3. Ukukhula kwefilimu emincane ye-Epitaxial
I-substrate inikeza isendlalelo sokwesekwa ngokomzimba noma isendlalelo sokuqondisa samadivayisi wamandla we-Ga2O3. Isendlalelo esilandelayo esibalulekile isendlalelo sesiteshi noma isendlalelo se-epitaxial esisetshenziselwa ukumelana nogesi kanye nokuthuthwa kwenkampani yenethiwekhi. Ukuze kwandiswe i-voltage ephukile futhi kuncishiswe ukumelana ne-conduction, ukushuba okulawulekayo nokugxila kwe-doping, kanye nekhwalithi ephezulu yezinto ezibonakalayo, ezinye izimfuneko. Izendlalelo ze-epitaxial zekhwalithi ephezulu ze-Ga2O3 zivame ukufakwa kusetshenziswa i-molecular beam epitaxy (MBE), i-metal organic chemical vapor deposition (MOCVD), i-halide vapor deposition (HVPE), i-pulsed laser deposition (PLD), kanye namasu okufakwa kwenkungu e-CVD.
Ithebula 2 Obunye ubuchwepheshe be-epitaxial obumele
3.1 MBE indlela
Ubuchwepheshe be-MBE baziwa ngekhono labo lokukhulisa amafilimu e-β-Ga2O3 ekhwalithi ephezulu, angenasici anedoping elawulekayo yohlobo lwe-n ngenxa yemvelo yayo yokungena ephezulu kanye nokuhlanzeka okuphezulu kwempahla. Ngenxa yalokho, isibe obunye bobuchwepheshe bokufakwa kwefilimu ezacile ye-β-Ga2O3 efundwa kakhulu futhi engase ihwebe. Ukwengeza, indlela ye-MBE iphinde yalungiselela ngempumelelo ungqimba lwefilimu oluncane lwekhwalithi ephezulu, olune-doped ephansi β-(AlXGa1-X)2O3/Ga2O3. I-MBE ingaqapha ukwakheka kwendawo kanye ne-morphology ngesikhathi sangempela ngokunemba kongqimba lwe-athomu ngokusebenzisa i-reflection high energy electron diffraction (RHEED). Nokho, amafilimu e-β-Ga2O3 akhuliswe kusetshenziswa ubuchwepheshe be-MBE asabhekene nezinselelo eziningi, njengezinga eliphansi lokukhula nosayizi wefilimu encane. Ucwaningo luthole ukuthi izinga lokukhula liku-(010)>(001)>(−201)>(100). Ngaphansi kwezimo ze-Ga-rich kancane ze-650 kuya ku-750 ° C, i-β-Ga2O3 (010) ibonisa ukukhula okuhle ngokubukeka okubushelelezi kanye nezinga eliphezulu lokukhula. Kusetshenziswa le ndlela, i-β-Ga2O3 epitaxy ifinyelelwe ngempumelelo nge-RMS enobushelelezi engu-0.1 nm. I-β-Ga2O3 Endaweni ecebile e-Ga, amafilimu e-MBE akhule emazingeni okushisa ahlukene ayaboniswa esithombeni. I-Novel Crystal Technology Inc. ikhiqize ngempumelelo ama-wafer angu-10 × 15mm2 β-Ga2O3MBE ngempumelelo. Ahlinzeka ngekhwalithi ephezulu (010) egxile ku-β-Ga2O3 eyodwa yekristalu substrates enogqinsi lwama-500 μm kanye ne-XRD FWHM ngaphansi kwamasekhondi angu-150 arc. I-substrate i-Sn doped noma i-Fe doped. I-Sn-doped conductive substrate ine-concentration ye-doping engu-1E18 kuya ku-9E18cm−3, kuyilapho i-iron-doped semi-insulating substrate ine-resistivity ephakeme kuno-10E10 Ω cm.
3.2 Indlela ye-MOCVD
I-MOCVD isebenzisa izinhlanganisela zezinto eziphilayo zensimbi njengezinto ezandulelayo ukuze kukhule amafilimu amancane, ngaleyo ndlela kuzuzwe ukukhiqizwa kwezentengiselwano okukhulu. Lapho ukhula i-Ga2O3 kusetshenziswa indlela ye-MOCVD, i-trimethylgallium (TMGa), i-triethylgallium (TEGa) ne-Ga (i-dipentyl glycol formate) ivame ukusetshenziswa njengomthombo we-Ga, kuyilapho i-H2O, i-O2 noma i-N2O isetshenziswa njengomthombo we-oxygen. Ukukhula usebenzisa le ndlela ngokuvamile kudinga izinga lokushisa eliphezulu (>800°C). Lobu buchwepheshe bunamandla okuzuza ukugxiliswa kwenkampani yenethiwekhi ephansi kanye nokuhamba kwe-electron ephakeme nezinga lokushisa eliphansi, ngakho-ke kubaluleke kakhulu ekugcwalisekeni kwamadivayisi wamandla we-β-Ga2O3 asebenza kakhulu. Uma kuqhathaniswa nendlela yokukhula ye-MBE, i-MOCVD inenzuzo yokufinyelela amazinga okukhula aphezulu kakhulu amafilimu e-β-Ga2O3 ngenxa yezimpawu zokukhula kwezinga lokushisa eliphezulu kanye nokusabela kwamakhemikhali.
Umfanekiso 7 β-Ga2O3 (010) AFM isithombe
Umfanekiso 8 β-Ga2O3 Ubudlelwano phakathiμnokumelana kweshidi kukalwa ngeHholo nezinga lokushisa
3.3 Indlela ye-HVPE
I-HVPE iwubuchwepheshe be-epitaxial obuvuthiwe futhi isetshenziswe kabanzi ekukhuleni kwe-epitaxial yama-semiconductors ayinhlanganisela ye-III-V. I-HVPE yaziwa ngezindleko zayo eziphansi zokukhiqiza, izinga lokukhula ngokushesha, nokushuba okuphezulu kwefilimu. Kufanele kuqashelwe ukuthi i-HVPEβ-Ga2O3 imvamisa ikhombisa i-morphology yamaholo kanye nokuminyana okuphezulu kokukhubazeka kwezindawo nemigodi. Ngakho-ke, izinqubo zokupholisha ngamakhemikhali nemishini ziyadingeka ngaphambi kokukhiqiza idivayisi. Ubuchwepheshe be-HVPE be-β-Ga2O3 epitaxy ngokuvamile busebenzisa i-Gaseous GaCl ne-O2 njengezandulela ukukhuthaza ukusabela kwezinga lokushisa eliphezulu kwe-(001) β-Ga2O3 matrix. Umfanekiso we-9 ubonisa isimo esiphezulu kanye nezinga lokukhula kwefilimu ye-epitaxial njengomsebenzi wokushisa. Eminyakeni yakamuva, i-Novel Crystal Technology Inc. yase-Japan izuze impumelelo ebalulekile yezentengiselwano ku-HVPE homoepitaxial β-Ga2O3, enogqinsi lwe-epitaxial layer engu-5 ukuya ku-10 μm nosayizi wama-wafer angama-intshi angu-2 no-4. Ngaphezu kwalokho, ama-wafer angu-20 μm awugqinsi we-HVPE β-Ga2O3 homoepitaxial akhiqizwa yi-China Electronics Technology Group Corporation nawo angenile esigabeni sokuthengisa.
Umfanekiso 9 indlela ye-HVPE β-Ga2O3
3.4 Indlela ye-PLD
Ubuchwepheshe be-PLD busetshenziselwa kakhulu ukufaka amafilimu e-oxide ayinkimbinkimbi nama-heterostructures. Ngesikhathi senqubo yokukhula ye-PLD, amandla e-photon ahlanganiswe nezinto eziqondiwe ngenqubo yokukhipha ama-electron. Ngokuphambene ne-MBE, izinhlayiya zomthombo we-PLD zakhiwa imisebe ye-laser enamandla amakhulu kakhulu (>100 eV) bese ifakwa endaweni engaphansi eshisayo. Kodwa-ke, phakathi nenqubo yokukhishwa kwe-ablation, ezinye izinhlayiya eziphezulu zamandla zizothinta ngokuqondile indawo yezinto ezibonakalayo, zidale amaphutha amaphuzu futhi ngaleyo ndlela zinciphise ikhwalithi yefilimu. Ngokufanayo nendlela ye-MBE, i-RHEED ingasetshenziswa ukuqapha ukwakheka kwendawo kanye ne-morphology yezinto ngesikhathi sangempela phakathi nenqubo yokubeka ye-PLD β-Ga2O3, okuvumela abacwaningi ukuthi bathole ngokunembile ulwazi lokukhula. Indlela ye-PLD kulindeleke ukuthi ikhule amafilimu e-β-Ga2O3 aqhuba kakhulu, iyenze ibe isisombululo sokuxhumana se-ohmic esithuthukisiwe kumadivayisi kagesi we-Ga2O3.
Umfanekiso 10 AFM isithombe sika-Si doped Ga2O3
3.5 Indlela ye-MIST-CVD
I-MIST-CVD ubuchwepheshe bokukhula kwefilimu elincanyana obulula futhi obungabizi kakhulu. Le ndlela ye-CVD ihilela ukusabela kokufafaza isandulela se-athomu ku-substrate ukuze kuzuzwe ukufakwa kwefilimu encane. Kodwa-ke, kuze kube manje, i-Ga2O3 ekhule kusetshenziswa i-CVD yenkungu isantula izakhiwo zikagesi ezinhle, okushiya indawo enkulu yokuthuthukiswa nokwenza kahle esikhathini esizayo.
Isikhathi sokuthumela: May-30-2024