Monga momwe zasonyezedwera pa Chithunzi 3, pali njira zitatu zazikulu zomwe cholinga chake ndi kupatsa SiC single crystal yapamwamba komanso yogwira ntchito bwino: liquid phase epitaxy (LPE), physical vapor transport (PVT), ndi high-temperature chemical vapor deposition (HTCVD). PVT ndi njira yodziwika bwino yopangira SiC single crystal, yomwe imagwiritsidwa ntchito kwambiri ndi opanga ma wafer akuluakulu.
Komabe, njira zonse zitatuzi zikusintha mofulumira komanso zatsopano. Sizingatheke kudziwa njira yomwe idzagwiritsidwe ntchito kwambiri mtsogolomu. Makamaka, kristalo imodzi ya SiC yapamwamba kwambiri yopangidwa ndi kukula kwa yankho pamlingo waukulu yanenedwa m'zaka zaposachedwa, kukula kwa SiC mu gawo lamadzimadzi kumafuna kutentha kotsika kuposa kwa sublimation kapena deposition process, ndipo ikuwonetsa luso popanga P-type SiC substrates (Table 3) [33, 34].
Chithunzi 3: Ndondomeko ya njira zitatu zazikulu zokulira za SiC single crystal: (a) liquid phase epitaxy; (b) physical nthunzi transport; (c) high temperature chemical vapor deposition
Gome 3: Kuyerekeza kwa LPE, PVT ndi HTCVD pakukula makristalo amodzi a SiC [33, 34]
Kukula kwa yankho ndi ukadaulo wokhazikika wokonzekera ma semiconductors a compound [36]. Kuyambira m'ma 1960, ofufuza ayesa kupanga kristalo mu yankho [37]. Ukapanga ukadaulo, supersaturation ya pamwamba pa kukula imatha kulamulidwa bwino, zomwe zimapangitsa njira yothetsera vutoli kukhala ukadaulo wodalirika wopezera ma ingot apamwamba a kristalo imodzi.
Pakukula kwa yankho la kristalo imodzi ya SiC, gwero la Si limachokera ku kusungunuka kwa Si koyera kwambiri pomwe graphite crucible imagwira ntchito ziwiri: chotenthetsera ndi gwero la C solute. Makristalo amodzi a SiC amatha kukula pansi pa chiŵerengero choyenera cha stoichiometric pamene chiŵerengero cha C ndi Si chili pafupi ndi 1, kusonyeza kuchepa kwa defect defect [28]. Komabe, pa pressure ya mumlengalenga, SiC simasonyeza malo osungunuka ndipo imawola mwachindunji kudzera mu nthunzi pa kutentha kopitilira 2,000 °C. Kusungunuka kwa SiC, malinga ndi ziyembekezo za chiphunzitso, kumatha kupangidwa kokha pansi pa severe kuwoneka kuchokera ku chithunzi cha Si-C binary phase (Chithunzi 4) chomwe chili pa kutentha kwa gradient ndi solution system. C ikakwera mu Si melt imasiyana kuyambira 1at.% mpaka 13at.%. Kuchuluka kwa C komwe kumayendetsa, kumabweretsa kukula kwachangu, pomwe mphamvu yotsika ya C ya kukula ndi C supersaturation yomwe imayendetsedwa ndi 109 Pa ndi kutentha kopitilira 3,200 °C. Kuchuluka kwa madzi kungapangitse kuti pamwamba pakhale posalala [22, 36-38]. Kutentha kwake kuli pakati pa 1,400 ndi 2,800 °C, kusungunuka kwa C mu Si melt kumasiyana kuyambira 1at.% mpaka 13at.%. Mphamvu yoyendetsera kukula ndi C supersaturation yomwe imayendetsedwa ndi kutentha ndi njira yothetsera. C supersaturation ikakwera, kuchuluka kwa madzi kumawonjezeka mofulumira, pomwe C supersaturation yotsika imapanga pamwamba posalala [22, 36-38].
Chithunzi 4: Chithunzi cha Si-C binary phase [40]
Kugwiritsira ntchito mankhwala osokoneza bongo kapena zinthu zosadziwika bwino za dziko lapansi sikuti kumangochepetsa kutentha kwa kukula kokha komanso kumawoneka ngati njira yokhayo yowonjezera kusungunuka kwa kaboni mu Si melt. Kuwonjezera kwa zitsulo zosinthika, monga Ti [8, 14-16, 19, 40-52], Cr [29, 30, 43, 50, 53-75], Co [63, 76], Fe [77-80], ndi zina zotero kapena zitsulo zosadziwika bwino za dziko lapansi, monga Ce [81], Y [82], Sc, ndi zina zotero. ku Si melt kumalola kusungunuka kwa kaboni kupitirira 50at.% mu mkhalidwe woyandikira thermodynamic equilibrium. Kuphatikiza apo, njira ya LPE ndi yabwino pa P-type doping ya SiC, yomwe ingapezeke mwa kuphatikiza Al mu
Zosungunulira [50, 53, 56, 59, 64, 71-73, 82, 83]. Komabe, kulowetsedwa kwa Al kumabweretsa kuwonjezeka kwa resistivity ya makristalo amodzi a P-type SiC [49, 56]. Kupatula kukula kwa mtundu wa N pansi pa nitrogen doping,
Kukula kwa yankho nthawi zambiri kumachitika mumlengalenga wopanda mpweya. Ngakhale kuti helium (He) ndi yokwera mtengo kuposa argon, akatswiri ambiri amaikonda chifukwa cha kukhuthala kwake kochepa komanso kutentha kwambiri (nthawi 8 za argon) [85]. Kuchuluka kwa kusamuka ndi kuchuluka kwa Cr mu 4H-SiC ndizofanana pansi pa mlengalenga wa He ndi Ar, zatsimikiziridwa kuti kukula pansi pa Heresults mu kukula kwakukulu kuposa kukula pansi paAr chifukwa cha kutentha kwakukulu kwa chogwirira mbewu [68]. Imalepheretsa kupangika kwa voids mkati mwa kristalo wokulirapo ndi nucleation yodzidzimutsa mu yankho, ndiye kuti, mawonekedwe osalala a pamwamba angapezeke [86].
Pepala ili linafotokoza za chitukuko, ntchito, ndi makhalidwe a zipangizo za SiC, ndi njira zitatu zazikulu zokulira kristalo imodzi ya SiC. M'magawo otsatirawa, njira zamakono zokulira yankho ndi magawo ofunikira ofanana adawunikidwanso. Pomaliza, malingaliro adaperekedwa omwe adakambirana za zovuta ndi ntchito zamtsogolo zokhudzana ndi kukula kwakukulu kwa makristalo amodzi a SiC kudzera mu njira yothetsera vutoli.
Nthawi yotumizira: Julayi-01-2024