Ka hopena o nā mahana like ʻole ma ka ulu ʻana o ka uhi ʻana o CVD SiC

He aha ka uhi ʻana o CVD SiC?

ʻO ka Chemical vapor deposition (CVD) kahi hana hoʻokaʻawale vacuum i hoʻohana ʻia e hana i nā mea paʻa maʻemaʻe kiʻekiʻe. Hoʻohana pinepine ʻia kēia kaʻina hana ma ke kahua hana semiconductor e hana i nā ʻili lahilahi ma luna o ka ʻili o nā wafers. I ke kaʻina hana o ka hoʻomākaukau ʻana i ka silicon carbide e CVD, ua hōʻike ʻia ka substrate i hoʻokahi a ʻoi aku paha nā mea hoʻomaka volatile, kahi e hana kemika ai ma luna o ka ʻili o ka substrate e waiho i nā waihona silicon carbide i makemake ʻia. Ma waena o nā ʻano hana he nui no ka hoʻomākaukau ʻana i nā mea silicon carbide, ʻoi aku ka like a me ka maʻemaʻe o nā huahana i hoʻomākaukau ʻia e ka chemical vapor deposition, a he ikaika ka mana o kēia ʻano hana. Loaʻa i nā mea CVD silicon carbide kahi hui kūikawā o nā waiwai thermal, uila a me nā kemika maikaʻi loa, e kūpono loa ana no ka hoʻohana ʻana i ka ʻoihana semiconductor kahi e pono ai nā mea hana kiʻekiʻe. Hoʻohana nui ʻia nā ʻāpana CVD silicon carbide i nā lako etching, nā lako MOCVD, nā lako epitaxial Si a me nā lako epitaxial SiC, nā lako hana thermal wikiwiki a me nā ʻoihana ʻē aʻe.

Ke nānā nei kēia ʻatikala i ka nānā ʻana i ka maikaʻi o nā ʻili lahilahi i ulu ʻia ma nā mahana hana like ʻole i ka wā o ka hoʻomākaukau ʻana oʻO ka uhi ʻana o CVD SiC, i mea e koho ai i ka mahana hana kūpono loa. Hoʻohana ka hoʻokolohua i ka graphite ma ke ʻano he substrate a me ka trichloromethylsilane (MTS) ma ke ʻano he kinoea kumu hopena. Hoʻokomo ʻia ka uhi SiC e ke kaʻina hana CVD haʻahaʻa, a me ka micromorphology o kaʻO ka uhi ʻana o CVD SiCʻike ʻia e ka microscopy electron scanning e kālailai i kona nui hoʻonohonoho.

Ma muli o ke kiʻekiʻe loa o ka mahana o ka ʻili o ka substrate graphite, e hoʻohemo ʻia ke kinoea waena a hoʻokuʻu ʻia mai ka ʻili o ka substrate, a ʻo ka hope loa, ʻo C a me Si e koe ana ma ka ʻili o ka substrate e hana i ka pae paʻa SiC e hana i ka uhi SiC. Wahi a ke kaʻina hana ulu CVD-SiC i luna, hiki ke ʻike ʻia e pili ana ka mahana i ka hoʻolaha ʻana o ke kinoea, ka decomposition o MTS, ka hoʻokumu ʻana o nā droplets a me ka desorption a me ka hoʻokuʻu ʻana o ke kinoea waena, no laila e pāʻani ka mahana deposition i kahi kuleana koʻikoʻi i ke ʻano o ka uhi SiC. ʻO ke ʻano microscopic o ka uhi ʻana ka hōʻike intuitive loa o ka density o ka uhi. No laila, pono e aʻo i ka hopena o nā mahana deposition like ʻole ma ke ʻano microscopic o ka uhi CVD SiC. No ka mea hiki i ka MTS ke decompose a waiho i ka uhi SiC ma waena o 900 ~ 1600 ℃, koho kēia hoʻokolohua i ʻelima mau mahana deposition o 900 ℃, 1000 ℃, 1100 ℃, 1200 ℃ a me 1300 ℃ no ka hoʻomākaukau ʻana o ka uhi SiC e aʻo i ka hopena o ka mahana ma ka uhi CVD-SiC. Ua hōʻike ʻia nā palena kikoʻī ma ka Papa 3. Hōʻike ka Kiʻi 2 i ke ʻano microscopic o ka uhi CVD-SiC i ulu ʻia ma nā mahana hoʻokaʻawale like ʻole.

Ke 900 ℃ ka mahana o ka waiho ʻana, ulu nā SiC āpau i nā ʻano fiber. Hiki ke ʻike ʻia he 3.5μm ke anawaena o kahi fiber hoʻokahi, a ʻo kona lakio hiʻohiʻona he 3 (<10). Eia kekahi, ua haku ʻia ia me nā ʻāpana nano-SiC he nui ʻole, no laila no ia i kahi ʻano polycrystalline SiC, kahi ʻokoʻa mai nā nanowires SiC kuʻuna a me nā ʻūmiʻi SiC kristal hoʻokahi. ʻO kēia fibrous SiC kahi kīnā kūkulu i hoʻokumu ʻia e nā palena hana kūpono ʻole. Hiki ke ʻike ʻia he palupalu ke ʻano o kēia uhi SiC, a he nui nā pores ma waena o ka fibrous SiC, a he haʻahaʻa loa ka density. No laila, ʻaʻole kūpono kēia mahana no ka hoʻomākaukau ʻana i nā uhi SiC mānoanoa. ʻO ka maʻamau, ʻo nā hemahema kūkulu fibrous SiC i hoʻokumu ʻia e ka mahana waiho haʻahaʻa loa. I nā mahana haʻahaʻa, ʻo nā mole liʻiliʻi i hoʻopili ʻia ma luna o ka substrate he haʻahaʻa ka ikehu a me ka hiki ke neʻe maikaʻi ʻole. No laila, ʻoi aku ka neʻe ʻana o nā mole liʻiliʻi a ulu i ka ikehu manuahi haʻahaʻa loa o nā hua SiC (e like me ka piko o ka hua). ʻO ka ulu mau ʻana o ke kuhikuhi e hoʻokumu i nā hemahema kūkulu fibrous SiC.

Ka hoʻomākaukau ʻana o ka uhi ʻana o CVD SiC:

ʻO ka mea mua, ua kau ʻia ka substrate graphite i loko o kahi umu hoʻoheheʻe wela kiʻekiʻe a mālama ʻia ma 1500 ℃ no 1 hola i loko o kahi lewa Ar no ka wehe ʻana i ka lehu. A laila ua ʻoki ʻia ka poloka graphite i loko o kahi poloka o 15x15x5mm, a ua hoʻopili ʻia ka ʻili o ka poloka graphite me ka pepa one 1200-mesh e hoʻopau i nā pores o ka ʻili e hoʻopilikia i ka waiho ʻana o SiC. Holoi ʻia ka poloka graphite i mālama ʻia me ka ethanol anhydrous a me ka wai i hoʻoheheʻe ʻia, a laila waiho ʻia i loko o ka umu ma 100 ℃ no ka hoʻomaloʻo ʻana. ʻO ka hope loa, ua kau ʻia ka substrate graphite ma ka ʻāpana mahana nui o ka umu tubular no ka waiho ʻana o SiC. Hōʻike ʻia ke kiʻikuhi schematic o ka ʻōnaehana waiho mahu kemika ma ke Kiʻi 1.

ʻO kaʻO ka uhi ʻana o CVD SiCua nānā ʻia e ka microscopy electron scanning e kālailai i kona nui a me ka nui o nā ʻāpana. Eia kekahi, ua helu ʻia ka helu waiho ʻana o ka uhi SiC e like me ke ʻano ma lalo nei: VSiC=(m2-m1)/(Sxt)x100% VSiC=Ka helu hoʻokaʻawale ʻana; m2–ka nuipa o ka hāpana uhi (mg); m1–ka nuipa o ke substrate (mg); ʻĀpana ʻilikai-S o ke substrate (mm2); t-ka manawa waiho ʻana (h).   He paʻakikī iki ka CVD-SiC, a hiki ke hōʻuluʻulu ʻia ke kaʻina hana penei: i ke kiʻekiʻe o ka mahana, e hana ʻo MTS i ka decomposition thermal e hana i nā molekala kumu kalapona a me nā molekala kumu silicon. ʻO nā molekala kumu kalapona liʻiliʻi e komo pū me CH3, C2H2 a me C2H4, a ʻo nā molekala kumu silicon e komo pū me SiCI2, SiCI3, etc.; a laila e lawe ʻia kēia mau molekala kumu kalapona a me nā molekala kumu silicon i ka ʻili o ka substrate graphite e ke kinoea lawe a me ke kinoea diluent, a laila e hoʻopili ʻia kēia mau molekala liʻiliʻi ma ka ʻili o ka substrate ma ke ʻano o ka adsorption, a laila e hana ʻia nā hopena kemika ma waena o nā molekala liʻiliʻi e hana i nā kulu liʻiliʻi e ulu mālie ana, a e hoʻopili pū nā kulu, a e hele pū ka hopena me ka hoʻokumu ʻia ʻana o nā huahana waena (kinoea HCl); Ke piʻi ka mahana i 1000 ℃, hoʻomaikaʻi nui ʻia ka nui o ka uhi SiC. Hiki ke ʻike ʻia ua haku ʻia ka hapa nui o ka uhi ʻana me nā hua SiC (ma kahi o 4μm ka nui), akā ua loaʻa pū kekahi mau kīnā fibrous SiC, e hōʻike ana aia nō ka ulu ʻana o SiC ma kēia mahana, a ʻaʻole lawa ka paʻa o ka uhi. Ke piʻi ka mahana i 1100 ℃, hiki ke ʻike ʻia he paʻa loa ka uhi SiC, a ua nalowale loa nā kīnā fibrous SiC. Ua haku ʻia ka uhi ʻana me nā ʻāpana SiC ʻano kulu me ke anawaena o kahi o 5 ~ 10μm, i hui pū ʻia. He ʻino loa ka ʻili o nā ʻāpana. Ua haku ʻia me nā hua SiC nano-scale he nui ʻole. ʻO ka ʻoiaʻiʻo, ua lilo ke kaʻina ulu CVD-SiC ma 1100 ℃ i kaohi ʻia o ka hoʻoili nui ʻana. Loaʻa i nā mole liʻiliʻi i hoʻopili ʻia ma ka ʻili o ka substrate ka ikehu a me ka manawa e nucleate a ulu i nā hua SiC. Hoʻokumu like nā hua SiC i nā kulu nui. Ma lalo o ka hana a ka ikehu o ka ʻili, ʻike ʻia ka hapa nui o nā kulu he poepoe, a ua hui pū ʻia nā kulu e hana i kahi uhi SiC mānoanoa. Ke piʻi ka mahana i 1200 ℃, ua paʻapū hoʻi ka uhi SiC, akā ua lilo ke ʻano SiC i multi-ridges a ʻike ʻia ka ʻili o ka uhi ʻana he ʻoi aku ka paʻakikī. Ke piʻi ka mahana i 1300 ℃, ua loaʻa ka nui o nā ʻāpana poepoe maʻamau me ke anawaena o kahi 3μm ma luna o ka ʻili o ka substrate graphite. ʻO kēia no ka mea ma kēia mahana, ua hoʻololi ʻia ʻo SiC i nucleation phase gas, a ua wikiwiki loa ka wikiwiki o ka decomposition MTS. Ua pane a nucleated nā mole liʻiliʻi e hana i nā hua SiC ma mua o ko lākou hoʻopili ʻia ʻana ma ka ʻili o ka substrate. Ma hope o ka hana ʻana o nā hua i nā ʻāpana poepoe, e hāʻule lākou i lalo, a laila e hopena i kahi uhi ʻāpana SiC wehe me ka density haʻahaʻa. ʻIke loa, ʻaʻole hiki ke hoʻohana ʻia ka 1300 ℃ ma ke ʻano he mahana hoʻokumu o ka uhi SiC paʻa. Hōʻike ka hoʻohālikelike piha inā e hoʻomākaukau ʻia ka uhi SiC paʻa, ʻo ka mahana hoʻokaʻawale CVD kūpono loa he 1100 ℃.

Hōʻike ka Kiʻi 3 i ka helu hoʻokomo ʻana o nā uhi CVD SiC ma nā mahana hoʻokomo like ʻole. Ke piʻi aʻe ka mahana hoʻokomo, emi mālie ka helu hoʻokomo o ka uhi SiC. ʻO ka helu hoʻokomo ma 900°C he 0.352 mg·h-1/mm2, a ʻo ka ulu ʻana o nā olonā e alakaʻi i ka helu hoʻokomo wikiwiki loa. ʻO ka helu hoʻokomo o ka uhi me ka nui kiʻekiʻe loa he 0.179 mg·h-1/mm2. Ma muli o ka hoʻokomo ʻana o kekahi mau ʻāpana SiC, ʻo ka helu hoʻokomo ma 1300°C ka haʻahaʻa loa, ʻo 0.027 mg·h-1/mm2 wale nō.   Hopena: ʻO ka mahana hoʻopaʻa CVD maikaʻi loa he 1100 ℃. Hoʻoulu ka mahana haʻahaʻa i ka ulu ʻana o SiC, ʻoiai ke kiʻekiʻe o ka mahana e hoʻoulu ai iā SiC e hana i ka hoʻopaʻa mahu a hopena i ka uhi sparse. Me ka piʻi ʻana o ka mahana hoʻopaʻa, ʻo ka helu hoʻopaʻa oʻO ka uhi ʻana o CVD SiCemi mālie.