Menene Rufin CVD SiC?
Tacewar tururin sinadarai (CVD) wani tsari ne na tace tururin da ake amfani da shi wajen samar da kayan da suka yi kauri sosai. Sau da yawa ana amfani da wannan tsari a fannin kera semiconductor don samar da siririn fim a saman wafers. A yayin shirya silicon carbide ta hanyar CVD, substrate yana fuskantar daya ko fiye na abubuwan da suka fara canzawa, wadanda ke yin aiki da sinadarai a saman substrate don ajiye daskararrun silicon carbide da ake so. Daga cikin hanyoyi da yawa na shirya kayan silicon carbide, kayayyakin da aka shirya ta hanyar tace tururin sinadarai suna da daidaito da tsarki mafi girma, kuma wannan hanyar tana da karfin sarrafa tsari. Kayan CVD silicon carbide suna da haɗin kai na musamman na kyawawan halaye na zafi, lantarki da sinadarai, wanda hakan ya sa suka dace sosai don amfani a masana'antar semiconductor inda ake buƙatar kayan aiki masu inganci. Ana amfani da sassan CVD silicon carbide sosai a cikin kayan aikin etching, kayan aikin MOCVD, kayan aikin Si epitaxial da kayan aikin SiC epitaxial, kayan aikin sarrafa zafi mai sauri da sauran fannoni.
Wannan labarin ya mayar da hankali kan nazarin ingancin fina-finan siriri da aka noma a yanayin zafi daban-daban yayin shirye-shiryenRufin CVD SiC, don zaɓar zafin aiki mafi dacewa. Gwajin yana amfani da graphite a matsayin substrate da trichloromethylsilane (MTS) a matsayin iskar gas mai tushen amsawa. Ana ajiye murfin SiC ta hanyar tsarin CVD mai ƙarancin matsin lamba, da kuma micromorphology naRufin CVD SiCAna lura da shi ta hanyar duba na'urar hangen nesa ta lantarki (electronic microscope) don yin nazarin yawan tsarinsa.
Saboda zafin saman substrate na graphite yana da yawa sosai, za a cire iskar gas ta tsakiya a kuma fitar da ita daga saman substrate, kuma a ƙarshe C da Si da suka rage a saman substrate za su samar da SiC mai ƙarfi don samar da murfin SiC. Dangane da tsarin girma na CVD-SiC da ke sama, za a iya ganin cewa zafin jiki zai shafi yaduwar iskar gas, rugujewar MTS, samuwar ɗigo da kuma fitar da iskar gas ta tsakiya, don haka zafin wurin ajiyewa zai taka muhimmiyar rawa a cikin yanayin murfin SiC. Siffar microscopic na murfin shine mafi sauƙin bayyana yawan murfin. Saboda haka, ya zama dole a yi nazarin tasirin yanayin zafi daban-daban na ajiya akan siffar microscopic na murfin CVD SiC. Tunda MTS na iya rugujewa da kuma sanya murfin SiC tsakanin 900 ~ 1600℃, wannan gwajin ya zaɓi zafin ajiya guda biyar na 900℃, 1000℃, 1100℃, 1200℃ da 1300℃ don shirya murfin SiC don nazarin tasirin zafin jiki akan murfin CVD-SiC. An nuna takamaiman sigogi a cikin Tebur 3. Hoto na 2 yana nuna yanayin microscopic na murfin CVD-SiC da aka girma a yanayin zafi daban-daban na ajiya.
Idan zafin wurin ajiya ya kai 900℃, dukkan SiC yana girma zuwa siffofi na zare. Ana iya ganin cewa diamita na zare ɗaya ya kai kusan 3.5μm, kuma rabon fuskarsa ya kai kusan 3 (<10). Bugu da ƙari, ya ƙunshi ƙwayoyin nano-SiC marasa adadi, don haka yana cikin tsarin SiC mai siffar polycrystalline, wanda ya bambanta da nanowires na SiC na gargajiya da kuma gashin SiC mai siffar crystal ɗaya. Wannan siC mai siffar fiber lahani ne na tsarin da ke haifar da sigogin tsari marasa dacewa. Ana iya ganin cewa tsarin wannan siffa ta SiC ba ta da sassauƙa, kuma akwai adadi mai yawa na ramuka tsakanin siC mai siffar fibrous, kuma yawansu yana da ƙasa sosai. Saboda haka, wannan zafin bai dace da shirya sifofin SiC masu yawa ba. Yawanci, lahani na siffa ta SiC mai siffar fibrous yana faruwa ne sakamakon ƙarancin zafin wurin ajiya. A ƙananan yanayin zafi, ƙananan ƙwayoyin da ke shaƙa a saman substrate suna da ƙarancin kuzari da ƙarancin ƙarfin ƙaura. Saboda haka, ƙananan ƙwayoyin suna son ƙaura da girma zuwa mafi ƙarancin kuzarin siffa ta siC (kamar ƙarshen hatsi). Ci gaba da girma a alkibla daga ƙarshe yana haifar da lahani a tsarin siffa ta fibrous SiC.
Shiri na Rufin CVD SiC:
Da farko, ana sanya sinadarin graphite a cikin tanda mai zafi mai zafi sannan a ajiye shi a zafin 1500℃ na tsawon awa 1 a cikin yanayin Ar don cire toka. Sannan a yanka toshewar graphite zuwa toshe mai girman 15x15x5mm, sannan a goge saman toshewar graphite da takarda mai kauri 1200 don kawar da ramukan saman da ke shafar ajiyar SiC. Ana wanke toshewar graphite da aka yi wa magani da ethanol mai hana ruwa da ruwa mai narkewa, sannan a sanya shi a cikin tanda a zafin 100℃ don bushewa. A ƙarshe, an sanya sinadarin graphite a cikin babban yankin zafin tanderu mai bututu don adana SiC. An nuna zane-zanen tsarin adana tururin sinadarai a cikin Hoto na 1.
TheRufin CVD SiCAn lura da shi ta hanyar duba na'urar auna haske ta lantarki don yin nazarin girman barbashi da yawansa. Bugu da ƙari, an ƙididdige ƙimar ajiyar murfin SiC bisa ga dabarar da ke ƙasa: VSiC=(m2-m1)/(Sxt)x100% VSiC=Ƙimar saka hannun jari; m2–nauyin samfurin shafa (mg); m1–nauyin substrate (mg); Yankin saman S na substrate (mm2); t - lokacin ajiyar kuɗi (h). CVD-SiC yana da rikitarwa, kuma ana iya taƙaita tsarin kamar haka: a yanayin zafi mai yawa, MTS za ta fuskanci rugujewar zafi don samar da tushen carbon da ƙananan ƙwayoyin silicon. Ƙananan ƙwayoyin tushen carbon galibi sun haɗa da CH3, C2H2 da C2H4, kuma ƙananan ƙwayoyin tushen silicon galibi sun haɗa da SiCI2, SiCI3, da sauransu; waɗannan ƙananan ƙwayoyin tushen carbon da tushen silicon za a jigilar su zuwa saman substrate na graphite ta hanyar iskar mai ɗaukar kaya da iskar da ke narkewa, sannan waɗannan ƙananan ƙwayoyin za a shake su a saman substrate a cikin nau'in shaƙa, sannan halayen sinadarai za su faru tsakanin ƙananan ƙwayoyin don samar da ƙananan ɗigon ruwa waɗanda ke girma a hankali, kuma ɗigon ruwa suma za su haɗu, kuma amsawar za ta kasance tare da samuwar samfuran tsaka-tsaki (gas ɗin HCl); Idan zafin ya tashi zuwa 1000 ℃, yawan murfin SiC ya inganta sosai. Ana iya ganin cewa yawancin murfin ya ƙunshi ƙwayoyin SiC (kimanin girman 4μm), amma an gano wasu lahani na SiC mai fibrous, wanda ke nuna cewa har yanzu akwai ci gaban SiC a wannan zafin, kuma murfin bai isa ba. Lokacin da zafin ya tashi zuwa 1100 ℃, ana iya ganin cewa murfin SiC yana da yawa sosai, kuma lahani na SiC mai fibrous sun ɓace gaba ɗaya. Rufin ya ƙunshi ƙwayoyin SiC masu siffar ɗigon ruwa tare da diamita na kusan 5 ~ 10 μm, waɗanda aka haɗa su sosai. Fuskar ƙwayoyin tana da ƙarfi sosai. Ya ƙunshi ƙwayoyin SiC marasa adadi marasa adadi. A zahiri, tsarin girma na CVD-SiC a 1100 ℃ ya zama mai sarrafa canja wurin taro. Ƙananan ƙwayoyin da aka lulluɓe a saman substrate suna da isasshen kuzari da lokaci don nucleate da girma zuwa ƙwayoyin SiC. Hatsin SiC suna samar da manyan ɗigon ruwa iri ɗaya. A ƙarƙashin aikin makamashin saman, yawancin ɗigon suna bayyana kamar siffar zagaye, kuma ɗigon suna haɗuwa sosai don samar da rufin SiC mai yawa. Idan zafin ya tashi zuwa 1200℃, murfin SiC ma yana da kauri, amma yanayin SiC ya zama mai kauri da yawa kuma saman murfin ya bayyana da kauri. Lokacin da zafin ya karu zuwa 1300℃, ana samun adadi mai yawa na barbashi masu siffar ƙwallo na yau da kullun tare da diamita na kusan 3μm akan saman substrate na graphite. Wannan saboda a wannan zafin, an canza SiC zuwa nucleation na lokacin iskar gas, kuma ƙimar rushewar MTS tana da sauri sosai. Ƙananan ƙwayoyin halitta sun yi amsawa kuma sun haɗu don samar da hatsin SiC kafin a shake su akan saman substrate. Bayan hatsi sun samar da barbashi masu siffar ƙwallo, za su faɗi ƙasa, daga ƙarshe suna haifar da rufin barbashi na SiC mara kyau tare da ƙarancin yawa. Babu shakka, ba za a iya amfani da 1300℃ azaman zafin jiki na rufin SiC mai kauri ba. Cikakken kwatancen ya nuna cewa idan za a shirya murfin SiC mai kauri, mafi kyawun zafin ajiya na CVD shine 1100℃.
Siffa ta 3 ta nuna ƙimar sakawa na murfin CVD SiC a yanayin zafi daban-daban na sakawa. Yayin da zafin sakawa ke ƙaruwa, ƙimar sakawa na murfin SiC yana raguwa a hankali. Matsakaicin sakawa a 900°C shine 0.352 mg·h-1/mm2, kuma girman alkiblar zaruruwa yana haifar da saurin sakawa. Matsakaicin sakawa na murfin da ya fi yawa shine 0.179 mg·h-1/mm2. Saboda sakawa wasu ƙwayoyin SiC, ƙimar sakawa a 1300°C shine mafi ƙanƙanta, 0.027 mg·h-1/mm2 kawai. Kammalawa: Mafi kyawun zafin ajiyar CVD shine 1100℃. Ƙananan zafin jiki yana haɓaka ci gaban SiC a alkibla, yayin da babban zafin jiki ke sa SiC ya samar da ajiyar tururi kuma yana haifar da ƙarancin rufi. Tare da ƙaruwar zafin ajiyar, ƙimar ajiyarRufin CVD SiCa hankali yana raguwa.
Lokacin Saƙo: Mayu-26-2025