Ubuchwepheshe bokukhula kokusanhlamvu okumile okune-oxidized kanye ne-epitaxial-Ⅱ

2. Ukukhula kwefilimu encane ye-Epitaxial

I-substrate inikeza ungqimba lokusekela ngokomzimba noma ungqimba oluqhubayo lwamadivayisi kagesi e-Ga2O3. Ungqimba olulandelayo olubalulekile ungqimba lwesiteshi noma ungqimba lwe-epitaxial olusetshenziselwa ukumelana ne-voltage kanye nokuthuthwa kwenkampani. Ukuze kwandiswe i-voltage yokuqhekeka futhi kuncishiswe ukumelana ne-conduction, ukujiya okulawulwayo kanye nokuhlushwa kwe-doping, kanye nekhwalithi ephezulu yezinto ezibonakalayo, ezinye zezinto ezidingekayo. Izingqimba ze-epitaxial ze-Ga2O3 ezisezingeni eliphezulu zivame ukufakwa kusetshenziswa i-epitaxy ye-molecular beam (MBE), i-metal organic chemical vapor deposition (MOCVD), i-halide vapor deposition (HVPE), i-pulsed laser deposition (PLD), kanye namasu okubeka i-fog CVD.

Ithebula 2 Ezinye izindlela zobuchwepheshe ezimele i-epitaxial

2.1 Indlela ye-MBE

Ubuchwepheshe be-MBE budume ngekhono labo lokukhulisa amafilimu e-β-Ga2O3 asezingeni eliphezulu, angenamaphutha ane-doping yohlobo lwe-n elawulwayo ngenxa yendawo yayo yokuphuma kwe-vacuum ephezulu kakhulu kanye nobumsulwa bezinto ezibonakalayo obuphezulu. Ngenxa yalokho, bube ngolunye lobuchwepheshe bokufakwa kwefilimu encane ye-β-Ga2O3 efundwe kabanzi futhi engase ithengiswe. Ngaphezu kwalokho, indlela ye-MBE iphinde yalungiselela ngempumelelo ungqimba lwefilimu encane ye-β-(AlXGa1-X)2O3/Ga2O3 esezingeni eliphezulu, ephansi. I-MBE ingaqapha isakhiwo sobuso kanye nokwakheka kwaso ngesikhathi sangempela ngokunemba kwesendlalelo se-athomu ngokusebenzisa i-reflection high energy electron diffraction (RHEED). Kodwa-ke, amafilimu e-β-Ga2O3 akhuliswe kusetshenziswa ubuchwepheshe be-MBE asabhekene nezinselele eziningi, njengesilinganiso sokukhula esiphansi kanye nosayizi wefilimu encane. Ucwaningo luthole ukuthi izinga lokukhula lalilandelana ngo-(010)>(001)>(−201)>(100). Ngaphansi kwezimo ezicebile kancane ze-Ga ezingu-650 kuya ku-750°C, i-β-Ga2O3 (010) ikhombisa ukukhula okuhle kakhulu ngobuso obubushelelezi kanye nesilinganiso sokukhula esiphezulu. Kusetshenziswa le ndlela, i-β-Ga2O3 epitaxy itholakale ngempumelelo ngokuqina kwe-RMS okungu-0.1 nm. I-β-Ga2O3 Endaweni ecebile nge-Ga, amafilimu e-MBE akhuliswe emazingeni okushisa ahlukene aboniswe esithombeni. I-Novel Crystal Technology Inc. ikhiqize ngempumelelo ama-wafer angu-10 × 15mm2 β-Ga2O3MBE. Ahlinzeka ngama-substrate e-β-Ga2O3 single crystal aqondiswe ekhwalithi ephezulu (010) anobukhulu obungu-500 μm kanye ne-XRD FWHM ngaphansi kwemizuzwana engu-150 ye-arc. I-substrate i-Sn doped noma i-Fe doped. I-substrate eqhubayo ene-Sn-doped ine-doping concentration engu-1E18 kuya ku-9E18cm−3, kuyilapho i-substrate ene-iron-doped semi-insulating ine-resistivity ephakeme kune-10E10 Ω cm.

2.2 Indlela ye-MOCVD

I-MOCVD isebenzisa amakhemikhali ensimbi angokwemvelo njengezinto zokwakha ukukhulisa amafilimu amancane, ngaleyo ndlela kufezwe ukukhiqizwa okukhulu kwezentengiselwano. Lapho kukhuliswa i-Ga2O3 kusetshenziswa indlela ye-MOCVD, i-trimethylgallium (TMGa), i-triethylgallium (TEGa) kanye ne-Ga (dipentyl glycol formate) kuvame ukusetshenziswa njengomthombo we-Ga, kuyilapho i-H2O, i-O2 noma i-N2O kusetshenziswa njengomthombo we-oxygen. Ukukhula kusetshenziswa le ndlela ngokuvamile kudinga amazinga okushisa aphezulu (>800°C). Lobu buchwepheshe bunamandla okufeza ukuhlushwa okuphansi kokuthwala kanye nokuhamba kwama-electron okushisa okuphezulu nokuphansi, ngakho-ke kubaluleke kakhulu ekuqalisweni kwamadivayisi kagesi e-β-Ga2O3 asebenza kahle kakhulu. Uma kuqhathaniswa nendlela yokukhula ye-MBE, i-MOCVD inenzuzo yokufeza amazinga okukhula aphezulu kakhulu amafilimu e-β-Ga2O3 ngenxa yezici zokukhula kokushisa okuphezulu kanye nokusabela kwamakhemikhali.

Umfanekiso 7 β-Ga2O3 (010) AFM isithombe

Umfanekiso 8 β-Ga2O3 Ubudlelwano phakathi kwe-μ kanye nokumelana kweshidi okulinganiswe yi-Hall kanye nokushisa

2.3 Indlela ye-HVPE

I-HVPE ubuchwepheshe obuvuthiwe be-epitaxial futhi busetshenziswe kabanzi ekukhuleni kwe-epitaxial kwama-semiconductor e-III-V compound. I-HVPE yaziwa ngezindleko zayo zokukhiqiza eziphansi, izinga lokukhula okusheshayo, kanye nobukhulu befilimu ephezulu. Kufanele kuqashelwe ukuthi i-HVPEβ-Ga2O3 ivame ukubonisa isimo sobuso obuqinile kanye nobuningi obukhulu beziphambeko zobuso kanye nemigodi. Ngakho-ke, izinqubo zokupholisha zamakhemikhali nezemishini ziyadingeka ngaphambi kokukhiqiza idivayisi. Ubuchwepheshe be-HVPE be-β-Ga2O3 epitaxy buvame ukusebenzisa i-GaCl ne-O2 yegesi njengezandulela zokukhuthaza ukusabela kokushisa okuphezulu kwe-(001) β-Ga2O3 matrix. Isithombe 9 sibonisa isimo sobuso kanye nezinga lokukhula kwefilimu ye-epitaxial njengomsebenzi wokushisa. Eminyakeni yamuva nje, i-Novel Crystal Technology Inc. yaseJapan ithole impumelelo enkulu kwezentengiselwano ku-HVPE homoepitaxial β-Ga2O3, enobukhulu bezingqimba ze-epitaxial obungu-5 kuya ku-10 μm kanye nosayizi we-wafer obungu-2 no-4 amayintshi. Ngaphezu kwalokho, ama-wafer e-HVPE β-Ga2O3 homoepitaxial angu-20 μm obukhulu akhiqizwe yi-China Electronics Technology Group Corporation nawo angene esigabeni sokuhweba.

Umfanekiso 9 Indlela ye-HVPE β-Ga2O3

2.4 Indlela ye-PLD

Ubuchwepheshe be-PLD busetshenziswa kakhulu ukufaka amafilimu e-oxide ayinkimbinkimbi kanye nezakhiwo ezihlukene. Ngesikhathi senqubo yokukhula kwe-PLD, amandla e-photon ahlanganiswa nezinto eziqondiwe ngenqubo yokukhishwa kwama-electron. Ngokungafani ne-MBE, izinhlayiya zomthombo we-PLD zakhiwa imisebe ye-laser enamandla aphezulu kakhulu (>100 eV) bese zifakwa ku-substrate efudumele. Kodwa-ke, ngesikhathi senqubo yokukhipha, ezinye izinhlayiya zamandla aphezulu zizothinta ngqo ubuso bezinto ezibonakalayo, zidale amaphutha amaphuzu futhi ngaleyo ndlela zinciphise ikhwalithi yefilimu. Ngokufanayo nendlela ye-MBE, i-RHEED ingasetshenziswa ukuqapha isakhiwo sobuso kanye nokwakheka kwezinto ngesikhathi sangempela ngesikhathi senqubo yokufakwa kwe-PLD β-Ga2O3, okuvumela abacwaningi ukuthi bathole ulwazi lokukhula ngokunembile. Indlela ye-PLD kulindeleke ukuthi ikhulise amafilimu e-β-Ga2O3 aqhuba kahle kakhulu, okwenza kube yisisombululo sokuxhumana se-ohmic esilungiselelwe kahle kumadivayisi kagesi e-Ga2O3.

Isithombe se-AFM esingu-10 se-Si doped Ga2O3

2.5 Indlela ye-MIST-CVD

I-MIST-CVD iwubuchwepheshe bokukhulisa ifilimu encane obulula futhi obungabizi kakhulu. Le ndlela ye-CVD ihilela ukusabela kokufutha i-atomized precursor ku-substrate ukuze kufezwe ukufakwa kwefilimu encane. Kodwa-ke, kuze kube manje, i-Ga2O3 ekhuliswe kusetshenziswa i-mist CVD isesenazo izakhiwo zikagesi ezinhle, okushiya isikhala esiningi sokuthuthukiswa nokwenza ngcono esikhathini esizayo.