umlinganiselo we-molar kwisigaba segesi uba mkhulu, nto leyo engayi kunceda ukukhula kwekristale. Ukongeza, ezinye izinto ezingcolileyo kwisigaba segesi, kubandakanya i-carbon, i-silicon, kunye ne-silicon dioxide, ziveliswa lula ngexesha lenkqubo yokutshintsha kwesigaba. Ubukho bale nkunkuma bubangela ukuba ikristale ivelise ii-microtubes kunye ne-voids. Ke ngoko, imo yekristale yomgubo kufuneka ilawulwe ngokuchanekileyo.
1.3 Impembelelo yokungcola komgubo ekukhuleni kwekristale
Umxholo wokungcola kwi-SiC powder uchaphazela i-nucleation ezenzekelayo ngexesha lokukhula kwekristale. Okukhona umxholo wokungcola uphezulu, kokukhona amathuba okuba ikristale izenze i-nucleate ngokuzenzekelayo. KwiSiC, ukungcola okuphambili kwesinyithi kuquka i-B, i-Al, i-V, kunye ne-Ni, enokungeniswa zizixhobo zokucubungula ngexesha lokucubungula i-silicon powder kunye ne-carbon powder. Phakathi kwazo, i-B kunye ne-Al zezona zinto ziphambili zokwamkela amandla angaphantsi kwi-SiC, nto leyo ebangela ukwehla kwe-SiC resistivity. Ezinye izinto ezingcolisayo zesinyithi ziya kungenisa amanqanaba amaninzi amandla, nto leyo ebangela iipropati zombane ezingazinzanga zeekristale zeSiC single kubushushu obuphezulu, kwaye zibe nefuthe elikhulu kwiipropati zombane ze-high-purity semi-insulating single crystal substrates, ingakumbi i-resistivity. Ke ngoko, i-high-purity silicon carbide powder kufuneka yenziwe kangangoko kunokwenzeka.
1.4 Impembelelo yomxholo we-nitrogen kumgubo ekukhuleni kwekristale
Inqanaba lomxholo we-nitrogen limisela ukumelana ne-substrate enye yekristale. Abavelisi abakhulu kufuneka balungise uxinaniso lwe-nitrogen doping kwizinto ezenziweyo ngokwenkqubo yokukhula kwekristale evuthiweyo ngexesha lokwenziwa kwepowder. Ii-substrate ze-silicon carbide enye yekristale ecocekileyo kakhulu zezona zinto zithembisayo kwiinxalenye ze-elektroniki ze-military core. Ukuze kukhuliswe ii-substrate ze-crystal enye ecocekileyo kakhulu enokuchasana okuphezulu kunye neempawu zombane ezibalaseleyo, umxholo we-nitrogen engcolileyo ephambili kwi-substrate kufuneka ulawulwe kwinqanaba eliphantsi. Ii-substrate ze-crystal enye eziqhubayo zifuna umxholo we-nitrogen ulawulwe kuxinaniso oluphezulu.
2 Itekhnoloji yokulawula ephambili yokwenza ipowder
Ngenxa yeendawo ezahlukeneyo zokusetyenziswa kwe-silicon carbide substrates, itekhnoloji yokwenziwa kweepowders zokukhula nayo ineenkqubo ezahlukeneyo. Kwipowders zokukhula kwekristale enye eqhubayo yohlobo lwe-N, kufuneka ubumsulwa obuphezulu kunye ne-single phase; ngelixa kwipowders zokukhula kwekristale enye egcina i-semi-insulating, kufuneka ulawulo olungqongqo lomxholo we-nitrogen.
2.1 Ulawulo lobungakanani be-powder particles
2.1.1 Ubushushu bokwenziwa
Ukugcina ezinye iimeko zenkqubo zingatshintshanga, iipowder zeSiC eziveliswa kumaqondo obushushu okwenziwa kwe-1900 ℃, 2000 ℃, 2100 ℃, kunye ne-2200 ℃ zathathwa iisampulu zaza zahlalutywa. Njengoko kubonisiwe kuMfanekiso 1, kunokubonwa ukuba ubungakanani besuntswana buyi-250 ~ 600 μm kwi-1900 ℃, kwaye ubungakanani besuntswana buyanda bufikelela kwi-600 ~ 850 μm kwi-2000 ℃, kwaye ubungakanani besuntswana butshintsha kakhulu. Xa amaqondo obushushu eqhubeka enyuka ukuya kwi-2100 ℃, ubungakanani besuntswana bomgubo weSiC buyi-850 ~ 2360 μm, kwaye ukwanda kudla ngokuba mnene. Ubungakanani besuntswana lweSiC kwi-2200 ℃ buzinzile malunga ne-2360 μm. Ukwanda kobushushu bokwenziwa ukusuka kwi-1900 ℃ kunempembelelo entle kubungakanani besuntswana lweSiC. Xa amaqondo obushushu bokwenziwa eqhubeka enyuka ukusuka kwi-2100 ℃, ubukhulu besuntswana abutshintshi kakhulu. Ngoko ke, xa ubushushu bokwenziwa bubekwe kwi-2100 ℃, ubungakanani obukhulu besuntswana bunokwenziwa ngokusetyenziswa kwamandla okuphantsi.
2.1.2 Ixesha lokwenziwa kwezinto
Ezinye iimeko zenkqubo azitshintshi, kwaye ixesha lokwenziwa limiselwe kwiiyure ezi-4, iiyure ezi-8, kunye neeyure ezili-12 ngokulandelelana. Uhlalutyo lwesampuli yomgubo weSiC oluvelisiweyo luboniswe kuMfanekiso 2. Kufunyaniswe ukuba ixesha lokwenziwa linempembelelo ebalulekileyo kubungakanani besuntswana yeSiC. Xa ixesha lokwenziwa liyiyure ezi-4, ubungakanani besuntswana busasazwa kakhulu kwi-200 μm; xa ixesha lokwenziwa liyiyure ezi-8, ubungakanani besuntswana oluyilwe luyanda kakhulu, ikakhulu lusasazwa malunga ne-1 000 μm; njengoko ixesha lokwenziwa liqhubeka lisanda, ubungakanani besuntswana buyanda ngakumbi, ikakhulu lusasazwa malunga ne-2 000 μm.
2.1.3 Impembelelo yobukhulu bamasuntswana ezinto ezikrwada
Njengoko uthotho lwemveliso yezinto zesilicon zasekhaya luphucuka kancinci kancinci, ubumsulwa bezinto zesilicon buphucuka ngakumbi. Okwangoku, izinto zesilicon ezisetyenziswa ekuhlanganiseni zahlulwe kakhulu zibe yi-granular silicon kunye ne-powdered silicon, njengoko kubonisiwe kuMfanekiso 3.
Izinto ezahlukeneyo ze-silicon eziluhlaza zasetyenziswa ukwenza uvavanyo lokwenziwa kwe-silicon carbide. Uthelekiso lweemveliso zokwenziwa luboniswe kuMfanekiso 4. Uhlalutyo lubonisa ukuba xa kusetyenziswa izinto ze-silicon eziluhlaza eziluhlaza, kukho inani elikhulu lezinto ze-Si kwimveliso. Emva kokuba i-silicon block icoliwe okwesibini, i-Si element kwimveliso yokwenziwa iyancipha kakhulu, kodwa isekhona. Okokugqibela, i-silicon powder isetyenziselwa ukwenziwa, kwaye yi-SiC kuphela ekhoyo kwimveliso. Oku kungenxa yokuba kwinkqubo yokuvelisa, i-silicon enkulu ene-granular kufuneka iqale ifumane i-surface synthesis reaction, kwaye i-silicon carbide yenziwe phezu komphezulu, nto leyo ethintela i-Si powder yangaphakathi ukuba ingadibani ne-C powder. Ke ngoko, ukuba i-block silicon isetyenziswa njengezinto eziluhlaza, kufuneka icolwe ize emva koko ibekwe kwinkqubo yesibini yokwenziwa ukuze kufunyanwe i-silicon carbide powder yokukhula kwekristale.
2.2 Ulawulo lwefomu yekristale yomgubo
2.2.1 Impembelelo yobushushu bokwenziwa
Ukugcina ezinye iimeko zenkqubo zingatshintshanga, ubushushu bokwenziwa buyi-1500℃, 1700℃, 1900℃, kunye ne-2100℃, kwaye umgubo we-SiC ovelisiweyo uyathathwa iisampulu kwaye uhlalutywe. Njengoko kubonisiwe kuMfanekiso 5, i-β-SiC inombala otyheli womhlaba, kwaye i-α-SiC inombala okhanyayo. Ngokujonga umbala kunye nokwakheka komgubo ohlanganisiweyo, kunokuqinisekiswa ukuba imveliso ehlanganisiweyo yi-β-SiC kumaqondo obushushu ayi-1500℃ kunye ne-1700℃. Kwi-1900℃, umbala uba mhlophe, kwaye kuvela amasuntswana ane-hexagonal, okubonisa ukuba emva kokuba ubushushu bunyuke ukuya kwi-1900℃, kwenzeka utshintsho lwesigaba, kwaye inxalenye ye-β-SiC iguqulwa ibe yi-α-SiC; xa ubushushu buqhubeka bunyuka ukuya kwi-2100℃, kufunyaniswa ukuba amasuntswana ahlanganisiweyo acacile, kwaye i-α-SiC ngokusisiseko iguquliwe.
2.2.2 Isiphumo sexesha lokwenziwa kwezinto
Ezinye iimeko zenkqubo azitshintshi, kwaye ixesha lokwenziwa limiselwe kwi-4h, 8h, kunye ne-12h, ngokulandelelana. Umgubo we-SiC ovelisiweyo uyathathwa iisampulu kwaye uhlalutywe yi-diffractometer (XRD). Iziphumo ziboniswe kuMfanekiso 6. Ixesha lokwenziwa linempembelelo ethile kwimveliso eyenziwe yi-SiC powder. Xa ixesha lokwenziwa liyi-4h kunye ne-8 h, imveliso yokwenziwa ikakhulu yi-6H-SiC; xa ixesha lokwenziwa liyi-12 h, kuvela i-15R-SiC kwimveliso.
2.2.3 Impembelelo yomlinganiselo wezinto ezikrwada
Ezinye iinkqubo azitshintshi, ubungakanani bezinto ze-silicon-carbon buyahlalutywa, kwaye ii-ratios ziyi-1.00, 1.05, 1.10 kunye ne-1.15 ngokulandelelanayo kwiimvavanyo zokwenziwa. Iziphumo ziboniswe kuMfanekiso 7.
Kwi-XRD spectrum, kunokubonwa ukuba xa umlinganiselo we-silicon-carbon ungaphezulu kwe-1.05, i-Si engaphezulu iyavela kwimveliso, kwaye xa umlinganiselo we-silicon-carbon ungaphantsi kwe-1.05, kuvela i-C engaphezulu. Xa umlinganiselo we-silicon-carbon uyi-1.05, i-carbon ekhululekileyo kwimveliso yokwenziwa iyasuswa ngokusisiseko, kwaye akukho silicon ekhululekileyo ivelayo. Ke ngoko, umlinganiselo wenani lomlinganiselo we-silicon-carbon kufuneka ube yi-1.05 ukwenza i-SiC ecocekileyo kakhulu.
2.3 Ulawulo lomthamo we-nitrogen ephantsi kumgubo
2.3.1 Izinto ezisetyenzisiweyo
Izinto ezisetyenzisiweyo kolu vavanyo yi-high-purity carbon powder kunye ne-high-purity silicon powder enobubanzi obuphakathi be-20 μm. Ngenxa yobukhulu bayo obuncinci be-particle kunye nommandla omkhulu womphezulu, kulula ukufunxa i-N2 emoyeni. Xa kudityaniswa i-powder, iya kuziswa kwi-crystal form ye-powder. Ukukhula kwee-crystals zohlobo lwe-N, ukungalingani kwe-N2 kwi-powder kukhokelela ekuchaseni okungalinganiyo kwe-crystal kunye notshintsho kwi-crystal form. Umxholo we-nitrogen we-synthesised powder emva kokuba i-hydrogen ingeniswe uphantsi kakhulu. Oku kungenxa yokuba umthamo wee-molecules ze-hydrogen uncinci. Xa i-N2 ifunxwa kwi-carbon powder kunye ne-silicon powder ishushu kwaye ibolile kumphezulu, i-H2 iyasasazeka ngokupheleleyo kwisithuba esiphakathi kwee-powders ngomthamo wayo omncinci, ithathe indawo ye-N2, kwaye i-N2 iphuma kwi-crucible ngexesha lenkqubo yokufunxa, ifezekisa injongo yokususa umxholo we-nitrogen.
2.3.2 Inkqubo yokwenziwa kwezinto
Ngexesha lokwenziwa komgubo we-silicon carbide, ekubeni i-radius yee-athomu ze-carbon kunye nee-athomu ze-nitrogen ifana, i-nitrogen iya kuthatha indawo yezithuba ze-carbon kwi-silicon carbide, ngaloo ndlela inyusa umxholo we-nitrogen. Le nkqubo yovavanyo isebenzisa indlela yokungenisa i-H2, kwaye i-H2 isabela kunye nezinto ze-carbon kunye ne-silicon kwi-synthesis crucible ukuvelisa iigesi ze-C2H2, C2H, kunye ne-SiH. Umxholo wezinto ze-carbon uyanda ngokudluliselwa kwesigaba segesi, ngaloo ndlela kunciphisa izithuba ze-carbon. Injongo yokususa i-nitrogen iyafezekiswa.
2.3.3 Inkqubo yokulawula umxholo we-nitrogen ongasemva
Ii-graphite crucibles ezine-porosity enkulu zingasetyenziswa njengemithombo eyongezelelweyo ye-C ukufunxa umphunga we-Si kwiindawo ze-gas phase, ukunciphisa i-Si kwiindawo ze-gas phase, ngaloo ndlela kwandisa i-C/Si. Kwangaxeshanye, ii-graphite crucibles zinokusabela nomoya we-Si ukuvelisa i-Si2C, i-SiC2 kunye ne-SiC, elingana nomoya we-Si ozisa umthombo we-C kwi-graphite crucible emoyeni wokukhula, ukwandisa umlinganiselo we-C, kunye nokwandisa umlinganiselo we-carbon-silicon. Ke ngoko, umlinganiselo we-carbon-silicon unokwandiswa ngokusebenzisa ii-graphite crucibles ezine-porosity enkulu, ukunciphisa izithuba ze-carbon, kunye nokufezekisa injongo yokususa i-nitrogen.
3 Uhlalutyo kunye noyilo lwenkqubo yokwenziwa komgubo wekristale enye
3.1 Umgaqo kunye noyilo lwenkqubo yokwenziwa kwezinto
Ngolu phando lubanzi lukhankanyiweyo apha ngasentla malunga nolawulo lobungakanani besuntswana, imo yekristale kunye nomxholo we-nitrogen wokwenziwa komgubo, kucetywa inkqubo yokwenziwa. Umgubo we-C ococekileyo ophezulu kunye nomgubo we-Si ziyakhethwa, kwaye zixutywa ngokulinganayo kwaye zilayishwe kwi-graphite crucible ngokwe-silicon-carbon ratio ye-1.05. Amanyathelo enkqubo ahlulwe ngokubanzi ngamanqanaba amane:
1) Inkqubo yokususa i-nitrogen kubushushu obuphantsi, i-vacuum cleaner ukuya kwi-5×10-4 Pa, emva koko ingenisa i-hydrogen, yenza uxinzelelo lwegumbi lube malunga ne-80 kPa, igcinwe imizuzu eli-15, kwaye iphindwe kane. Le nkqubo inokususa izinto ze-nitrogen kumphezulu we-carbon powder kunye ne-silicon powder.
2) Inkqubo yokususa i-nitrogen kubushushu obuphezulu, i-vacuum cleaner ukuya kwi-5×10-4 Pa, emva koko ifudumale ukuya kwi-950 ℃, ize ifake i-hydrogen, iyenze uxinzelelo lwegumbi lube malunga ne-80 kPa, igcinwe imizuzu eli-15, kwaye iphindwe kane. Le nkqubo inokususa izinto ze-nitrogen kumphezulu we-carbon powder kunye ne-silicon powder, kwaye iqhube i-nitrogen kwindawo yobushushu.
3) Ukwenziwa kwenkqubo yesigaba sobushushu obuphantsi, susa i-5×10-4 Pa, uze uyifudumeze ifike kwi-1350℃, uyigcine iiyure ezili-12, uze ufake i-hydrogen ukuze uxinzelelo lwegumbi lube malunga ne-80 kPa, uyigcine iyure e-1. Le nkqubo inokususa i-nitrogen eguquguqukayo ngexesha lenkqubo yokwenziwa.
4) Ukwenziwa kwenkqubo yesigaba sobushushu obuphezulu, kuzaliswe ngomlinganiselo othile wokuhamba komthamo wegesi we-hydrogen ecocekileyo kakhulu kunye ne-argon mixed gas, kwenza uxinzelelo lwegumbi lube malunga ne-80 kPa, kunyuswe ubushushu bube yi-2100℃, kugcinwe iiyure ezili-10. Le nkqubo igqibezela ukuguqulwa komgubo we-silicon carbide ukusuka kwi-β-SiC ukuya kwi-α-SiC kwaye kugqibezele ukukhula kwamasuntswana ekristale.
Okokugqibela, linda ubushushu begumbi buphole bufikelele kubushushu begumbi, uzalise ubushushu obufikelela kuxinzelelo lomoya, uze ukhuphe umgubo.
3.2 Inkqubo yokulungisa umgubo emva kokwenziwa
Emva kokuba umgubo wenziwe ngale nkqubo ingentla, kufuneka ulungiswe emva kokususwa kwekhabhoni ekhululekileyo, isilicon kunye nezinye izinto ezingcolisayo zesinyithi kwaye kuhlolwe ubungakanani besuntswana. Okokuqala, umgubo wenziweyo ufakwa kwi-ball mill ukuze utyunyuzwe, kwaye umgubo we-silicon carbide otyunyuziweyo ufakwa kwi-muffle furnace kwaye ufudunyezwe ukuya kuma-450°C yi-oxygen. I-free carbon ekwi-powder i-oxidized bubushushu ukuze kuveliswe igesi ye-carbon dioxide ephuma kwigumbi, ngaloo ndlela kufezekiswa ukususwa kwe-free carbon. Emva koko, kulungiswa ulwelo lokucoca olune-asidi kwaye lubekwe kumatshini wokucoca isuntswana ye-silicon carbide ukuze kucocwe ukususa i-carbon, isilicon kunye nokungcola kwesinyithi okushiyekileyo okwenziwe ngexesha lenkqubo yokwenza. Emva koko, i-residual acid ihlanjwa ngamanzi acocekileyo kwaye yomiswe. Umgubo owomileyo uvalwa kwiscreen esingcangcazelayo ukuze kukhethwe ubungakanani besuntswana ukuze kukhule ikristale.
Ixesha lokuthumela: Agasti-08-2024