Munzira yekukura kwesilicon carbide single crystal, kutakurwa kwemhepo inofema ndiyo nzira huru yekuvandudza maindasitiri. Kune nzira yekukura yePVT,upfu hwesilicon carbideine simba guru pakukura kwemuti. Zvose zvinodiwa pakukura kwemutiupfu hwesilicon carbidezvinokanganisa zvakananga kunaka kwekukura kwekristaro imwe chete uye hunhu hwemagetsi. Mukushandiswa kwemaindasitiri pari zvino, zvinowanzoshandiswaupfu hwesilicon carbideMaitiro ekugadzira ndiyo nzira yekugadzira inobereka yega-inodziya zvakanyanya.
Nzira yekuzviparadzira inodziparadzira inoshandisa tembiricha yepamusoro kupa reactants kupisa kwekutanga kutanga maitiro emakemikari, uye yobva yashandisa kupisa kwayo kwemakemikari kuti zvinhu zvisina kugadziriswa zvirambe zvichipedzisa maitiro emakemikari. Zvisinei, sezvo maitiro emakemikari eSi neC achiburitsa kupisa kushoma, mamwe maitiro anofanirwa kuwedzerwa kuti arambe achienderera mberi nemaitiro acho. Nokudaro, nyanzvi dzakawanda dzakapa nzira yakagadziriswa yekugadzira inodziparadzira pachayo pahwaro uhwu, dzichiisa activator. Nzira yekuzviparadzira iri nyore kushandisa, uye maparamendi akasiyana-siyana ekugadzira ari nyore kudzora. Kugadzira kukuru kunosangana nezvinodiwa zvemaindasitiri.
Kare muna 1999, Bridgeport yakashandisa nzira yekuzvigadzira inopararira nekupisa kwakanyanya kuti igadzireUpfu hweSiC, asi yakashandisa ethoxysilane nephenol resin sezvinhu zvekugadzira, izvo zvaidhura. Gao Pan nevamwe vakashandisa upfu hweSi hwakachena uye upfu hweC hwakanyanya sezvinhu zvekugadzira.Upfu hweSiCnekuita kwekupisa kwakanyanya mumhepo ine argon. Ning Lina akagadzira zvidimbu zvikuruUpfu hweSiCkuburikidza nekugadzirwa kwechipiri.
Chitofu chekupisa chepakati-frequency induction chakagadzirwa neSecond Research Institute of China Electronics Technology Group Corporation chinosanganisa zvakaenzana upfu hwesilicon necarbon powder mune imwe stoichiometric ratio uye chinozviisa mu graphite crucible.chipfuro chegrafitiinoiswa muchoto chekupisa chepakati-frequency induction kuti chidziye, uye shanduko yekushisa inoshandiswa kugadzira nekushandura chikamu chekupisa chakaderera uye chikamu chekupisa chakakwirira chesilicon carbide zvakateerana. Sezvo tembiricha ye β-SiC synthesis reaction muchikamu chekupisa chakaderera yakaderera pane tembiricha ye volatilization yeSi, kugadzirwa kwe β-SiC pasi pe high vacuum kunogona kuve nechokwadi chekuti inozviparadzira. Nzira yekuunza argon, hydrogen uye HCl gas mukugadzirwa kwe α-SiC inodzivirira kuora kweUpfu hweSiCmuchikamu chekupisa kwakanyanya, uye zvinogona kuderedza huwandu hwenitrogen muupfu hweα-SiC zvinobudirira.
Shandong Tianyue yakagadzira furnace yekugadzira, ichishandisa gasi resilane sesilicon raw material uye kabhoni powder secarbon raw material. Huwandu hwegasi rezvinhu zvisina kugadzirwa hwakagadziriswa nenzira yekugadzira ine matanho maviri, uye saizi yekupedzisira yesilicon carbide yakagadzirwa yaive pakati pe50 ne5000 um.
1 Zvinhu zvinodzora mashandiro ekugadzira hupfu
1.1 Mhedzisiro yehukuru hwezvimedu zveupfu pakukura kwekristaro
Saizi yesilicon carbide powder ine simba guru pakukura kwekristaro imwe chete. Kukura kweSiC single crystal nePVT method kunonyanya kuwanikwa nekushandura molar ratio yesilicon nekabhoni muchikamu chegasi, uye molar ratio yesilicon nekabhoni muchikamu chegasi ine chekuita nehukuru hwesilicon carbide powder. Kumanikidzwa kwese uye silicon-carbon ratio yekukura kwesystem inowedzera nekudzikira kwehukuru hweparticle. Kana saizi yeparticle yadzikira kubva pa2-3 mm kusvika pa0.06 mm, silicon-carbon ratio inowedzera kubva pa1.3 kusvika pa4.0. Kana particles dziri diki kusvika pamwero wakati, Si partial pressure inowedzera, uye layer yeSi film inoumbwa pamusoro pekristaro iri kukura, zvichikonzera kukura kwegasi-liquid-solid, izvo zvinokanganisa polymorphism, point defects uye line defects mukristaro. Nokudaro, saizi yeparticle yehigh-purity silicon carbide powder inofanira kudzorwa zvakanaka.
Pamusoro pezvo, kana saizi yezvikamu zveupfu hweSiC iri diki, upfu hunoora nekukurumidza, zvichikonzera kukura kwakanyanya kweSiC single crystals. Kune rumwe rutivi, munzvimbo inodziya zvakanyanya yekukura kweSiC single crystal, maitiro maviri ekugadzira nekuora anoitwa panguva imwe chete. Upfu hweSilicon carbide hunoora uye hunogadzira kabhoni muchikamu chegasi nechikamu chakasimba senge Si, Si2C, SiC2, zvichikonzera carbonization yakakura yepolycrystalline powder uye kuumbwa kwecarbon inclusions mukristaro; kune rumwe rutivi, kana chiyero chekuora kweupfu chichikurumidza, chimiro chekristaro cheSiC single crystal chakakura chinogona kuchinja, zvichiita kuti zviome kudzora mhando yeSiC single crystal yakakura.
1.2 Mhedzisiro yechimiro chekristaro cheupfu pakukura kwekristaro
Kukura kweSiC single crystal nePVT method inzira ye sublimation-recrystallization process pakupisa kwakanyanya. Chimiro chekristaro cheSiC raw material chine simba guru pakukura kwekristaro. Mukuita kwekugadzirwa kweupfu, chikamu che low-temperature synthesis (β-SiC) chine chimiro che cubic che unit cell uye chikamu che high-temperature synthesis (α-SiC) chine chimiro che hexagonal che unit cell chichanyanya kugadzirwa. Kune akawanda ma silicon carbide crystal form uye diki temperature control range. Semuenzaniso, 3C-SiC ichashanduka kuita hexagonal silicon carbide polymorph, kureva 4H/6H-SiC, pakupisa kuri pamusoro pe 1900°C.
Munguva yekukura kwekristaro imwe chete, apo upfu hweβ-SiC hunoshandiswa kukura makristaro, chiyero chesilicon-carbon molar chinopfuura 5.5, nepo kana upfu hweα-SiC huchishandiswa kukura makristaro, chiyero chesilicon-carbon molar chinopfuura 1.2. Kana tembiricha yakwira, shanduko yechikamu inoitika mucrucible. Panguva ino, chiyero chemolar muchikamu chegasi chinokura, izvo zvisingakodzeri kukura kwekristaro. Pamusoro pezvo, kumwe kusvibiswa kwechikamu chegasi, kusanganisira kabhoni, silicon, uye silicon dioxide, kunogadzirwa zviri nyore panguva yekuchinja kwechikamu. Kuvapo kwetsvina iyi kunoita kuti kristaro ibereke ma microtubes nema voids. Nokudaro, chimiro chekristaro cheupfu chinofanira kudzorwa nemazvo.
1.3 Mhedzisiro yetsvina yeupfu pakukura kwekristaro
Kusvibiswa kuri muupfu hweSiC kunokanganisa nucleation inongoerekana yaitika panguva yekukura kwekristaro. Kana kusvibiswa kwacho kwakakwira, mukana wekuti kristaro iite nucleate inongoerekana yaitika. Kune SiC, kusvibiswa kukuru kwesimbi kunosanganisira B, Al, V, naNi, izvo zvinogona kuunzwa nezvishandiso zvekugadzirisa panguva yekugadzirisa silicon powder necarbon powder. Pakati pazvo, B naAl ndiwo kusvibiswa kukuru kwesimba remagetsi muSiC, zvichikonzera kudzikira kweSiC resistivity. Kumwe kusvibiswa kwesimbi kuchaunza mazinga akawanda esimba, zvichikonzera kusagadzikana kwemagetsi emakristaro eSiC single pakupisa kwakanyanya, uye zvine simba guru pamasimba emagetsi emakristaro epamusoro-purity semi-insulating single crystal substrates, kunyanya resistivity. Naizvozvo, high-purity silicon carbide powder inofanira kugadzirwa zvakanyanya sezvinobvira.
1.4 Mhedzisiro yehuwandu hwenitrogen muupfu pakukura kwekristaro
Kuwanda kwenitrogen kunosarudza resistivity ye single crystal substrate. Vagadziri vakuru vanofanirwa kugadzirisa huwandu hwenitrogen doping muzvinhu zvakagadzirwa zvichienderana nekukura kwecrystal panguva yekugadzira upfu. High-purity semi-insulating silicon carbide single crystal substrates ndiyo inonyanya kuvimbisa zvikamu zvemagetsi zvemauto. Kuti ukure high-purity semi-insulating single crystal substrates ine resistivity yakakwira uye hunhu hwakanaka hwemagetsi, huwandu hwenitrogen huru isina kuchena mu substrate hunofanira kudzorwa padanho rakaderera. Conductive single crystal substrates inoda kuti nitrogen ive nehuwandu hwakanyanya.
2 Tekinoroji huru yekudzora kugadzirwa kwehupfu
Nekuda kwenzvimbo dzakasiyana dzekushandiswa kwe silicon carbide substrates, tekinoroji yekugadzira hupfu hwekukura ine maitiro akasiyana. Kune hupfu hwekukura hwemhando yeN-type conductive single crystal, kuchena kwakanyanya uye single phase zvinodiwa; nepo kune hupfu hwekukura hwemakristaro ehafu-insulating, kudzora kwakasimba kwehuwandu hwenitrogen kunodiwa.
2.1 Kudzora saizi yehupfu
2.1.1 Tembiricha yekugadzira
Zvichichengetedza mamwe mamiriro ezvinhu asina kuchinja, upfu hweSiC hunogadzirwa patembiricha yekugadzira ye1900 ℃, 2000 ℃, 2100 ℃, uye 2200 ℃ hwakatorwa sampuli uye hwakaongororwa. Sezvakaratidzwa muMufananidzo 1, zvinogona kuonekwa kuti saizi yezvikamu ndeye 250~600 μm pa1900 ℃, uye saizi yezvikamu inowedzera kusvika 600~850 μm pa2000 ℃, uye saizi yezvikamu inochinja zvakanyanya. Kana tembiricha ikaramba ichikwira kusvika 2100 ℃, saizi yezvikamu yeupfu hweSiC ndeye 850~2360 μm, uye kuwedzera kunowanzova kunyoro. Saizi yezvikamu yeSiC pa2200 ℃ yakagadzikana painenge 2360 μm. Kuwedzera kwetembiricha yekugadzira kubva pa1900 ℃ kune mhedzisiro yakanaka pahukuru hwezvikamu zveSiC. Kana tembiricha yekugadzira ikaramba ichikwira kubva pa2100 ℃, saizi yezvikamu haichachinje zvakanyanya. Saka, kana tembiricha yekugadzira yaiswa pa2100 ℃, saizi huru yezvikamu inogona kugadzirwa nekushandiswa kwesimba kwakaderera.
2.1.2 Nguva yekugadzira
Mamwe mamiriro ezvinhu ekushanda anoramba asina kuchinja, uye nguva yekugadzira yakagadzirwa kusvika maawa mana, maawa masere, uye maawa gumi nemaviri zvichiteerana. Kuongororwa kweSiC powder sampling yakagadzirwa kunoratidzwa muMufananidzo 2. Zvakaonekwa kuti nguva yekugadzira ine mhedzisiro yakakura pahukuru hwezvikamu zveSiC. Kana nguva yekugadzira iri maawa mana, hukuru hwezvikamu hunonyanya kugoverwa pa200 μm; kana nguva yekugadzira iri maawa masere, hukuru hwezvikamu zvekugadzira hunowedzera zvakanyanya, hunonyanya kugoverwa pa1 000 μm; sezvo nguva yekugadzira ichiramba ichiwedzera, hukuru hwezvikamu hunowedzera zvakanyanya, hunonyanya kugoverwa pa2 000 μm.
2.1.3 Simba rehukuru hwezvinhu zvakagadziriswa
Sezvo cheni yekugadzira zvinhu zvesilicon yemumba ichivandudzwa zvishoma nezvishoma, kuchena kwezvinhu zvesilicon kuri kuvandudzwawo zvakanyanya. Parizvino, zvinhu zvesilicon zvinoshandiswa mukugadzira zvinhu zvakakamurwa kuita granular silicon nepowdered silicon, sezvakaratidzwa muMufananidzo 3.
Zvinhu zvakasiyana-siyana zvesilicon zvakashandiswa kuita kuyedza kwekugadzira silicon carbide. Kuenzanisa kwezvinhu zvakagadzirwa kunoratidzwa muMufananidzo 4. Ongororo inoratidza kuti kana uchishandisa zvinhu zvakagadzirwa nesilicon block, zvinhu zvakawanda zveSi zviripo muchigadzirwa. Mushure mekunge silicon block yapwanywa kechipiri, chinhu cheSi chiri muchigadzirwa chakagadzirwa chinoderedzwa zvakanyanya, asi chichiripo. Pakupedzisira, silicon powder inoshandiswa pakugadzira, uye SiC chete ndiyo iripo muchigadzirwa. Izvi zvinodaro nekuti mukugadzirwa, silicon yakakura inofanira kutanga yaitwa surface synthesis reaction, uye silicon carbide inogadzirwa pamusoro, izvo zvinodzivirira mukati meSi powder kuti isasanganiswe neC powder. Saka, kana block silicon ikashandiswa sezvinhu zvakagadzirwa, inoda kupwanywa uye yozoitwa secondary synthesis process kuti iwane silicon carbide powder yekukura kwekristaro.
2.2 Kudzora chimiro chekristaro cheupfu
2.2.1 Simba rekupisa kwekugadzira
Kuchengetedza mamwe mamiriro ezvinhu ekushanda kusina kuchinja, tembiricha yekugadzira ndeye 1500℃, 1700℃, 1900℃, uye 2100℃, uye upfu hweSiC hunogadzirwa hunotorwa uye hunoongororwa. Sezvakaratidzwa muMufananidzo 5, β-SiC ndeyero yevhu, uye α-SiC ine ruvara rwakajeka. Nekutarisa ruvara uye chimiro cheupfu hwakagadzirwa, zvinogona kuonekwa kuti chigadzirwa chakagadzirwa iβ-SiC patembiricha ye1500℃ ne1700℃. Pa1900℃, ruvara runova rwakajeka, uye zvidimbu zvehexagonal zvinoonekwa, zvichiratidza kuti mushure mekunge tembiricha yakwira kusvika 1900℃, kuchinja kwechikamu kunoitika, uye chikamu cheβ-SiC chinoshandurwa kuita α-SiC; kana tembiricha ikaramba ichikwira kusvika 2100℃, zvinowanikwa kuti zvidimbu zvakagadzirwa zvinopenya, uye α-SiC yave kushandurwa zvakanyanya.
2.2.2 Mhedzisiro yenguva yekugadzira
Mamwe mamiriro ezvinhu ekugadzirisa anoramba asina kuchinja, uye nguva yekugadzira yakaiswa kumaawa mana, maawa masere, uye maawa gumi nemaviri, zvichiteerana. Upfu hweSiC hunogadzirwa hunotorwa uye hunoongororwa ne diffractometer (XRD). Mhedzisiro yacho inoratidzwa muMufananidzo 6. Nguva yekugadzira ine simba rakati pane chigadzirwa chinogadzirwa neSiC powder. Kana nguva yekugadzira iri maawa mana uye maawa masere, chigadzirwa chekugadzira chinonyanya kuva 6H-SiC; kana nguva yekugadzira iri maawa gumi nemaviri, 15R-SiC inoonekwa muchigadzirwa.
2.2.3 Simba rehuwandu hwezvinhu zvakagadziriswa
Mamwe maitiro anoramba asina kuchinja, huwandu hwezvinhu zvesilicon-carbon hunoongororwa, uye zviyero zvacho zviri 1.00, 1.05, 1.10 uye 1.15 zvichiteerana pakuedza kwekugadzira. Mhedzisiro yacho inoratidzwa muMufananidzo 7.
Kubva pa XRD spectrum, zvinogona kuonekwa kuti kana chiyero chesilicon-carbon chakakura kupfuura 1.05, Si yakawandisa inoonekwa muchigadzirwa, uye kana chiyero chesilicon-carbon chiri pasi pe1.05, C yakawandisa inoonekwa. Kana chiyero chesilicon-carbon chiri 1.05, kabhoni yakasununguka muchigadzirwa chakagadzirwa inobviswa, uye hapana silicon yakasununguka inoonekwa. Nokudaro, chiyero chehuwandu hwesilicon-carbon chinofanira kuva 1.05 kugadzira SiC yakachena zvakanyanya.
2.3 Kudzora huwandu hushoma hwenitrogen muupfu
2.3.1 Zvinhu zvakagadzirwa nemakemikari
Zvinhu zvakashandiswa mukuyedza uku ihupfu hwekabhoni hwakachena uye hupfu hwesilicon hwakachena hune dhayamita yepakati ye20 μm. Nekuda kwehukuru hwadzo hudiki uye nzvimbo yakakura yekumusoro, zviri nyore kunyudza N2 mumhepo. Pakugadzira hupfu, hunounzwa muchimiro chekristaro chehupfu. Kuti makristaro erudzi rweN akure, kusaenzana kweN2 muhupfu kunotungamira kune kusaenzana kwekristaro uye kunyange kuchinja muchimiro chekristaro. nitrogen yehupfu hwakagadzirwa mushure mekunge hydrogen yaunzwa yakaderera zvakanyanya. Izvi zvinodaro nekuti huwandu hwemamorekuru ehydrogen hudiki. Kana N2 yakabatwa muhupfu hwekabhoni uye upfu hwesilicon yapiswa uye yaora kubva pamusoro, H2 inopararira zvizere mumukana uri pakati pehupfu nehuwandu hwayo hudiki, ichitsiva chinzvimbo cheN2, uye N2 inobuda mucrucible panguva yekubvisa vacuum, ichizadzisa chinangwa chekubvisa huwandu hwenitrogen.
2.3.2 Maitiro ekugadzira
Munguva yekugadzira upfu hwesilicon carbide, sezvo nzvimbo yemaatomu ekabhoni nemaatomu enitrogen yakafanana, nitrogen inotsiva nzvimbo dzisina kabhoni musilicon carbide, nokudaro ichiwedzera huwandu hwenitrogen. Maitiro aya ekuyedza anoshandisa nzira yekuunza H2, uye H2 inopindirana nezvinhu zvekabhoni nesilicon mu synthesis crucible kugadzira magasi eC2H2, C2H, uye SiH. Hunhu hwezvinhu zvekabhoni hunowedzera kuburikidza nekutapurirana kwegasi, nokudaro zvichideredza nzvimbo dzisina kabhoni. Chinangwa chekubvisa nitrogen chinozadzikiswa.
2.3.3 Kudzora huwandu hwenitrogen mumaitiro ekumashure
Zvigadziko zveGraphite zvine maburi makuru zvinogona kushandiswa semamwe manyuko eC ekupinza utsi hweSi muzvikamu zvegasi, kuderedza Si muzvikamu zvegasi, uye nokudaro kuwedzera C/Si. Panguva imwe chete, zvigadziko zveGraphite zvinogonawo kuita nemhepo yeSi kugadzira Si2C, SiC2 neSiC, izvo zvakaenzana nemhepo yeSi inoburitsa C kubva kuchikamu cheGraphite mumhepo yekukura, kuwedzera C ratio, uye kuwedzera carbon-silicon ratio. Nokudaro, chiyero checarbon-silicon chinogona kuwedzerwa nekushandisa zvigadziko zveGraphite zvine maburi makuru, kuderedza nzvimbo dzisina carbon, uye kuzadzisa chinangwa chekubvisa nitrogen.
3 Kuongorora nekugadzira maitiro ekugadzira upfu hwekristaro imwe chete
3.1 Nheyo uye dhizaini yemaitiro ekugadzira
Kuburikidza nekudzidza kwakazara kwataurwa pamusoro apa pamusoro pekudzora saizi yezvikamu, chimiro chekristaro uye huwandu hwenitrogen mukugadzirwa kweupfu, nzira yekugadzira inokurudzirwa. Upfu hweC hwakachena zvakanyanya neupfu hweSi zvinosarudzwa, uye zvinosanganiswa zvakaenzana uye zvinoiswa mu graphite crucible zvichienderana ne silicon-carbon ratio ye1.05. Matanho ekuita akakamurwa kuita zvikamu zvina:
1) Maitiro ekubvisa nitrogen pakupisa kwakaderera, kubvisa hydrogen kusvika pa5×10-4 Pa, wozoisa hydrogen, zvichiita kuti pressure yemukamuri isvike 80 kPa, kuchengetedza kwemaminitsi gumi nemashanu, uye kudzokorora kana. Maitiro aya anogona kubvisa nitrogen pamusoro pecarbon powder nesilicon powder.
2) Maitiro ekubvisa nitrogen mukupisa kwakanyanya, kubvisa oxygen kusvika pa5×10-4 Pa, wozodziisa kusvika pa950 ℃, wozoisa hydrogen, zvichiita kuti pressure yemukamuri isvike pa80 kPa, ichiramba ichishandiswa kwemaminitsi gumi nemashanu, uye ichidzokororwa kana. Maitiro aya anogona kubvisa nitrogen pamusoro pecarbon powder nesilicon powder, uye oendesa nitrogen munzvimbo inopisa.
3) Kugadzira gadziriro yechikamu chekupisa kwakaderera, bvisa kusvika pa5×10-4 Pa, wozopisa kusvika pa1350℃, chengeta kwemaawa gumi nemaviri, wozoisa hydrogen kuti pressure yemukamuri isvike pa80 kPa, chengeta kweawa imwe chete. Maitiro aya anogona kubvisa nitrogen yakaora panguva yekugadzira.
4) Kugadzirwa kwechikamu chekupisa kwakanyanya, zadza nechiyero chehuwandu hwegasi rehydrogen rakachena uye argon gas rakasanganiswa, ita kuti kumanikidzwa kwekamuri kusvike 80 kPa, kusimudzira tembiricha kusvika 2100℃, kuchengeta kwemaawa gumi. Maitiro aya anopedzisa kushandurwa kwesilicon carbide powder kubva ku β-SiC kuenda ku α-SiC uye anopedzisa kukura kwezvidimbu zvekristaro.
Pakupedzisira, mirira kuti tembiricha yemukamuri itonhore kusvika patembiricha yemukamuri, zadza kusvika padanho remhepo, wobva wabvisa hupfu.
3.2 Maitiro ekugadzira upfu mushure mekugadzira
Mushure mekunge upfu hwagadzirwa nenzira yataurwa pamusoro apa, hunofanira kugadziriswa mushure mekubvisa kabhoni, silicon nezvimwe tsvina yesimbi uye kuvharwa kwehukuru hwechinhu. Kutanga, upfu hwakagadzirwa hunoiswa mubhora kuti hupwanywe, uye upfu hwesilicon carbide hwakapwanywa hunoiswa muchoto chemuffle uye hunopiswa kusvika 450°C neokisijeni. Kabhoni yakasununguka iri muupfu inopiswa nekupisa kuti ibudise gasi recarbon dioxide rinobuda mukamuri, nokudaro zvichiita kuti kabhoni yakasununguka ibviswe. Mushure mezvo, mvura yekuchenesa ine acidic inogadzirwa uye inoiswa mumuchina wekuchenesa silicon carbide particle kuti icheneswe kubvisa kabhoni, silicon uye tsvina yesimbi yakasara inogadzirwa panguva yekugadzira. Mushure meizvozvo, acid yakasara inogezwa mumvura yakachena uye yoomeswa. Upfu hwakaomeswa hunovharwa muchidzitiro chinodedera kuti husarudzwe saizi yechinhu kuti kristaro ikure.
Nguva yekutumira: Nyamavhuvhu-08-2024