Pakadali pano, makampani a SiC akusintha kuchoka pa 150 mm (mainchesi 6) kufika pa 200 mm (mainchesi 8). Pofuna kukwaniritsa kufunika kwachangu kwa ma wafer akuluakulu komanso apamwamba a SiC homoepitaxial mumakampaniwa, 150mm ndi 200mm.Ma wafer a 4H-SiC homoepitaxialZakonzedwa bwino pazipinda zapakhomo pogwiritsa ntchito zida zokulira za 200mm SiC epitaxial zomwe zapangidwa paokha. Njira yokulira ya homoepitaxial yoyenera 150mm ndi 200mm idapangidwa, momwe kuchuluka kwa kukula kwa epitaxial kumatha kupitirira 60um/h. Ngakhale zikukwaniritsa epitaxy yothamanga kwambiri, mtundu wa epitaxial wafer ndi wabwino kwambiri. Kufanana kwa makulidwe a 150 mm ndi 200 mmMa wafer a SiC epitaxialikhoza kulamulidwa mkati mwa 1.5%, kufanana kwa kuchuluka kwake ndi kochepera 3%, kuchuluka kwa chilema choopsa ndi kochepera 0.3 particles/cm2, ndipo epitaxial surface roughness root mean square Ra ndi yochepera 0.15nm, ndipo zizindikiro zonse zapakati pa ndondomeko zili pamlingo wapamwamba wamakampani.
Silikoni Carbide (SiC)ndi imodzi mwa zinthu zoimira zipangizo zamagetsi za m'badwo wachitatu. Ili ndi mphamvu yamagetsi yotsika kwambiri, kutentha kwabwino kwambiri, liwiro lalikulu la ma elekitironi, komanso kukana kwamphamvu kwa ma radiation. Yakulitsa kwambiri mphamvu yogwiritsira ntchito mphamvu zamagetsi ndipo imatha kukwaniritsa zofunikira za ntchito za zipangizo zamagetsi zamagetsi za m'badwo wotsatira zamphamvu kwambiri, zazikulu, kutentha kwambiri, ma radiation ambiri ndi zina zoopsa. Ikhoza kuchepetsa malo, kuchepetsa kugwiritsa ntchito mphamvu ndikuchepetsa zofunikira zoziziritsira. Yabweretsa kusintha kwakukulu kwa magalimoto atsopano amagetsi, mayendedwe a sitima, ma gridi anzeru ndi madera ena. Chifukwa chake, ma semiconductor a silicon carbide azindikirika ngati zinthu zabwino kwambiri zomwe zidzatsogolere m'badwo wotsatira wa zida zamagetsi zamagetsi zamphamvu kwambiri. M'zaka zaposachedwa, chifukwa cha chithandizo cha dziko lonse cha chitukuko cha makampani opanga ma semiconductor a m'badwo wachitatu, kafukufuku ndi chitukuko ndi kumanga makina a makampani a zida za 150 mm SiC atsirizidwa ku China, ndipo chitetezo cha unyolo wamafakitale chatsimikizika. Chifukwa chake, cholinga cha makampaniwa chasintha pang'onopang'ono kukhala kuwongolera ndalama ndikuwongolera magwiridwe antchito. Monga momwe zasonyezedwera mu Table 1, poyerekeza ndi 150 mm, 200 mm SiC ili ndi chiŵerengero chachikulu cha kugwiritsa ntchito m'mphepete, ndipo kutulutsa kwa single wafer chips kumatha kuwonjezeka ndi pafupifupi nthawi 1.8. Pambuyo poti ukadaulo wakula, mtengo wopanga wa single chip ukhoza kuchepetsedwa ndi 30%. Kupita patsogolo kwa ukadaulo wa 200 mm ndi njira yolunjika "yochepetsera ndalama ndikuwonjezera magwiridwe antchito", ndipo ndichinthu chofunikira kwambiri kuti makampani opanga ma semiconductor mdziko langa "ayende limodzi" kapena "kutsogolera".
Mosiyana ndi njira ya chipangizo cha Si,Zipangizo zamagetsi za SiC semiconductorZonse zimakonzedwa ndikukonzedwa ndi zigawo za epitaxial ngati mwala wapangodya. Ma wafer a Epitaxial ndi zinthu zofunika kwambiri pazida zamagetsi za SiC. Ubwino wa gawo la epitaxial umatsimikiza mwachindunji phindu la chipangizocho, ndipo mtengo wake umawerengera 20% ya mtengo wopanga ma chip. Chifukwa chake, kukula kwa epitaxial ndi ulalo wofunikira kwambiri pakati pazida zamagetsi za SiC. Malire apamwamba a mulingo wa epitaxial amatsimikiziridwa ndi zida za epitaxial. Pakadali pano, mulingo wa malo a zida za epitaxial za 150mm SiC ku China ndi wokwera kwambiri, koma kapangidwe kake konse ka 200mm kakutsalira kumbuyo kwa mulingo wapadziko lonse lapansi nthawi yomweyo. Chifukwa chake, kuti athetse zosowa zachangu komanso mavuto oletsa kupanga zinthu zazikulu komanso zapamwamba za epitaxial kuti apange makampani opanga ma semiconductor am'badwo wachitatu, pepalali likuwonetsa zida za epitaxial za 200 mm SiC zomwe zapangidwa bwino mdziko langa, ndikufufuza njira ya epitaxial. Mwa kukonza bwino magawo a ndondomeko monga kutentha kwa ndondomeko, kuchuluka kwa mpweya wonyamula, chiŵerengero cha C/Si, ndi zina zotero, kufanana kwa kuchuluka kwa <3%, makulidwe osafanana <1.5%, roughness Ra <0.2 nm ndi kufa kwa defect defect defect <0.3 grains/cm2 ya 150 mm ndi 200 mm SiC epitaxial wafers yokhala ndi 200 mm silicon carbide epitaxial furnace yopangidwa yokha imapezedwa. Mlingo wa njira ya zida ukhoza kukwaniritsa zosowa za SiC power device yokonzedwa bwino kwambiri.
Kuyesera 1
1.1 Mfundo yaSiC epitaxialnjira
Njira yokulira ya 4H-SiC homoepitaxial imaphatikizapo magawo awiri ofunikira, omwe ndi, kupukuta kwapamwamba kwambiri kwa substrate ya 4H-SiC ndi njira yofanana yoyika nthunzi ya mankhwala. Cholinga chachikulu cha kupukuta kwa substrate ndikuchotsa kuwonongeka kwa substrate pambuyo popukuta wafer, madzi otsala opukuta, tinthu tating'onoting'ono ndi oxide, ndipo kapangidwe ka atomu kokhazikika kangapangidwe pamwamba pa substrate popukuta. Kupukuta kwa in-situ nthawi zambiri kumachitika mumlengalenga wa hydrogen. Malinga ndi zofunikira zenizeni za ndondomekoyi, mpweya wochepa wothandiza ukhoza kuwonjezeredwa, monga hydrogen chloride, propane, ethylene kapena silane. Kutentha kwa kupukuta kwa in-situ hydrogen nthawi zambiri kumakhala pamwamba pa 1600 ℃, ndipo kuthamanga kwa chipinda chochitirapo kanthu nthawi zambiri kumayendetsedwa pansi pa 2×104 Pa panthawi yopukuta.
Pambuyo poti pamwamba pa substrate payatsidwa ndi etching ya in-situ, imalowa mu njira yoika nthunzi ya mankhwala otentha kwambiri, ndiko kuti, gwero la kukula (monga ethylene/propane, TCS/silane), gwero la doping (n-type doping source nitrogen, p-type doping source TAl), ndi mpweya wothandiza monga hydrogen chloride zimanyamulidwa kupita ku chipinda chochitira reaction kudzera mu mpweya wonyamula (nthawi zambiri hydrogen). Mpweya ukachita reaction mu chipinda chochitira reaction cha kutentha kwambiri, gawo la precursor limachita reaction ndi kuyamwa pamwamba pa wafer, ndipo gawo limodzi la 4H-SiC epitaxial lokhala ndi doping concentration yeniyeni, makulidwe enieni, ndi khalidwe lapamwamba limapangidwa pamwamba pa substrate pogwiritsa ntchito substrate ya single-crystal 4H-SiC ngati template. Pambuyo pa zaka zambiri zofufuza zaukadaulo, ukadaulo wa 4H-SiC homoepitaxial wakula kwambiri ndipo umagwiritsidwa ntchito kwambiri popanga mafakitale. Ukadaulo wa 4H-SiC homoepitaxial womwe umagwiritsidwa ntchito kwambiri padziko lonse lapansi uli ndi makhalidwe awiri wamba:
(1) Pogwiritsa ntchito njira yochotsera mpweya (yofanana ndi kristalo ya <0001>, yopita ku <11-20> njira yochotsera mpweya) ngati chitsanzo, gawo lopanda mpweya la kristalo la 4H-SiC epitaxial lopanda zonyansa limayikidwa pa gawolo mu mawonekedwe a njira yokulira ya step-flow. Kukula koyambirira kwa 4H-SiC homoepitaxial kunagwiritsa ntchito gawo lopanda mpweya la kristalo, ndiko kuti, <0001> Si plane kuti ikule. Kuchuluka kwa masitepe a atomiki pamwamba pa gawo lopanda mpweya la kristalo ndi kochepa ndipo malo otsetsereka ndi otakata. Kukula kwa nucleation ya magawo awiri ndikosavuta kuchitika panthawi ya epitaxy kuti apange 3C crystal SiC (3C-SiC). Mwa kudula kosakhazikika, masitepe a atomiki okhala ndi terrace yopapatiza amatha kuyambitsidwa pamwamba pa gawo la 4H-SiC <0001>, ndipo choyambira chokhazikikacho chimatha kufika pamalo a atomiki ndi mphamvu yochepa pamwamba kudzera mu kufalikira kwa pamwamba. Pa sitepe, malo olumikizirana a atomu/gulu la mamolekyulu ndi apadera, kotero mu njira yokulira ya kayendedwe ka mayendedwe, gawo la epitaxial likhoza kulandira bwino mndandanda wa Si-C wa ma atomu awiri ophatikizika wa gawo lapansi kuti lipange kristalo imodzi yokhala ndi gawo lofanana la kristalo ndi gawo lapansi.
(2) Kukula kwa epitaxial mwachangu kumachitika poyambitsa gwero la silicon lomwe lili ndi chlorine. Mu machitidwe odziwika bwino a SiC chemical vapor deposition, silane ndi propane (kapena ethylene) ndiye magwero akuluakulu okulira. Powonjezera kuchuluka kwa kukula mwa kuwonjezera kuchuluka kwa kukula kwa gwero, pamene kuthamanga kwa gawo la silicon kukupitirira kukula, ndikosavuta kupanga magulu a silicon pogwiritsa ntchito homogeneous gas phase nucleation, zomwe zimachepetsa kwambiri kuchuluka kwa kugwiritsa ntchito kwa gwero la silicon. Kupangidwa kwa magulu a silicon kumachepetsa kwambiri kukula kwa epitaxial growth rate. Nthawi yomweyo, magulu a silicon amatha kusokoneza kukula kwa step flow ndikuyambitsa defect nucleation. Pofuna kupewa homogeneous gas phase nucleation ndikuwonjezera kuchuluka kwa epitaxial growth rate, kuyambitsa magwero a silicon okhala ndi chlorine pakadali pano ndiyo njira yayikulu yowonjezera kuchuluka kwa epitaxial growth rate ya 4H-SiC.
Zipangizo za SiC epitaxial za 1.2 200 mm (8-inch) ndi momwe zimagwirira ntchito
Mayeso omwe afotokozedwa mu pepalali adachitika pa chipangizo cha SiC epitaxial chogwirizana ndi 150/200 mm (6/8-inch) chopangidwa paokha ndi 48th Institute of China Electronics Technology Group Corporation. Ng'anjo ya epitaxial imathandizira kukweza ndi kutsitsa kwa wafer yokha. Chithunzi 1 ndi chithunzi cha kapangidwe ka mkati mwa chipinda chochitirapo kanthu cha chipangizo cha epitaxial. Monga momwe zasonyezedwera mu Chithunzi 1, khoma lakunja la chipinda chochitirapo kanthu ndi belu la quartz lokhala ndi interlayer yozizira ndi madzi, ndipo mkati mwa belu muli chipinda chochitirapo kanthu chotentha kwambiri, chomwe chimapangidwa ndi carbon felt yotenthetsera kutentha, graphite yapadera yoyera kwambiri, maziko ozungulira a graphite, ndi zina zotero. Belu lonse la quartz lili ndi cylindrical induction coil, ndipo chipinda chochitirapo kanthu mkati mwa belu chimatenthedwa ndi electromagnetically ndi magetsi olowera apakatikati. Monga momwe zasonyezedwera pa Chithunzi 1 (b), mpweya wonyamula, mpweya wochitapo kanthu, ndi mpweya wogwiritsa ntchito mankhwala osokoneza bongo zonse zimadutsa pamwamba pa wafer mumtsinje wopingasa wa laminar kuchokera pamwamba pa chipinda chochitirapo kanthu kupita pansi pa chipinda chochitirapo kanthu ndipo zimatulutsidwa kuchokera kumapeto kwa mpweya wakumbuyo. Kuti zitsimikizire kuti mkati mwa wafer muli bwino, wafer wonyamulidwa ndi mpweya woyandama umazunguliridwa nthawi zonse panthawiyi.
Gawo lomwe lagwiritsidwa ntchito mu kuyeseraku ndi gawo la 150 mm, 200 mm (mainchesi 6, mainchesi 8) <1120> loyang'anira 4°off-angle conductive n-type 4H-SiC double-sided polished SiC substrate lopangidwa ndi Shanxi Shuoke Crystal. Trichlorosilane (SiHCl3, TCS) ndi ethylene (C2H4) zimagwiritsidwa ntchito ngati magwero akuluakulu okulira mu kuyesera kwa process, pakati pawo TCS ndi C2H4 zimagwiritsidwa ntchito ngati silicon source ndi carbon source motsatana, high-purity nitrogen (N2) imagwiritsidwa ntchito ngati n-type doping source, ndipo hydrogen (H2) imagwiritsidwa ntchito ngati dilution gas ndi carrier gas. Kutentha kwa epitaxial process ndi 1600 ~1660 ℃, process pressure ndi 8×103 ~12×103 Pa, ndipo H2 carrier gas flow rate ndi 100~140 L/min.
1.3 Kuyesa ndi kufotokozera za Epitaxial wafer
Fourier infrared spectrometer (wopanga zida Thermalfisher, chitsanzo iS50) ndi mercury probe concentration tester (wopanga zida Semilab, chitsanzo 530L) zinagwiritsidwa ntchito kufotokoza avereji ndi kufalikira kwa epitaxial layer thickness ndi doping concentration; makulidwe ndi doping concentration ya mfundo iliyonse mu epitaxial layer zinadziwika potenga mfundo motsatira mzere wa diameter womwe umadutsa mzere wabwinobwino wa main reference edge pa 45° pakati pa wafer ndi kuchotsa m'mphepete mwa 5 mm. Pa wafer wa 150 mm, mfundo 9 zinatengedwa motsatira mzere umodzi wa diameter (ma diameter awiri anali olunjika kwa wina ndi mnzake), ndipo pa wafer wa 200 mm, mfundo 21 zinatengedwa, monga momwe zasonyezedwera pa Chithunzi 2. Maikulosikopu ya atomiki force (wopanga zida Bruker, chitsanzo Dimension Icon) inagwiritsidwa ntchito kusankha madera a 30 μm×30 μm pakati ndi m'mphepete (kuchotsa m'mphepete mwa 5 mm) a epitaxial wafer kuti ayesere kuuma kwa pamwamba pa epitaxial layer; Zolakwika za epitaxial layer zinayesedwa pogwiritsa ntchito choyezera zofooka za pamwamba (wopanga zida China Electronics Chithunzi cha 3D chinali ndi sensa ya radar (model Mars 4410 pro) yochokera ku Kefenghua.
Nthawi yotumizira: Sep-04-2024