Nūhou - Ka ʻenehana a me ka ulu ʻana o ka silikon carbide (Ⅱ)

ʻO ka hā, ke ʻano hoʻoili mahu kino

ʻO kaka halihali mahu kino (PVT)ʻO ke ala i hoʻokumu ʻia mai ka ʻenehana sublimation phase vapor i haku ʻia e Lely i ka makahiki 1955. Hoʻokomo ʻia ka pauka SiC i loko o kahi paipu graphite a hoʻomehana ʻia i ka wela kiʻekiʻe e decompose a sublimate i ka pauka SiC, a laila hoʻomaha ʻia ka paipu graphite. Ma hope o ka hoʻoheheʻe ʻia ʻana o ka pauka SiC, waiho ʻia nā ʻāpana mokuahi a hoʻoheheʻe ʻia i loko o nā kristal SiC a puni ka paipu graphite. ʻOiai ua paʻakikī kēia ʻano i ka loaʻa ʻana o nā kristal hoʻokahi SiC nui, a paʻakikī ke kaʻina hana deposition i ka paipu graphite, hāʻawi ia i nā manaʻo no nā mea noiʻi ma hope.
Ym Terairov et al. ma Rūsia ua hoʻokomo i ka manaʻo o nā kristal hua ma kēia kumu a hoʻonā i ka pilikia o ke ʻano aniani ʻole a me ke kūlana nucleation o nā kristal SiC. Ua hoʻomau ka poʻe noiʻi ma hope i ka hoʻomaikaʻi ʻana a hoʻomohala i ke ʻano o ka lawe ʻana i ke kinoea kino (PVT) i ka hoʻohana ʻana i nā ʻoihana i kēia lā.

ʻO ke ʻano o ka ulu ʻana o ka kristal SiC mua loa, ʻo ke ʻano o ka hoʻololi ʻana i ka mahu kino ke ʻano ulu nui loa no ka ulu ʻana o ka kristal SiC. Ke hoʻohālikelikeʻia me nāʻano hana'ē aʻe, he haʻahaʻa ko keʻano no nā mea ulu ulu, kahi kaʻina hana ulu maʻalahi, ka mana ikaika, ka hoʻomohala pono, a me ka noiʻi, a uaʻike i ka noiʻoihana. Hōʻike ʻia ke ʻano o ke aniani i ulu ʻia e ke ʻano PVT mainstream i kēia kiʻi.

Hiki ke hoʻomalu ʻia nā māla wela axial a me ka radial ma ke kāohi ʻana i nā kūlana insulation thermal waho o ka graphite crucible. Hoʻonoho ʻia ka pauka SiC ma lalo o ka pahu graphite me kahi mahana kiʻekiʻe, a ua hoʻopaʻa ʻia ke aniani hua SiC ma luna o ka pahu graphite ma kahi haʻahaʻa haʻahaʻa. ʻO ka mamao ma waena o ka pauda a me ka ʻanoʻano ke hoʻomalu ʻia he ʻumi millimeters e pale aku i ka pilina ma waena o ke aniani hoʻokahi e ulu ana a me ka pauda. ʻO ka gradient mahana ma ka laulā o 15-35 ℃/cm. Mālama ʻia kahi kinoea inert o 50-5000 Pa i loko o ka umu e hoʻonui ai i ka convection. Ma kēia ala, ma hope o ka hoʻomehana ʻia ʻana o ka pauka SiC i 2000-2500 ℃ e ka hoʻomehana induction, e hoʻoheheʻe ʻia ka pauka SiC a hoʻoheheʻe ʻia i loko o Si, Si2C, SiC2 a me nā mea mahu, a lawe ʻia i ka hopena o ka hua me ka convection kinoea, a Hoʻopili ʻia ke aniani SiC ma luna o ke aniani hua no ka hoʻokō ʻana i ka ulu aniani hoʻokahi. ʻO kona ulu ulu maʻamau he 0.1-2mm / h.

ʻO ke kaʻina hana PVT e kālele ana i ka mālama ʻana i ka wela o ka ulu ʻana, ka gradient mahana, ka ulu ʻana o ka ʻili, ka spacing ʻili o nā mea waiwai, a me ke kaomi ulu ʻana, ʻo kona pōmaikaʻi ʻo ia ke ʻano o ke kaʻina hana, maʻalahi nā mea maka, haʻahaʻa ke kumukūʻai, akā ke kaʻina ulu. ʻO ke ʻano o ka PVT he paʻakikī ke nānā aku, ka nui o ka ulu ʻana o ka kristal o 0.2-0.4mm / h, paʻakikī ke ulu i nā kristal me ka mānoanoa nui (> 50mm). Ma hope o nā makahiki he ʻumi o ka hoʻomau mau ʻana, ua nui loa ka mākeke o kēia manawa no nā wafers substrate SiC i ulu ʻia e ke ʻano PVT, a hiki i ka puka makahiki o nā wafers substrate SiC hiki ke hiki i nā haneli he mau tausani o nā wafers, a ke loli mālie nei kona nui mai 4 iniha a 6 'īniha, a ua hoʻomohala i 8 ʻīniha o nā laʻana substrate SiC.

ʻElima, ʻO ke ʻano hoʻoheheʻe ʻana i ka mahu kemika kiʻekiʻe

ʻO ka High-Temperature Chemical Vapor Deposition (HTCVD) kahi hana i hoʻomaikaʻi ʻia e pili ana i ka Chemical Vapor Deposition (CVD). Ua noi mua ʻia ke ʻano hana ma 1995 e Kordina et al., Linkoping University, Sweden.
Hōʻike ʻia ke kiʻikuhi ulu ulu ma ke kiʻi:

Ke ulu ʻia ke aniani SiC e ke kaʻina hana wai, hōʻike ʻia ka mahana a me ka hoʻohele convection i loko o ka hopena kōkua ma ke kiʻi:

Hiki ke ʻike ʻia ʻoi aku ka kiʻekiʻe o ka mahana ma kahi kokoke i ka paia crucible i loko o ka hoʻonā kōkua, ʻoiai ʻoi aku ka haʻahaʻa o ka mahana ma ke aniani hua. I ka wā o ka ulu ʻana, hāʻawi ka graphite crucible i kahi kumu C no ka ulu aniani. Ma muli o ke kiʻekiʻe o ka mahana ma ka paia crucible, nui ka solubility o C, a me ka wikiwiki o ka hoʻoheheʻe ʻana, e hoʻoheheʻe ʻia ka nui o C ma ka paia crucible e hana i kahi hopena saturated o C. ʻO kēia mau hāʻina me ka nui nui. ʻO ka C i hoʻoheheʻe ʻia e lawe ʻia i ka ʻaoʻao haʻahaʻa o nā kristal hua ma o ka convection i loko o ka hopena kōkua. Ma muli o ka haʻahaʻa haʻahaʻa o ka hopena aniani o ka hua, ua emi like ka solubility o ka C e pili ana, a ua lilo ka hopena C-saturated i kahi hopena supersaturated o C ma hope o ka hoʻololi ʻana i ka hopena haʻahaʻa ma lalo o kēia kūlana. Hiki i ka Supersaturated C i ka hoʻonā i hui pū ʻia me Si i loko o ka hoʻonā kōkua hiki ke ulu i ka epitaxial kristal SiC ma luna o ke aniani hua. Ke hoʻoheheʻe ʻia ka ʻāpana ʻāwī o C, e hoʻi ka hopena i ka hopena wela kiʻekiʻe o ka paia crucible me ka convection a hoʻoheheʻe hou iā C no ka hana ʻana i ka hopena saturated.

Hoʻopau hou ke kaʻina hana, a ulu ka SiC crystal. I ke kaʻina o ka ulu ʻana o ka wai, ʻo ka hoʻoheheʻe ʻana a me ka ua o C i ka hoʻonā he mea koʻikoʻi nui o ka holomua ulu. I mea e hōʻoia ai i ka ulu ʻana o ka kristal paʻa, pono e mālama i kahi kaulike ma waena o ka hoʻoheheʻe ʻana o C ma ka paia crucible a me ka ua ma ka hopena o ka hua. Inā ʻoi aku ka nui o ka hoʻoheheʻe ʻana o C ma mua o ka ua o C, a laila e hoʻonui mālie ʻia ka C i loko o ke aniani, a e kū mai ka nucleation o SiC. Inā ʻoi aku ka liʻiliʻi o ka hoʻoheheʻe ʻana o C ma mua o ka ua o C, e paʻakikī ka ulu ʻana o ke aniani ma muli o ka nele o ka solute.
I ka manawa like, ʻo ka lawe ʻana o C ma ka convection e pili pū i ka hāʻawi ʻana o C i ka wā ulu. I mea e ulu ai i nā kristal SiC me ka maikaʻi o ka kristal maikaʻi a me ka mānoanoa lawa, pono e hōʻoia i ke koena o nā mea ʻekolu i luna, e hoʻonui nui ai i ka paʻakikī o ka ulu ʻana o ka wai wai SiC. Eia nō naʻe, me ka hoʻomaikaʻi lohi ʻana a me ka hoʻomaikaʻi ʻana i nā ʻenehana pili a me nā ʻenehana, e hōʻike lohi ʻia nā pōmaikaʻi o ka ulu ʻana o ka wai o nā kristal SiC.
I kēia manawa, hiki ke hoʻokō ʻia ka ulu ʻana o ka wai o 2-inch SiC crystals ma Iapana, a ke kūkulu ʻia nei ka ulu ʻana o ka wai o nā kristal 4-inch. I kēia manawa, ʻaʻole i ʻike ka noiʻi kūloko pili i nā hopena maikaʻi, a pono e hahai i ka hana noiʻi kūpono.

ʻEhiku, Nā waiwai kino a me nā kemika o nā kristal SiC

(1) Nā waiwai mīkini: He kiʻekiʻe kiʻekiʻe ka paʻakikī o nā kristal SiC a me ke kūpaʻa maikaʻi. Aia kona paʻakikī Mohs ma waena o 9.2 a me 9.3, a ʻo kona paʻakikī Krit ma waena o 2900 a me 3100Kg/mm2, ʻo ia ka lua o nā kristal daimana ma waena o nā mea i ʻike ʻia. Ma muli o nā waiwai mechanical maikaʻi loa o SiC, hoʻohana pinepine ʻia ka pauka SiC i ka ʻoihana ʻokiʻoki a wili paha, me ka koi makahiki a hiki i nā miliona o nā tona. E hoʻohana pū ka uhi pale ʻaʻahu ma kekahi mau mea hana i ka uhi SiC, no ka laʻana, ʻo ka uhi pale ʻaʻahu ma kekahi mau moku kaua i haku ʻia me ka uhi SiC.

(2) Nā waiwai wela: Hiki i ka conductivity thermal o SiC ke hiki i 3-5 W / cm·K, ʻo ia ka 3 mau manawa o ka semiconductor kahiko Si a me 8 mau manawa o GaAs. Hiki ke hoʻokuʻu koke ʻia ka hana wela o ka mea i hoʻomākaukau ʻia e SiC, no laila ua ʻoluʻolu nā koi o nā kūlana hoʻoheheʻe wela o ka hāmeʻa SiC, a ʻoi aku ka maikaʻi no ka hoʻomākaukau ʻana i nā mea mana kiʻekiʻe. Loaʻa iā SiC nā waiwai thermodynamic paʻa. Ma lalo o nā kūlana kaomi maʻamau, e hoʻoheheʻe ʻia ʻo SiC i loko o kahi mahu i loaʻa iā Si a me C ma ke kiʻekiʻe.

(3) Nā waiwai kemika: Loaʻa i ka SiC nā waiwai kemika paʻa, kūpaʻa maikaʻi i ka corrosion, a ʻaʻole e pane me kekahi waika i ʻike ʻia ma ke ana wela. Hoʻokomo ʻia ʻo SiC i ka lewa no ka manawa lōʻihi e hana mālie i kahi ʻāpana lahilahi o ka SiO2 paʻa, e pale ana i nā hopena oxidation hou aʻe. Ke piʻi ka mahana i ʻoi aku ma mua o 1700 ℃, hoʻoheheʻe ka ʻāpana lahilahi SiO2 a oxidize wikiwiki. Hiki i ka SiC ke hana i ka hopena oxidation lohi me nā mea hoʻoheheʻe ʻia a i ʻole nā kumu, a ua ʻino ʻia nā wafers SiC i loko o KOH a me Na2O2 i hoʻoheheʻe ʻia e ʻike i ka wehe ʻana i nā kristal SiC.

(4) Nā waiwai uila: ʻO SiC ma ke ʻano he mea hōʻike no nā semiconductor bandgap ākea, 6H-SiC, a me 4H-SiC bandgap ākea he 3.0 eV a me 3.2 eV pākahi, ʻo ia ka 3 manawa o ka Si a me 2 manawa o GaAs. ʻO nā ʻenehana Semiconductor i hana ʻia me SiC he liʻiliʻi liʻiliʻi o ka leakage a me ka nui o nā māla uila, no laila ua manaʻo ʻia ʻo SiC he mea kūpono no nā mea mana kiʻekiʻe. ʻO ka mobility electron saturated o SiC he 2 mau manawa kiʻekiʻe ma mua o ka Si, a loaʻa iā ia nā pōmaikaʻi maopopo i ka hoʻomākaukau ʻana i nā hāmeʻa kiʻekiʻe. Hiki ke loaʻa nā kristal SiC P-type a i ʻole N-type SiC crystals ma ka doping ʻana i nā ʻātoma haumia i loko o nā kristal. I kēia manawa, hoʻohana nui ʻia nā kristal SiC P-type e Al, B, Be, O, Ga, Sc, a me nā mea ʻē aʻe, a ʻo N-type sic crystals e doped nui ʻia e nā N atoms. ʻO ka ʻokoʻa o ka hoʻopaʻa ʻana o ka doping a me ke ʻano e loaʻa i ka hopena nui i nā waiwai kino a me nā kemika o SiC. I ka manawa like, hiki ke hoʻopaʻa ʻia ka mea lawe manuahi e ka doping hohonu e like me V, hiki ke hoʻonui ʻia ka resistivity, a hiki ke loaʻa ka semi-insulating SiC crystal.

(5) Nā waiwai Optical: Ma muli o ke ākea ākea ākea, ʻaʻohe kala a me ka ʻike ʻole ke aniani SiC undoped. Hōʻike nā kristal SiC doped i nā kala like ʻole ma muli o ko lākou mau waiwai like ʻole, no ka laʻana, ʻōmaʻomaʻo ʻo 6H-SiC ma hope o ka doping N; 4H-SiC ʻeleʻele. He melemele ka 15R-SiC. Hoʻopili ʻia me Al, ʻike ʻia ʻo 4H-SiC i polū. He ala intuitive ia e hoʻokaʻawale i ke ʻano kristal SiC ma ka nānā ʻana i ka ʻokoʻa o ke kala. Me ka noiʻi mau ʻana i nā kahua pili i ka SiC i nā makahiki 20 i hala iho nei, ua hana ʻia nā holomua nui i nā ʻenehana pili.

ʻEwalu, Hoʻokomo i ke kūlana hoʻomohala SiC

I kēia manawa, ʻoi aku ka maikaʻi o ka ʻoihana SiC, mai nā wafers substrate,aepitaxialwafersi ka hana ʻana i nā mea hana, a me ka hoʻopili ʻana, ua oʻo ke kaulahao ʻoihana holoʻokoʻa, a hiki iā ia ke hāʻawi i nā huahana pili i ka SiC i ka mākeke.

He alakaʻi ʻo Cree i ka ʻoihana ulu kristal SiC me kahi kūlana alakaʻi i ka nui a me ka maikaʻi o nā wafers substrate SiC. Ke hana nei ʻo Cree i kēia manawa he 300,000 SiC substrate chips i kēlā me kēia makahiki, ʻoi aku ma mua o 80% o nā hoʻouna honua.

I Kepakemapa 2019, hoʻolaha ʻo Cree e kūkulu ʻo ia i kahi hale hou ma New York State, USA, e hoʻohana i ka ʻenehana kiʻekiʻe loa e hoʻonui i ka mana 200 mm anawaena a me RF SiC substrate wafers, e hōʻike ana i kāna ʻenehana hoʻomākaukau mea substrate 200 mm SiC. lilo i kanaka makua.

I kēia manawa, ʻo nā huahana koʻikoʻi o SiC substrate chips ma ka mākeke ʻo 4H-SiC a me 6H-SiC conductive a me nā ʻano semi-insulated o 2-6 iniha.
I ʻOkakopa 2015, ʻo Cree ka mea mua i hoʻomaka i ka 200 mm SiC substrate wafers no N-type a me LED, e hōʻailona ana i ka hoʻomaka ʻana o ka 8-inch SiC substrate wafers ma ka mākeke.
Ma 2016, hoʻomaka ʻo Romm e kākoʻo i ka hui Venturi a ʻo ia ka mea mua i hoʻohana i ka hui IGBT + SiC SBD i loko o ke kaʻa e hoʻololi i ka hopena IGBT + Si FRD i ka inverter kuʻuna 200 kW. Ma hope o ka hoʻomaikaʻi ʻana, hoʻemi ʻia ke kaumaha o ka inverter e 2 kg a hoʻemi ʻia ka nui e 19% ʻoiai e mālama ana i ka mana like.

Ma 2017, ma hope o ka hoʻokomo hou ʻana o SiC MOS + SiC SBD, ʻaʻole i hoʻemi ʻia ke kaumaha e 6 kg, akā ua hoʻemi ʻia ka nui e 43%, a ua hoʻonui ʻia ka mana inverter mai 200 kW a 220 kW.
Ma hope o ka hoʻohana ʻana o Tesla i nā polokalamu SIC i nā mea hoʻohuli nui o kāna mau huahana Model 3 i 2018, ua hoʻonui wikiwiki ʻia ka hopena hōʻikeʻike, e hoʻolilo koke i ka mākeke automotive xEV i kumu o ka hauʻoli no ka mākeke SiC. Me ka hoʻohana kūleʻa ʻana o SiC, ua piʻi wikiwiki aʻe ka waiwai o ka mākeke pili.

ʻEiwa, Manaʻo:

Me ka hoʻomaikaʻi mau ʻana o nā ʻenehana ʻoihana pili i ka SiC, e hoʻomaikaʻi hou ʻia kona hua a me ka hilinaʻi, e hoʻemi ʻia ke kumukūʻai o nā mea SiC, a ʻike ʻia ka hoʻokūkū mākeke o SiC. I ka wā e hiki mai ana, e hoʻohana nui ʻia nā mea SiC i nā ʻano like ʻole e like me nā kaʻa, kamaʻilio, nā mana mana, a me ka lawe ʻana, a ʻoi aku ka laulā o ka mākeke huahana, a e hoʻonui ʻia ka nui o ka mākeke, e lilo i kākoʻo nui no ka lāhui. hoʻokele waiwai.