He aha ka CVD SiC Coating?
ʻO ka hoʻoheheʻe ʻana i ka mahu (CVD) kahi kaʻina hana hoʻoheheʻe i hoʻohana ʻia e hana i nā mea paʻa maʻemaʻe kiʻekiʻe. Hoʻohana pinepine ʻia kēia kaʻina hana i ke kahua hana semiconductor e hana i nā kiʻiʻoniʻoni lahilahi ma ka ʻili o nā wafers. Ma ke kaʻina hana o ka hoʻomākaukau ʻana i ka carbide silicon e CVD, ʻike ʻia ka substrate i hoʻokahi a i ʻole nā mea hoʻoheheʻe volatile, e hana kemika ma ka ʻili o ka substrate e waiho i nā waihona carbide silicon i makemake ʻia. Ma waena o nā ʻano hana he nui no ka hoʻomākaukau ʻana i nā mea carbide silicon, ʻo nā huahana i hoʻomākaukau ʻia e ka hoʻoheheʻe ʻana i ka mahu kemika i ʻoi aku ka lōkahi a me ka maʻemaʻe, a ʻo kēia ʻano hana ka mana ikaika o ke kaʻina hana. Loaʻa i nā mea CVD silicon carbide kahi hui kūʻokoʻa o nā mea wela maikaʻi, uila a me nā waiwai kemika, e kūpono loa ia no ka hoʻohana ʻana i ka ʻoihana semiconductor kahi e pono ai nā mea hana kiʻekiʻe. Hoʻohana nui ʻia nā ʻāpana silicon carbide CVD i nā lako etching, nā lako MOCVD, nā lako epitaxial Si a me nā lako epitaxial SiC, nā lako hana hoʻomaʻamaʻa wikiwiki a me nā māla ʻē aʻe.
Ke nānā nei kēia ʻatikala i ka nānā ʻana i ka maikaʻi o nā kiʻiʻoniʻoni lahilahi i ulu ma nā ʻano wela kaʻina hana i ka wā o ka hoʻomākaukau ʻanaʻO ka uhi CVD SiC, no laila e koho i ka wela kaʻina 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 CVD haʻahaʻa haʻahaʻa, a me ka micromorphology o kaʻO ka uhi CVD SiCʻike ʻia e ka nānā ʻana i ka microscopy electron no ka nānā ʻana i kona ʻano nui.
No ka mea he kiʻekiʻe loa ka mahana o ka graphite substrate, e hoʻopau ʻia ke kinoea waena a hoʻokuʻu ʻia mai ka ʻili o ka substrate, a ma hope o ka C a me Si i koe ma ka ʻili substrate e hoʻokumu i ka pae paʻa SiC e hana i ka uhi SiC. Wahi a ke kaʻina hana ulu CVD-SiC ma luna, hiki ke ʻike ʻia e pili ana ka mahana i ka diffusion 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 ke kuleana nui i ka morphology o ka uhi ʻana o SiC. ʻO ka microscopic morphology o ka uhi ʻana ka hōʻike intuitive loa o ka density o ka uhi. No laila, pono e aʻo i ka hopena o nā ʻano wela deposition ma ka microscopic morphology o CVD SiC coating. No ka hiki i ka MTS ke hoʻoheheʻe a waiho i ka uhi SiC ma waena o 900 ~ 1600 ℃, koho kēia hoʻokolohua i ʻelima deposition wela o 900 ℃, 1000 ℃, 1100 ℃, 1200 ℃ a me 1300 ℃ no ka hoʻomākaukau ʻana i ka uhi SiC e aʻo i ka hopena o ka wela ma ka uhi CVD-SiC. Hōʻike ʻia nā ʻāpana kikoʻī ma ka Papa 3. Hōʻike ka Figure 2 i ka microscopic morphology o ka uhi ʻana o CVD-SiC i ulu ma nā ʻano wela deposition.
Ke 900 ℃ ka wela o ka waiho ʻana, ulu ka SiC a pau i nā ʻano fiber. Hiki ke ʻike ʻia he 3.5μm ke anawaena o ka fiber hoʻokahi, a ʻo kona ʻano lākiō ma kahi o 3 (<10). Eia kekahi, ua haku ʻia ia me nā ʻāpana nano-SiC he nui, no laila aia ia i kahi ʻano polycrystalline SiC, ʻokoʻa ia mai nā nanowires SiC kuʻuna a me nā whiskers SiC hoʻokahi-crystalline. ʻO kēia fibrous SiC kahi hemahema i hoʻokumu ʻia e nā ʻāpana kaʻina hana kūpono ʻole. Hiki ke ʻike ʻia ke ʻano o ke ʻano o kēia uhi SiC, a he nui nā pores ma waena o ka fibrous SiC, a haʻahaʻa loa ka density. No laila, ʻaʻole kūpono kēia mahana no ka hoʻomākaukau ʻana i nā uhi SiC paʻa. ʻO ka maʻamau, hoʻokumu ʻia nā hemahema SiC fibrous ma muli o ka haʻahaʻa haʻahaʻa loa. Ma nā haʻahaʻa haʻahaʻa, ʻo nā molekele liʻiliʻi i hoʻopili ʻia ma ka ʻili o ka substrate he haʻahaʻa haʻahaʻa a me ka hiki ʻole ke neʻe. No laila, hiki i nā molekala liʻiliʻi ke neʻe a ulu i ka ikehu haʻahaʻa haʻahaʻa manuahi o nā kīʻaha SiC (e like me ka piko o ka palaoa). ʻO ka hoʻomau ʻana o ka ulu ʻana o ke alakaʻi ʻana e hana i nā hemahema SiC fibrous.
Hoʻomākaukau no ka CVD SiC Coating:
ʻO ka mea mua, hoʻokomo ʻia ka substrate graphite i loko o kahi umu wela wela a mālama ʻia ma 1500 ℃ no 1h ma 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 hoʻonani ʻia ka ʻili o ka poloka graphite me ka sandpaper 1200-mesh e hoʻopau i nā pores ʻili e pili ana i ka waiho ʻana o SiC. Holoi ʻia ka poloka graphite i mālama ʻia me ka ethanol anhydrous a me ka wai distilled, a laila waiho ʻia i loko o ka umu ma 100 ℃ no ka maloʻo. ʻO ka hope, hoʻokomo ʻia ka substrate graphite i loko o ka ʻāpana wela nui o ka umu tubular no ka waiho ʻana o SiC. Hōʻike ʻia ke kiʻikuhi kikoo o ka ʻōnaehana hoʻoheheʻe ʻana i ka mahu kemika ma ke Kiʻi 1.
ʻO kaʻO ka uhi CVD SiCua ʻike ʻia e ka nānā ʻana i ka microscopy electron e nānā i kona nui a me kona ʻano. Eia kekahi, ua helu ʻia ka helu deposition o ka uhi SiC e like me ke ʻano ma lalo nei: VSiC=(m2-m1)/(Sxt)x100% VSiC=Ka helu kuhi; m2–ka nui o ka hāpana uhi (mg); m1-ka nui o ka substrate (mg); S-ʻili o ka ʻāpana (mm2); t-ka manawa waiho (h). He paʻakikī ka CVD-SiC, a hiki ke hōʻuluʻulu ʻia ke kaʻina hana penei: i ka wela kiʻekiʻe, e hoʻoheheʻe ʻia ka MTS e hana i ke kumu kalapona a me ke kumu silikoni liʻiliʻi. ʻO ke kumu kalapona liʻiliʻi ka nui o CH3, C2H2 a me C2H4, a ʻo ke kumu silikona nā molekole liʻiliʻi e komo pū me SiCI2, SiCI3, etc.; E lawe ʻia kēia kumu kalapona a me ke kumu silika liʻiliʻi 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 luna o ka ʻili o ka substrate ma ke ʻano o ka adsorption, a laila e hana ʻia nā hopena kemika ma waena o nā molekele liʻiliʻi e hana i nā kulu liʻiliʻi e ulu mālie, a e lilo nā kulu o ka fuse a me nā kulu. nā huahana waena (HCl gas); Ke piʻi ka mahana i 1000 ℃, hoʻomaikaʻi maikaʻi ʻia ka nui o ka uhi SiC. Hiki ke ʻike ʻia ʻo ka hapa nui o ka uhi ʻana i haku ʻia me nā kīʻaha SiC (ma kahi o 4μm ka nui), akā ʻike ʻia kekahi mau hemahema SiC fibrous, e hōʻike ana aia nō ka ulu ʻana o ka SiC i kēia mahana, a ʻaʻole lawa ka paʻa. Ke piʻi ka mahana i ka 1100 ℃, hiki ke ʻike ʻia ua paʻa loa ka uhi ʻana o ka SiC, a ua nalowale loa nā kīnā SiC fibrous. Hoʻokumu ʻia ka uhi ʻana i nā ʻāpana SiC me ke anawaena o 5 ~ 10μm, i hui pū ʻia. ʻOkaʻiʻo loa ka ʻili o nā ʻāpana. Hoʻokumu ʻia ia me nā huaʻai SiC nano-scale lehulehu. ʻO ka ʻoiaʻiʻo, ʻo ke kaʻina hana ulu CVD-SiC ma 1100 ℃ ua lilo i ka hoʻoili nui ʻana. Loaʻa ka ikehu a me ka manawa o nā molekala liʻiliʻi i hoʻopili ʻia ma ka ʻili o ka substrate e nucleate a ulu i loko o nā kīʻaha SiC. Hoʻohui like ʻia nā huaʻai SiC i nā kulu nui. Ma lalo o ka hana o ka ikehu honua, ʻike ʻia ka hapa nui o nā kulu, a ua hui pū ʻia nā kulu e hana i kahi uhi SiC paʻa. I ka piʻi ʻana o ka mahana i 1200 ℃, ʻoi aku ka paʻakikī o ka uhi ʻana o SiC, akā ʻoi aku ka nui o ka morphology SiC a ʻoi aku ka paʻakikī o ka ʻili o ka uhi. Ke piʻi ka mahana i ka 1300 ℃, loaʻa ka nui o nā ʻāpana spherical maʻamau me ke anawaena o kahi o 3μm ma ka ʻili o ka substrate graphite. ʻO kēia no ka mea ma kēia mahana, ua hoʻololi ʻia ʻo SiC i ka nucleation phase gas, a wikiwiki loa ka helu decomposition MTS. Ua hoʻololi ʻia nā molekala liʻiliʻi a hoʻoheheʻe ʻia e hana i nā hua SiC ma mua o ka hoʻopili ʻia ʻana ma ka ʻili o ka substrate. Ma hope o ka hana ʻana i nā ʻāpana spherical, e hāʻule lākou i lalo, i ka hopena i ka uhi ʻana o ka ʻāpana SiC me ka haʻahaʻa haʻahaʻa. ʻOiaʻiʻo, ʻaʻole hiki ke hoʻohana ʻia ka 1300 ℃ e like me ke ʻano wela o ka uhi ʻana o SiC. Hōʻike ka hoʻohālikelike piha ʻana inā e hoʻomākaukau ʻia ka uhi ʻana o SiC, ʻo ka mahana hoʻoheheʻe CVD maikaʻi loa ʻo 1100 ℃.
Hōʻike ke kiʻi 3 i ka nui o ka waiho ʻana o nā pale CVD SiC ma nā ʻano wela deposition. Ke piʻi aʻe ka mahana deposition, e emi mālie ka helu deposition o ka uhi SiC. ʻO ka nui o ka waihoʻana ma 900 ° C he 0.352 mg · h-1 / mm2, aʻo ka uluʻana o ke kuhikuhiʻana o nā fibers e alakaʻi i ka wikiwiki o ka hoʻopiliʻana. ʻO ka helu deposition o ka uhi ʻana me ka nui kiʻekiʻe he 0.179 mg·h-1/mm2. Ma muli o ka waiho ʻana o kekahi mau ʻāpana SiC, ʻo ka helu deposition ma 1300 ° C ka haʻahaʻa, ʻo 0.027 mg·h-1/mm2 wale nō. Ka hopena: ʻO ka mahana hoʻoheheʻe CVD maikaʻi loa he 1100 ℃. Hoʻoikaika ka haʻahaʻa haʻahaʻa i ka ulu ʻana o ka SiC, aʻo ka wela kiʻekiʻe e hoʻohua ai ʻo SiC i ka hoʻoheheʻe mahu a hopena i ka uhi ʻana. Me ka piʻi ʻana o ka mahana deposition, ka helu deposition oʻO ka uhi CVD SiCemi mālie.
Ka manawa hoʻouna: Mei-26-2025