Kamar yadda aka nuna a Hoto na 3, akwai hanyoyi guda uku da suka fi tasiri wajen samar da lu'ulu'u guda ɗaya na SiC mai inganci da inganci: epitaxy na lokaci-lokaci na ruwa (LPE), jigilar tururin jiki (PVT), da kuma adana tururin sinadarai masu zafi (HTCVD). PVT tsari ne mai kyau na samar da lu'ulu'u guda ɗaya na SiC, wanda ake amfani da shi sosai a manyan masana'antun wafer.
Duk da haka, dukkan hanyoyin guda uku suna ci gaba da bunƙasa cikin sauri da kuma sabbin abubuwa. Har yanzu ba zai yiwu a tantance wane tsari za a yi amfani da shi sosai a nan gaba ba. Musamman ma, an bayar da rahoton cewa lu'ulu'u guda ɗaya na SiC mai inganci wanda aka samar ta hanyar haɓakar mafita a cikin adadi mai yawa a cikin 'yan shekarun nan, girman SiC a cikin matakin ruwa yana buƙatar ƙaramin zafin jiki fiye da na sublimation ko tsarin ajiya, kuma yana nuna ƙwarewa wajen samar da substrates na SiC na nau'in P (Tebur 3) [33, 34].
Hoto na 3: Tsarin dabarun girma guda uku na SiC guda ɗaya masu rinjaye: (a) epitaxy na lokaci-lokaci na ruwa; (b) jigilar tururi ta zahiri; (c) ajiyar tururin sinadarai mai zafi mai yawa
Tebur na 3: Kwatanta LPE, PVT da HTCVD don haɓaka lu'ulu'u guda ɗaya na SiC [33, 34]
Ci gaban mafita fasaha ce ta yau da kullun don shirya semiconductors masu haɗaka [36]. Tun daga shekarun 1960, masu bincike sun yi ƙoƙarin ƙirƙirar lu'ulu'u a cikin mafita [37]. Da zarar an haɓaka fasahar, za a iya sarrafa cikakken cikar saman girma sosai, wanda ke sa hanyar mafita ta zama fasaha mai kyau don samun ingots na lu'ulu'u guda ɗaya masu inganci.
Don haɓakar mafita na lu'ulu'u guda ɗaya na SiC, tushen Si ya samo asali ne daga narkewar Si mai tsarki sosai yayin da graphite crucible ke aiki da dalilai biyu: na'urar dumama da tushen C solute. Lu'ulu'u guda ɗaya na SiC sun fi girma a ƙarƙashin rabon stoichiometric mafi kyau lokacin da rabon C da Si ya kusa da 1, yana nuna ƙarancin lahani [28]. Duk da haka, a matsin lamba na yanayi, SiC ba ya nuna wurin narkewa kuma yana ruɓewa kai tsaye ta hanyar tururi a yanayin zafi sama da 2,000 °C. Narkewar SiC, bisa ga tsammanin ka'ida, ana iya samunsa ne kawai a ƙarƙashin tsanani daga zane-zanen Si-C binary (Hoto na 4) wanda a yanayin zafi da tsarin mafita suka nuna. Mafi girman narkewar C a cikin Si ya bambanta daga 1at.% zuwa 13at.%. Babban ƙarfin C na ci gaba, mafi sauri saurin girma, yayin da ƙarancin ƙarfin C na ci gaban shine C supersaturation wanda matsin lamba ya mamaye na 109 Pa da yanayin zafi sama da 3,200 °C. Yana iya samar da saman da ya yi santsi [22, 36-38].Yanayin zafi tsakanin 1,400 da 2,800 °C, narkewar C a cikin narkewar Si ya bambanta daga 1at.% zuwa 13at.%. Ƙarfin da ke haifar da girma shine saman C wanda ke ƙarƙashin tsarin yanayin zafi da mafita. Mafi girman saman C, mafi sauri saurin girma, yayin da ƙaramin saman C ke samar da saman da ya yi santsi [22, 36-38].
Hoto na 4: Zane-zanen mataki na biyu na Si-C [40]
Abubuwan ƙarfe masu canzawa ko abubuwan ƙasa masu wuya ba wai kawai suna rage zafin girma yadda ya kamata ba, har ma da alama ita ce hanya ɗaya tilo da za a inganta narkewar carbon a cikin narkewar Si. Ƙara ƙarfe masu canzawa, kamar Ti [8, 14-16, 19, 40-52], Cr [29, 30, 43, 50, 53-75], Co [63, 76], Fe [77-80], da sauransu ko ƙarfe masu wuya, kamar Ce [81], Y [82], Sc, da sauransu zuwa narkewar Si yana ba da damar narkewar carbon ya wuce 50% a cikin yanayin da ke kusa da ma'aunin thermodynamic. Bugu da ƙari, dabarar LPE ta dace da allurar P-type na SiC, wanda za'a iya cimmawa ta hanyar haɗa Al cikin
sinadarin narkewa [50, 53, 56, 59, 64, 71-73, 82, 83]. Duk da haka, haɗa Al yana haifar da ƙaruwa a cikin juriyar lu'ulu'u guda ɗaya na nau'in P-type SiC [49, 56]. Baya ga haɓakar nau'in N a ƙarƙashin shan nitrogen,
Girman mafita gabaɗaya yana faruwa ne a cikin yanayin iskar gas mara aiki. Duk da cewa helium (He) ya fi argon tsada, masana da yawa sun fi son shi saboda ƙarancin ɗankonsa da kuma yawan watsa zafi (sau 8 na argon) [85]. Yawan ƙaura da abun ciki na Cr a cikin 4H-SiC suna kama da juna a ƙarƙashin yanayin He da Ar, an tabbatar da cewa girma a ƙarƙashin Heresults a cikin mafi girman ƙimar girma fiye da girma a ƙarƙashinAr saboda yawan watsa zafi na mai riƙe da iri [68]. Yana hana samuwar voids a cikin lu'ulu'u da aka girma da kuma nucleation na bazata a cikin maganin, to, ana iya samun yanayin saman da ya yi santsi [86].
Wannan takarda ta gabatar da haɓakawa, aikace-aikace, da halayen na'urorin SiC, da kuma manyan hanyoyi guda uku don haɓaka lu'ulu'u guda ɗaya na SiC. A cikin sassan da ke gaba, an sake duba dabarun haɓaka mafita na yanzu da mahimman sigogi masu dacewa. A ƙarshe, an gabatar da hangen nesa wanda ya tattauna ƙalubalen da ayyukan da za a yi nan gaba game da yawan girma na lu'ulu'u guda ɗaya na SiC ta hanyar hanyar mafita.
Lokacin Saƙo: Yuli-01-2024