N'ime usoro uto kristal silicon carbide, njem ikuku anụ ahụ bụ usoro mmepụta ihe bụ isi ugbu a. Maka usoro uto PVT,silicon carbide ntụ ntụnwere mmetụta dị ukwuu na usoro uto. All paramita nkesilicon carbide ntụ ntụozugbo na-emetụta àgwà nke otu kristal uto na eletriki Njirimara. Na ngwa mmepụta ihe ugbu a, nke a na-ejikarị eme ihesilicon carbide ntụ ntụsynthesis usoro bụ onwe-agbasa elu-okpomọkụ njikọ usoro.
The onwe-propagating elu okpomọkụ synthesis usoro na-eji elu okpomọkụ na-enye reactants mbụ okpomọkụ na-amalite kemịkalụ mmeghachi omume, na mgbe ahụ na-eji ya chemical mmeghachi omume okpomọkụ na-ekwe ka unreacted bekee na-anọgide na-emecha kemịkalụ mmeghachi omume. Otú ọ dị, ebe mmeghachi omume kemịkal nke Si na C na-ewepụta obere okpomọkụ, a ghaghị ịgbakwunye ihe ndị ọzọ na-emeghachi omume iji nọgide na-enwe mmeghachi omume ahụ. Ya mere, ọtụtụ ndị ọkà mmụta atụpụtawo usoro mgbasa ozi onwe onye ka mma na ndabere a, na-ewebata onye na-arụ ọrụ. Usoro ịgbasa onwe ya dị mfe iji mejuputa ya, yana paramita njikọ dị iche iche dị mfe ijikwa nke ọma. Nkwekọrịta buru ibu na-egbo mkpa nke mmepụta ihe.
N'ihe dị ka afọ 1999, Bridgeport ji usoro nhazi okpomọkụ dị elu nke na-agbasa onwe ya.SiC ntụ ntụ, ma ọ na-eji ethoxysilane na phenol resin mee ihe dị ka akụrụngwa, nke dị oke ọnụ. Gao Pan na ndị ọzọ na-eji ntụ ntụ dị elu Si ntụ ntụ na C ntụ ntụ dị ka ihe eji eme iheSiC ntụ ntụsite na mmeghachi omume okpomọkụ dị elu na ikuku argon. Ning Lina kwadebere nnukwu urughuruSiC ntụ ntụsite na nke abụọ njikọ.
Ọkụ ọkụ induction ugboro ugboro nke ụlọ ọrụ nyocha nke abụọ nke China Electronics Technology Group Corporation mepụtara na-agwakọta ntụ ntụ silicon na ntụ ntụ carbon n'otu akụkụ stoichiometric ma tinye ha n'ime mkpọ graphite. Nkegraphite cruciblea na-etinye n'ime ọkụ ọkụ induction na-ekpo ọkụ maka ikpo ọkụ, a na-ejikwa mgbanwe okpomọkụ na-emepụta ma gbanwee usoro okpomọkụ dị ala na nnukwu okpomọkụ silicon carbide n'otu n'otu. Ebe ọ bụ na okpomọkụ nke mmeghachi omume β-SiC na-emeghachi omume na obere okpomọkụ dị ala karịa okpomọkụ nke volatilization nke Si, njikọ nke β-SiC n'okpuru nnukwu oghere nwere ike hụ na mgbasa nke onwe ya. Usoro nke iwebata argon, hydrogen na HCl gas na njikọ nke α-SiC na-egbochi ire ere.SiC ntụ ntụna ọnọdụ okpomọkụ dị elu, ma nwee ike ibelata ọdịnaya nitrogen na ntụ ntụ α-SiC.
Shandong Tianyue haziri ọkụ njikọ, na-eji silane gas dị ka silicon akụrụngwa na carbon ntụ ntụ dị ka carbon akụrụngwa. A na-ahazi ọnụọgụ gas nke akụrụngwa ewepụtara site na usoro nhazi nzọụkwụ abụọ, na nha nha nke silicon carbide ikpeazụ arụpụtara dị n'etiti 50 na 5 000 um.
1 Ihe nchịkwa nke usoro nchịkọta ntụ ntụ
1.1 Mmetụta nke ntụ ntụ ntụ ntụ na uto kristal
Oke urughuru nke silicon carbide ntụ ntụ nwere mmetụta dị oke mkpa na uto otu kristal na-esote. A na-enweta uto nke SiC otu kristal site na usoro PVT site n'ịgbanwe nha molar nke silicon na carbon na akụkụ gas gas, yana akụkụ molar nke silicon na carbon na akụkụ gas gas na-emetụta nha nke silicon carbide ntụ ntụ. . Mkpokọta nrụgide na silicon-carbon ruru nke usoro uto na-abawanye na mbelata nke urughuru nha. Mgbe nha nha na-ebelata site na 2-3 mm ruo 0.06 mm, nha silicon-carbon na-abawanye site na 1.3 ruo 4.0. Mgbe ihe ndị ahụ dị ntakịrị ruo n'ókè ụfọdụ, nrụgide akụkụ Si na-abawanye, na oyi akwa nke ihe nkiri Si na-etolite n'elu kristal na-eto eto, na-eme ka gas-mmiri siri ike na-eto eto, nke na-emetụta polymorphism, ntụpọ ntụpọ na ntụpọ ahịrị. na kristal. Ya mere, urughuru size nke elu-ọcha silicon carbide ntụ ntụ ga-mma na-achịkwa nke ọma.
Tụkwasị na nke ahụ, mgbe nha nke SiC ntụ ntụ dị ntakịrị, ntụ ntụ na-emebi ngwa ngwa, na-ebute oke uto nke otu kristal SiC. N'otu aka ahụ, na gburugburu ebe okpomọkụ dị elu nke SiC otu kristal na-eto eto, a na-eme usoro abụọ nke njikọ na decomposition n'otu oge. Silicon carbide ntụ ntụ ga-emebi ma mepụta carbon n'ime oge gas na usoro siri ike dị ka Si, Si2C, SiC2, na-eme ka carbonization siri ike nke polycrystalline ntụ ntụ na ịmepụta carbon inclusions na crystal; N'aka nke ọzọ, mgbe ọnụ ọgụgụ nbibi nke ntụ ntụ dị ngwa ngwa, usoro kristal nke otu kristal SiC toro eto na-adịkarị mfe ịgbanwe, na-eme ka o sie ike ịchịkwa àgwà nke otu kristal SiC toro eto.
1.2 Mmetụta nke ụdị kristal ntụ ntụ na uto kristal
Uto nke SiC otu kristal site na usoro PVT bụ usoro ngbanwe-recrystallization na oke okpomọkụ. Ụdị kristal nke SiC akụrụngwa nwere mmetụta dị mkpa na uto kristal. N'ime usoro nchịkọta ntụ ntụ, a ga-emepụta usoro nhazi nke dị ala (β-SiC) nke nwere akụkụ cubic nke cell unit na usoro okpomọkụ dị elu (α-SiC) nke nwere usoro hexagonal nke cell unit ga-emepụta tumadi. . Enwere ọtụtụ ụdị kristal silicon carbide na oke njikwa okpomọkụ dị warara. Dịka ọmụmaatụ, 3C-SiC ga-agbanwe ka ọ bụrụ silicon carbide polymorph hexagonal, ntụgharị 4H/6H-SiC, na okpomọkụ karịa 1900°C.
N'ime otu usoro uto kristal, mgbe a na-eji ntụ ntụ β-SiC na-eto kristal, ọnụọgụ silicon-carbon molar karịrị 5.5, ebe mgbe a na-eji ntụ ntụ α-SiC na-eto kristal, ọnụọgụ silicon-carbon molar bụ 1.2. Mgbe okpomọkụ na-ebili, mgbanwe nke usoro na-eme na crucible. N'oge a, molar ratio na gas na-aghọ ibu ibu, nke na-adịghị eme ka kristal na-eto eto. Na mgbakwunye, ihe adịghị ọcha nke gas ndị ọzọ, gụnyere carbon, silicon, na silicon dioxide, na-emepụta ngwa ngwa n'oge usoro mgbanwe nke oge. Ọnụnọ nke adịghị ọcha ndị a na-eme ka kristal na-amụba microtubes na oghere. Ya mere, a ghaghị ịchịkwa ụdị kristal ntụ ntụ nke ọma.
1.3 Mmetụta nke adịghị ọcha ntụ ntụ na uto kristal
Ọdịnaya adịghị ọcha dị na ntụ ntụ SiC na-emetụta nucleation na-enweghị onwe ya n'oge uto kristal. Ka ọdịnaya adịghị ọcha na-adị elu, ọ ga-abụkwa na ọ ga-abụ na kristal na-agbaji ozugbo. Maka SiC, isi ihe na-adịghị ọcha na-agụnye B, Al, V, na Ni, nke nwere ike ịmepụta site na ngwaọrụ nhazi n'oge nhazi nke silicon ntụ ntụ na carbon ntụ ntụ. N'ime ha, B na Al bụ ndị na-anabata ọkwa ike na-adịghị adị na SiC, na-ebute mbelata na mgbochi SiC. Ndị ọzọ na-adịghị ọcha ígwè ga-ewebata ọtụtụ ike ike, na-akpata na-ejighị n'aka eletriki Njirimara nke SiC otu kristal na elu okpomọkụ, na-enwe mmetụta dị ukwuu na eletriki Njirimara nke elu-ọcha ọkara ikpuchi otu kristal substrates, karịsịa resistivity. Ya mere, a ghaghị ijikọta ntụ ntụ silicon carbide dị ọcha dị ka o kwere mee.
1.4 Mmetụta nke ọdịnaya nitrogen na ntụ ntụ na uto kristal
Ọkwa nke ọdịnaya nitrogen na-ekpebi ihe mgbochi nke otu mkpụrụ kristal. Ndị na-emepụta ihe dị mkpa kwesịrị ịhazigharị mkpokọta doping nitrogen na ihe sịntetik dịka usoro uto kristal tozuru oke n'oge njikọ ntụ ntụ. Otu mkpụrụ kristal silicon carbide dị elu nke na-adị ọcha bụ ihe kacha ekwe nkwa maka akụrụngwa elektrọnik isi ndị agha. Iji too elu-ọcha ọkara mkpuchi otu mkpụrụ kristal nwere nnukwu resistivity na ezigbo ọkụ eletrik, ọdịnaya nke nitrogen adịghị ọcha na mkpụrụ ga-enwerịrị ike ịchịkwa ya na ọkwa dị ala. Otu mkpụrụ kristal na-arụ ọrụ chọrọ ka a chịkwaa ọdịnaya nitrogen n'ogo dị elu.
2 Teknụzụ njikwa igodo maka njikọ ntụ ntụ
N'ihi gburugburu ojiji dị iche iche nke silicon carbide substrates, teknụzụ njikọ maka uto powders nwekwara usoro dị iche iche. Maka ụdị N-eduzi otu ntụ ntụ kristal, ịdị ọcha dị elu na otu akụkụ ka achọrọ; ebe maka ọkara mkpuchi otu ntụ ntụ uto kristal, njikwa siri ike nke ọdịnaya nitrogen chọrọ.
2.1 njikwa nha nha ntụ ntụ
2.1.1 Synthesis okpomọkụ
Idebe usoro usoro ndị ọzọ agbanweghị, SiC powders emepụtara na okpomọkụ nke 1900 ℃, 2000 ℃, 2100 ℃, na 2200 ℃ e sampled na nyochaa. Dị ka e gosiri na Figure 1, ọ pụrụ ịhụ na urughuru size bụ 250 ~ 600 μm na 1900 ℃, na urughuru size na-abawanye na 600 ~ 850 μm na 2000 ℃, na urughuru size mgbanwe budata. Mgbe okpomọkụ na-aga n'ihu na-ebili na 2100 ℃, nha nha nke SiC ntụ ntụ bụ 850 ~ 2360 μm, mmụba na-eme ka ọ dị nro. Ogo urughuru SiC na 2200 ℃ kwụsiri ike na ihe dịka 2360 μm. Mmụba nke njikọ okpomọkụ sitere na 1900 ℃ nwere mmetụta dị mma na nha nha nke SiC. Mgbe njikọ okpomọkụ na-aga n'ihu na-abawanye site na 2100 ℃, urughuru size agaghịkwa agbanwe nke ukwuu. Ya mere, mgbe njikọ okpomọkụ atọrọ ka 2100 ℃, a ibu urughuru size nwere ike synthesized na a ala ike oriri.
2.1.2 Oge nchịkọta
Ọnọdụ usoro ndị ọzọ na-agbanwe agbanwe, na oge nhazi ahụ ka edobere 4 h, 8h, na 12 h n'otu n'otu. A na-egosi nyocha ihe nlele nke SiC ntụ ntụ na-egosi na eserese 2. Achọpụtara na oge njikọ ahụ nwere mmetụta dị ịrịba ama na nha nha nke SiC. Mgbe oge njikọ bụ 4 h, a na-ekesa oke nha na 200 μm; mgbe oge njikọ ahụ bụ 8 h, nha nha nke sịntetik na-abawanye nke ukwuu, na-ekesa na ihe dịka 1 000 μm; ka njikọ oge na-aga n'ihu na-abawanye, urughuru size na-abawanye n'ihu, tumadi kesara na banyere 2 000 μm.
2.1.3 Mmetụta nke akụrụngwa akụrụngwa nha
Ka a na-eji nke nta nke nta na-emewanye ụdọ mmepụta ihe silicon ụlọ, ịdị ọcha nke ihe silicon na-emekwa ka ọ dịkwuo mma. Ka ọ dị ugbu a, a na-ekewa ihe ndị a na-eji eme ihe na synthesis na silicon granular na silicon powdered, dị ka egosiri na foto 3.
A na-eji akụrụngwa silicon dị iche iche mee nnwale njikọ nke silicon carbide. E gosipụtara ntụnyere nke ngwaahịa sịntetik na eserese 4. Nnyocha na-egosi na mgbe ị na-eji ihe mgbochi silicon akụrụngwa, nnukwu ihe Si dị na ngwaahịa ahụ. Mgbe e gwepịasịrị ngọngọ silicon nke ugboro abụọ, ihe Si element na ngwaahịa sịntetik na-ebelata nke ukwuu, mana ọ ka dị. N'ikpeazụ, a na-eji ntụ ntụ silicon eme ihe maka njikọ, na naanị SiC dị na ngwaahịa ahụ. Nke a bụ n'ihi na na mmepụta usoro, nnukwu-size granular silicon kwesịrị ịmalite mmeghachi omume n'elu, na silicon carbide na-emepụta n'elu, nke na-egbochi n'ime ime ntụ ntụ si n'ihu ijikọta na C ntụ ntụ. Ya mere, ọ bụrụ na a na-eji silicon mgbochi eme ihe dị ka ihe eji eme ihe, ọ dị mkpa ka a gwerie ya wee tinye usoro nhazi nke abụọ iji nweta silicon carbide ntụ ntụ maka uto kristal.
2.2 njikwa ụdị kristal ntụ ntụ
2.2.1 Mmetụta nke njikọ okpomọkụ
Ịnọgide na-enwe ọnọdụ usoro ndị ọzọ na-agbanweghị, ọnọdụ okpomọkụ nke njikọ bụ 1500 ℃, 1700 ℃, 1900 ℃, na 2100 ℃, na-emepụta ntụ ntụ SiC na-enyocha ma nyochaa. Dị ka e gosiri na foto 5, β-SiC bụ odo ájá ájá, na α-SiC dị ọkụ na agba. Site n'ikiri agba na morphology nke ntụ ntụ synthesized, enwere ike ikpebi na ngwaahịa synthesized bụ β-SiC na okpomọkụ nke 1500 ℃ na 1700 ℃. Na 1900 ℃, agba na-aghọ ọkụ, na hexagonal irighiri pụtara, na-egosi na mgbe okpomọkụ adahade 1900 ℃, a na-adọ mgbanwe na-eme, na akụkụ nke β-SiC converted n'ime α-SiC; mgbe okpomọkụ na-aga n'ihu na-ebili ruo 2100 ℃, a na-achọpụta na ihe ndị a na-emepụta na-apụta ìhè, na α-SiC agbanweela.
2.2.2 Mmetụta nke oge njikọ
Ọnọdụ usoro ndị ọzọ na-agbanweghị, na oge nhazi ahụ ka edobere na 4h, 8h, na 12h, n'otu n'otu. A na-enyocha ntụ ntụ SiC emepụtara wee nyochaa ya site na diffractometer (XRD). E gosipụtara nsonaazụ ya na eserese 6. Oge nchịkọta nwere mmetụta ụfọdụ na ngwaahịa nke SiC ntụ ntụ mebere. Mgbe oge njikọ bụ 4 h na 8 h, ngwaahịa sịntetik bụ tumadi 6H-SiC; mgbe oge njikọ bụ 12 h, 15R-SiC pụtara na ngwaahịa.
2.2.3 Mmetụta nke akụrụngwa akụrụngwa
Usoro ndị ọzọ na-agbanweghị agbanwe, a na-enyocha ọnụọgụ silicon-carbon, na nha bụ 1.00, 1.05, 1.10 na 1.15 n'otu n'otu maka nyocha njikọ. E gosipụtara nsonaazụ ya na eserese 7.
Site na XRD ụdịdị dị iche iche, enwere ike ịhụ na mgbe ọnụọgụ silicon-carbon karịrị 1.05, ngafe Si na-apụta na ngwaahịa a, na mgbe oke silicon-carbon erughị 1.05, ngafe C na-apụta. Mgbe nha silicon-carbon bụ 1.05, carbon free na ngwaahịa sịntetik na-ekpochapụ kpamkpam, ọ nweghị silicon na-apụta. Ya mere, oke nha nke silicon-carbon ruru kwesịrị ịbụ 1.05 iji mepụta SiC dị ọcha.
2.3 Njikwa ọdịnaya nitrogen dị na ntụ ntụ
2.3.1 sịntetik akụrụngwa
Ngwa ngwa eji eme nnwale a bụ ntụ ntụ carbon dị ọcha na ntụ ntụ silicon dị elu nke nwere dayameta etiti nke 20 μm. N'ihi na ha obere urughuru size na nnukwu kpọmkwem n'elu ebe, ha dị mfe itinye N2 na ikuku. Mgbe ị na-emepụta ntụ ntụ, a ga-ebute ya n'ụdị kristal nke ntụ ntụ. Maka uto nke ụdị kristal N, doping na-ezighi ezi nke N2 na ntụ ntụ na-eduga na nguzogide na-enweghị isi nke kristal na ọbụna mgbanwe n'ụdị kristal. Ọdịnaya nitrogen nke ntụ ntụ synthesized mgbe ewebatara hydrogen dị obere. Nke a bụ n'ihi na olu nke molekul hydrogen dị ntakịrị. Mgbe N2 adsorbed na carbon ntụ ntụ na silicon ntụ ntụ na-ekpo ọkụ ma na-esi n'elu, H2 na-agbasa n'ụzọ zuru ezu n'ime oghere dị n'etiti powders na obere olu ya, na-edochi ọnọdụ N2, na N2 na-agbapụ na crucible n'oge usoro agụụ. imezu ebumnuche iwepu ọdịnaya nitrogen.
2.3.2 Usoro nhazi
N'oge njikọ nke silicon carbide ntụ ntụ, ebe ọ bụ na radius nke carbon atom na nitrogen atom yiri, nitrogen ga-anọchi carbon oghere na silicon carbide, si otú na-amụba nitrogen ọdịnaya. Usoro nnwale a na-anabata usoro iwebata H2, na H2 na-emeghachi omume na ihe carbon na silicon na njikọ crucible iji mepụta gas C2H2, C2H, na SiH. Ọdịnaya carbon element na-abawanye site na nnyefe oge gas, si otú a na-ebelata ohere ikuku carbon. A na-enweta ebumnuche nke iwepụ nitrogen.
2.3.3 Usoro njikwa ọdịnaya nitrogen ndabere
Enwere ike iji eriri graphite nwere nnukwu porosity dị ka isi mmalite C ọzọ iji banye Si vapor n'ime akụkụ akụkụ gas, belata Si na akụkụ gas, wee si otú a na-abawanye C / Si. N'otu oge ahụ, graphite crucibles nwekwara ike imeghachi omume na ikuku Si iji mepụta Si2C, SiC2 na SiC, nke kwekọrọ na ikuku SiC na-ebute isi iyi C sitere na graphite crucible n'ime ikuku uto, na-abawanye oke C, yana ịbawanye oke carbon-silicon. . Ya mere, enwere ike ịbawanye oke carbon-silicon site na iji graphite crucibles nwere nnukwu porosity, ibelata ohere ikuku carbon, na imezu ebumnuche iwepu nitrogen.
3 Nyocha na imewe nke otu kristal ntụ ntụ usoro
3.1 Ụkpụrụ na imewe nke usoro njikọ
Site na n'elu-e kwuru keukwu ọmụmụ na-achịkwa nke urughuru size, crystal ụdị na nitrogen ọdịnaya nke ntụ ntụ synthesis, a njikọ usoro a tụrụ aro. A na-ahọrọ ntụ ntụ C dị elu na Si ntụ ntụ, a na-agwakọta ha nke ọma ma tinye ya na graphite crucible dị ka ọnụọgụ silicon-carbon nke 1.05. A na-ekewa usoro usoro a ụzọ anọ:
1) Usoro denitrification nke dị ala, na-ekpochapụ na 5 × 10-4 Pa, wee webata hydrogen, na-eme ka ụlọ ahụ dị ka 80 kPa, na-ejigide 15 min, na-emegharị ugboro anọ. Usoro a nwere ike wepụ ihe nitrogen dị n'elu carbon ntụ ntụ na silicon ntụ ntụ.
2) Usoro denitrification nke okpomọkụ dị elu, na-ekpo ọkụ na 5 × 10-4 Pa, wee kpoo ọkụ na 950 ℃, wee webata hydrogen, na-eme ka ụlọ ahụ na-arụ ọrụ dị ka 80 kPa, na-ejigide 15 min, na-emegharị ugboro anọ. Usoro a nwere ike wepu ihe nitrogen dị n'elu carbon ntụ ntụ na silicon ntụ ntụ, ma mee ka nitrogen dị n'ọhịa okpomọkụ.
3) Synthesis nke usoro usoro okpomọkụ dị ala, pụọ na 5 × 10-4 Pa, wee kpoo ọkụ ruo 1350 ℃, debe maka awa 12, wee webata hydrogen iji mee ka ọnụ ụlọ ahụ dị ihe dịka 80 kPa, debe maka 1 hour. Usoro a nwere ike wepụ nitrogen na-agbanwe agbanwe n'oge usoro njikọ.
4) Synthesis nke elu okpomọkụ usoro usoro, jupụta na ụfọdụ gas olu eruba ruru nke elu ịdị ọcha hydrogen na argon agwakọta gas, ime ka ụlọ mgbali banyere 80 kPa, welie okpomọkụ ka 2100 ℃, na-na 10 awa. Usoro a na-emecha ngbanwe nke silicon carbide ntụ ntụ site na β-SiC ruo α-SiC ma mechaa uto nke kristal.
N'ikpeazụ, chere ka ọnụ ụlọ ahụ dị jụụ ruo n'ime ụlọ, jupụta na nrụgide ikuku, ma wepụ ntụ ntụ.
3.2 Usoro nhazi nhazi nke ntụ ntụ
Mgbe emechara ntụ ntụ site na usoro a dị n'elu, a ga-edozirịrị ya iji wepụ carbon n'efu, silicon na adịghị ọcha ndị ọzọ na ihuenyo nha. Nke mbụ, a na-etinye ntụ ntụ synthesized n'ime igwe ihe igwe maka ịkụpịa, a na-etinye ntụ ntụ silicon carbide na-egweri n'ime ọkụ muffle ma kpoo ọkụ ruo 450 ° C site na ikuku oxygen. Carbon efu na ntụ ntụ na-ekpo ọkụ na-ekpo ọkụ iji mepụta carbon dioxide gas nke na-esi na ụlọ ahụ pụta, si otú a na-enweta mwepụ nke carbon free. Mgbe nke ahụ gasịrị, a na-edozi mmiri mmiri na-ehicha acidic ma tinye ya n'ime igwe na-ehicha ihe dị na silicon carbide maka ihicha iji wepụ carbon, silicon na metal adịghị ọcha emepụtara n'oge usoro nhazi. Mgbe nke ahụ gasịrị, a na-asacha acid fọdụrụnụ na mmiri dị ọcha ma kpoo ya. A na-ekpuchi ntụ ntụ a mịrị amị na ihuenyo na-ama jijiji maka oke nha nha maka uto kristal.
Oge nzipu: Ọgọst-08-2024