Ukadaulo wofunikira pakukula kwaSiC epitaxialChoyamba, zipangizo ndi ukadaulo wowongolera zolakwika, makamaka paukadaulo wowongolera zolakwika womwe ungathe kulephera kugwiritsa ntchito chipangizo kapena kuwonongeka kodalirika. Kuphunzira momwe zinthu zilili ndi zolakwika zomwe zimafalikira mu gawo la epitaxial panthawi ya kukula kwa epitaxial, malamulo osamutsa ndi kusintha kwa zolakwika zomwe zili pakati pa gawo la substrate ndi gawo la epitaxial, komanso njira yopangira zolakwika zomwe zili ndi nucleation ndiye maziko ofotokozera bwino mgwirizano pakati pa zolakwika za substrate ndi zolakwika za kapangidwe ka epitaxial, zomwe zingathandize kuwongolera bwino mawonekedwe a substrate ndi kukonza njira ya epitaxial.
Zolakwika zazigawo za epitaxial za silicon carbideZigawo ziwiri zimagawidwa m'magulu awiri: zolakwika za kristalo ndi zolakwika za mawonekedwe a pamwamba. Zolakwika za kristalo, kuphatikizapo zolakwika za mfundo, kusokonekera kwa screw, zolakwika za microtubule, kusokonekera kwa m'mphepete, ndi zina zotero, makamaka zimachokera ku zolakwika pa ma substrates a SiC ndikufalikira mu epitaxial layer. Zolakwika za mawonekedwe a pamwamba zimatha kuwonedwa mwachindunji ndi maso osawoneka bwino pogwiritsa ntchito maikulosikopu ndipo zimakhala ndi mawonekedwe wamba a mawonekedwe. Zolakwika za mawonekedwe a pamwamba zimaphatikizapo makamaka: Kukwapula, Kusokonekera kwa Triangular, Kusokonekera kwa Karoti, Kugwa, ndi Tinthu, monga momwe zasonyezedwera pa Chithunzi 4. Pa nthawi ya epitaxial, tinthu tachilendo, zolakwika za substrate, kuwonongeka kwa pamwamba, ndi kusokonekera kwa njira ya epitaxial zonse zitha kukhudza njira yokulira ya kayendedwe ka sitepe, zomwe zimapangitsa kuti zolakwika za mawonekedwe a pamwamba zikhale pamwamba.
Gome 1. Zomwe zimayambitsa kupangika kwa zolakwika za matrix wamba ndi zolakwika za mawonekedwe a pamwamba mu zigawo za SiC epitaxial
Zolakwika za mfundo
Zolakwika za mfundo zimapangidwa ndi malo opanda kanthu kapena mipata pamalo amodzi kapena malo angapo a lattice, ndipo alibe malo owonjezera. Zolakwika za mfundo zitha kuchitika nthawi iliyonse yopanga, makamaka pakuyika ma ion. Komabe, zimakhala zovuta kuzizindikira, ndipo ubale pakati pa kusintha kwa zolakwika za mfundo ndi zolakwika zina ndi wovuta kwambiri.
Ma Micropipe (MP)
Ma micropipe ndi ma hollow screw dislocations omwe amafalikira motsatira mzere wa kukula, ndi Burgers vector <0001>. Kukula kwa ma microtubes kumayambira pa gawo la micron mpaka ma micron makumi ambiri. Ma microtubes amasonyeza mawonekedwe akuluakulu ofanana ndi dzenje pamwamba pa ma SiC wafers. Kawirikawiri, kuchuluka kwa ma microtubes ndi pafupifupi 0.1 ~ 1cm-2 ndipo kumapitirira kuchepa pakuwunika khalidwe la ma wafer amalonda.
Kusokonekera kwa screw (TSD) ndi kusokonekera kwa m'mphepete (TED)
Kusokonekera kwa SiC ndiye gwero lalikulu la kuwonongeka ndi kulephera kwa chipangizo. Kusokonekera kwa screw (TSD) ndi kusokonekera kwa edge (TED) zonse zimayenda motsatira mzere wa kukula, ndi ma Burgers vectors a <0001> ndi 1/3<11–20>, motsatana.
Kusuntha kwa screw (TSD) ndi kusuntha kwa m'mphepete (TED) kumatha kuchoka pa substrate kupita pamwamba pa wafer ndikubweretsa mawonekedwe ang'onoang'ono ofanana ndi dzenje (Chithunzi 4b). Kawirikawiri, kuchuluka kwa kusuntha kwa m'mphepete kumakhala pafupifupi nthawi 10 kuposa kusuntha kwa screw. Kusuntha kwa screw kotalikirapo, komwe kumachokera pa substrate kupita ku epilayer, kumathanso kusintha kukhala zolakwika zina ndikufalikira motsatira mzere wokulira.SiC epitaxialkukula, kusokonekera kwa screw kumasanduka zolakwika zomangira (SF) kapena zolakwika za karoti, pomwe kusokonekera kwa m'mphepete mwa epilayers kumawonetsedwa kuti kwasinthidwa kuchokera ku kusokonekera kwa basal plane (BPDs) komwe kumatengera gawo lapansi panthawi ya kukula kwa epitaxial.
Kusokonezeka kwa ndege yoyambira (BPD)
Ili pa SiC basal plane, yokhala ndi Burgers vector ya 1/3 <11–20>. Ma BPD samapezeka kawirikawiri pamwamba pa ma SiC wafers. Nthawi zambiri amakhala pamwamba pa substrate yokhala ndi kuchuluka kwa 1500 cm-2, pomwe kuchuluka kwawo mu epilayer ndi pafupifupi 10 cm-2. Kuzindikira ma BPD pogwiritsa ntchito photoluminescence (PL) kukuwonetsa mawonekedwe olunjika, monga momwe zasonyezedwera pa Chithunzi 4c.SiC epitaxialkukula, ma BPD otalikirapo angasandulike kukhala ma stacking faults (SF) kapena edge dislocations (TED).
Zolakwika zoyika zinthu m'mabokosi (SFs)
Zolakwika mu dongosolo la stacking la SiC basal plane. Zolakwika za stacking zitha kuwonekera mu epitaxial layer mwa kulandira ma SF mu substrate, kapena kukhala zokhudzana ndi kufalikira ndi kusintha kwa basal plane dislocations (BPDs) ndi threading screw dislocations (TSDs). Kawirikawiri, kuchuluka kwa ma SF ndi kochepera 1 cm-2, ndipo amawonetsa mawonekedwe a triangular akapezeka pogwiritsa ntchito PL, monga momwe zasonyezedwera pa Chithunzi 4e. Komabe, mitundu yosiyanasiyana ya zolakwika za stacking ingapangidwe mu SiC, monga mtundu wa Shockley ndi mtundu wa Frank, chifukwa ngakhale pang'ono kusokonezeka kwa mphamvu ya stacking pakati pa ndege kungayambitse kusakhazikika kwakukulu mu dongosolo la stacking.
Kugwa
Vuto la kugwa limachokera makamaka kutsika kwa tinthu tating'onoting'ono pamwamba ndi m'mbali mwa chipinda chochitira zinthu panthawi ya kukula, zomwe zingakonzedwe bwino mwa kukonza bwino nthawi ndi nthawi zinthu zogwiritsidwa ntchito pa graphite ya chipinda chochitira zinthu.
Chilema cha triangular
Ndi kuphatikiza kwa 3C-SiC polytype komwe kumafikira pamwamba pa SiC epilayer motsatira njira ya basal plane, monga momwe zasonyezedwera pa Chithunzi 4g. Kungapangidwe ndi tinthu tomwe timagwa pamwamba pa SiC epilayer panthawi ya kukula kwa epitaxial. Tinthu timeneti timalowa mu epilayer ndipo timasokoneza njira yokulira, zomwe zimapangitsa kuti 3C-SiC polytype inclusions, zomwe zimawonetsa mawonekedwe a pamwamba pa triangular okhala ndi tinthu timeneti tomwe tili pamalo otsetsereka a dera la triangular. Kafukufuku wambiri wanenanso kuti chiyambi cha kuphatikiza kwa polytype ndi kukanda pamwamba, ma micropipes, ndi magawo osayenera a njira yokulira.
Chilema cha karoti
Kaloti wofooka ndi gulu la zinthu zomwe zimakhala ndi malekezero awiri omwe ali pa TSD ndi SF basal crystal planes, zomwe zimathetsedwa ndi Frank-type dislocation, ndipo kukula kwa kaloti wofooka kumagwirizana ndi prismatic stacking fault. Kuphatikiza kwa zinthuzi kumapanga mawonekedwe a pamwamba pa kaloti wofooka, womwe umawoneka ngati mawonekedwe a kaloti wokhala ndi kachulukidwe kochepera 1 cm-2, monga momwe zasonyezedwera pa Chithunzi 4f. Kaloti wofooka amapangika mosavuta pakukanda, TSD, kapena zolakwika za substrate.
Kukanda
Kukwawa ndi kuwonongeka kwa makina pamwamba pa ma wafer a SiC omwe amapangidwa panthawi yopanga, monga momwe zasonyezedwera pa Chithunzi 4h. Kukwawa pa gawo la SiC kungasokoneze kukula kwa epilayer, kupanga mzere wa kusokonekera kwakukulu mkati mwa epilayer, kapena kukwawa kungakhale maziko a kupangika kwa zolakwika za karoti. Chifukwa chake, ndikofunikira kupukuta bwino ma wafer a SiC chifukwa kukwawa kumeneku kumatha kukhudza kwambiri magwiridwe antchito a chipangizocho akawonekera pamalo ogwirira ntchito a chipangizocho.
Zolakwika zina za mawonekedwe a pamwamba
Kupindika kwa Step ndi vuto la pamwamba lomwe limachitika panthawi ya kukula kwa SiC epitaxial, komwe kumapanga ma triangles obtuse kapena mawonekedwe a trapezoidal pamwamba pa SiC epilayer. Palinso zolakwika zina zambiri pamwamba, monga maenje a pamwamba, ma bumps ndi madontho. Zolakwika izi nthawi zambiri zimachitika chifukwa cha njira zosakula bwino komanso kuchotsa kwathunthu kuwonongeka kwa kupukuta, zomwe zimakhudza magwiridwe antchito a chipangizocho.
Nthawi yotumizira: Juni-05-2024