2. Epitaxial woonda filimu kukula
Gawoli limapereka gawo lothandizira lakuthupi kapena gawo loyendetsa pazida zamagetsi za Ga2O3. Chotsatira chofunika kwambiri ndi chigawo cha channel kapena epitaxial layer chomwe chimagwiritsidwa ntchito polimbana ndi magetsi ndi zonyamula katundu. Kuti muwonjezere mphamvu yowononga ndikuchepetsa kukana kwa conduction, makulidwe osinthika ndi ndende ya doping, komanso mtundu wabwino kwambiri wazinthu, ndizofunikira zina. Magulu apamwamba a Ga2O3 epitaxial amayikidwa pogwiritsa ntchito molecular beam epitaxy (MBE), metal organic chemical vapor deposition (MOCVD), halide vapor deposition (HVPE), pulsed laser deposition (PLD), ndi njira zoyikamo za CVD.
Table 2 Matekinoloje ena oyimira epitaxial
2.1 MBE njira
Ukadaulo wa MBE ndiwodziwikiratu chifukwa chakutha kukulitsa makanema apamwamba kwambiri, opanda chilema a β-Ga2O3 okhala ndi doping yowongolera yamtundu wa n chifukwa cha chilengedwe chake cha vacuum chokwera kwambiri komanso kuyera kwazinthu zambiri. Zotsatira zake, yakhala imodzi mwaukadaulo wophunziridwa kwambiri komanso wogulitsidwa wa β-Ga2O3 wowonda woyika mafilimu. Kuphatikiza apo, njira ya MBE idakonzekeranso bwino mawonekedwe apamwamba, otsika doped heterostructure β-(AlXGa1-X)2O3/Ga2O3 wosanjikiza filimu woonda. MBE imatha kuyang'anira mawonekedwe a pamwamba ndi ma morphology munthawi yeniyeni ndikulondola kosanjikiza kwa atomiki pogwiritsa ntchito chiwonetsero champhamvu cha ma elekitironi diffraction (RHEED). Komabe, mafilimu a β-Ga2O3 omwe amakula pogwiritsa ntchito teknoloji ya MBE amakumanabe ndi zovuta zambiri, monga kuchepa kwa kukula ndi kukula kwa kanema kakang'ono. Kafukufukuyu anapeza kuti kukula kwake kunali mu dongosolo la (010)> (001)> (-201)> (100). Pansi pazikhalidwe za Ga-rich pang'ono za 650 mpaka 750 ° C, β-Ga2O3 (010) imawonetsa kukula bwino ndi malo osalala komanso kukula kwakukulu. Pogwiritsa ntchito njirayi, β-Ga2O3 epitaxy inapindula bwino ndi RMS roughness ya 0.1 nm. β-Ga2O3 M'malo olemera a Ga, mafilimu a MBE omwe amakula pa kutentha kosiyana akuwonetsedwa pachithunzichi. Novel Crystal Technology Inc. yapanga bwino epitaxially 10 × 15mm2 β-Ga2O3MBE zowotcha. Amapereka magawo apamwamba kwambiri (010) opangidwa ndi β-Ga2O3 single crystal substrates okhala ndi makulidwe a 500 μm ndi XRD FWHM pansi pa masekondi 150 arc. Gawo lapansi ndi Sn doped kapena Fe doped. Sn-doped conductive substrate ili ndi doping concentration ya 1E18 mpaka 9E18cm−3, pomwe yachitsulo-doped theka-insulating gawo lapansi imakhala ndi resistivity yoposa 10E10 Ω cm.
2.2 MOCVD njira
MOCVD imagwiritsa ntchito zitsulo zopangidwa ndi zitsulo monga zinthu zoyambira kukulitsa mafilimu opyapyala, potero kukwaniritsa malonda akuluakulu. Mukamakula Ga2O3 pogwiritsa ntchito njira ya MOCVD, trimethylgallium (TMGa), triethylgallium (TEGa) ndi Ga (dipentyl glycol formate) amagwiritsidwa ntchito ngati gwero la Ga, pamene H2O, O2 kapena N2O amagwiritsidwa ntchito ngati gwero la mpweya. Kukula pogwiritsa ntchito njirayi kumafuna kutentha kwambiri (>800 ° C). Ukadaulo uwu uli ndi kuthekera kokwaniritsa mayendedwe otsika onyamulira komanso kutentha kwambiri komanso kutsika kwa electron kuyenda, kotero ndikofunikira kwambiri pakukwaniritsidwa kwa zida zamphamvu za β-Ga2O3 zogwira ntchito kwambiri. Poyerekeza ndi njira ya kukula kwa MBE, MOCVD ili ndi ubwino wopeza kukula kwakukulu kwa mafilimu a β-Ga2O3 chifukwa cha maonekedwe a kutentha kwapamwamba komanso kusintha kwa mankhwala.
Chithunzi 7 β-Ga2O3 (010) AFM chithunzi
Chithunzi 8 β-Ga2O3 Ubale pakati paμndi kukana kwa pepala kuyeza ndi Hall ndi kutentha
2.3 Njira ya HVPE
HVPE ndiukadaulo wokhwima wa epitaxial ndipo wagwiritsidwa ntchito kwambiri pakukula kwa epitaxial kwa III-V kompositi semiconductors. HVPE imadziwika ndi mtengo wake wotsika wopanga, kukula mwachangu, komanso makulidwe apamwamba amafilimu. Tiyenera kudziwa kuti HVPEβ-Ga2O3 nthawi zambiri imawonetsa morphology yapamtunda komanso kuchulukana kwakukulu kwa zolakwika zapamtunda ndi maenje. Choncho, njira zamakina ndi makina opukuta zimafunika musanapange chipangizocho. Ukadaulo wa HVPE wa β-Ga2O3 epitaxy nthawi zambiri umagwiritsa ntchito gaseous GaCl ndi O2 ngati zotsogola kuti zilimbikitse kutentha kwambiri kwa (001) β-Ga2O3 matrix. Chithunzi 9 chikuwonetsa mawonekedwe a pamwamba ndi kukula kwa filimu ya epitaxial monga ntchito ya kutentha. M'zaka zaposachedwa, Novel Crystal Technology Inc. yaku Japan yachita bwino kwambiri pazamalonda mu HVPE homoepitaxial β-Ga2O3, yokhala ndi makulidwe a epitaxial a 5 mpaka 10 μm ndi makulidwe opindika a 2 ndi 4 mainchesi. Kuphatikiza apo, 20 μm wandiweyani wa HVPE β-Ga2O3 homoepitaxial wafers opangidwa ndi China Electronics Technology Group Corporation nawonso alowa gawo lazamalonda.
Chithunzi 9 njira ya HVPE β-Ga2O3
2.4 PLD njira
Ukadaulo wa PLD umagwiritsidwa ntchito makamaka kuyika mafilimu ovuta a oxide ndi ma heterostructures. Panthawi ya kukula kwa PLD, mphamvu ya photon imaphatikizidwa ndi zinthu zomwe mukufuna kudzera mu njira yotulutsa ma elekitironi. Mosiyana ndi MBE, magwero a PLD amapangidwa ndi kuwala kwa laser komwe kumakhala ndi mphamvu zambiri (> 100 eV) ndipo kenako kumayikidwa pagawo lotentha. Komabe, panthawi ya ablation, tinthu tating'onoting'ono tambiri timene timatulutsa timadzi tating'onoting'ono tating'onoting'ono tating'onoting'ono tating'onoting'ono tating'onoting'ono tating'onoting'ono tating'ono tating'onoting'ono tating'onoting'ono tating'onoting'ono tating'onoting'ono ta filimuyo. Mofanana ndi njira ya MBE, RHEED ingagwiritsidwe ntchito kuyang'anira mawonekedwe a pamwamba ndi morphology ya zinthu mu nthawi yeniyeni pa PLD β-Ga2O3 ndondomeko yowonongeka, kulola ofufuza kuti apeze molondola chidziwitso cha kukula. Njira ya PLD ikuyembekezeka kukula kwambiri mafilimu a β-Ga2O3, ndikupangitsa kuti ikhale njira yabwino yolumikizirana ndi ohmic mu zida zamagetsi za Ga2O3.
Chithunzi 10 AFM chithunzi cha Si doped Ga2O3
2.5 Njira ya MIST-CVD
MIST-CVD ndiukadaulo wosavuta komanso wotsika mtengo wokulitsa makanema. Njira ya CVD iyi imaphatikizapo zomwe zimachitika popopera kalambulabwalo wa atomized pagawo laling'ono kuti mukwaniritse filimu yopyapyala. Komabe, mpaka pano, Ga2O3 yokulirapo pogwiritsa ntchito nkhungu CVD ikadalibe zinthu zabwino zamagetsi, zomwe zimasiya malo ambiri oti zitheke komanso kukhathamiritsa mtsogolo.
Nthawi yotumiza: May-30-2024