Cov noob qoob loo uas tau oxidized thiab kev loj hlob ntawm epitaxial-Ⅱ

2. Kev loj hlob ntawm cov yeeb yaj kiab nyias nyias Epitaxial

Lub substrate muab ib txheej txhawb nqa lub cev lossis txheej conductive rau Ga2O3 cov khoom siv fais fab. Txheej tseem ceeb tom ntej yog txheej channel lossis txheej epitaxial siv rau kev tiv thaiv voltage thiab kev thauj mus los ntawm cov neeg nqa khoom. Yuav kom nce qhov hluav taws xob tawg thiab txo qhov kev tiv thaiv conduction, qhov tuab thiab doping concentration, nrog rau qhov zoo tshaj plaws ntawm cov khoom siv, yog qee qhov yuav tsum tau ua ua ntej. Cov txheej Ga2O3 epitaxial zoo feem ntau raug tso rau hauv kev siv molecular beam epitaxy (MBE), metal organic chemical vapor deposition (MOCVD), halide vapor deposition (HVPE), pulsed laser deposition (PLD), thiab fog CVD based deposition techniques.

Rooj 2 Qee cov thev naus laus zis epitaxial sawv cev

2.1 Txoj kev MBE

MBE thev naus laus zis muaj npe nrov rau nws lub peev xwm los cog cov yeeb yaj kiab β-Ga2O3 zoo, tsis muaj qhov tsis zoo nrog n-hom doping tswj tau vim nws qhov chaw nqus tsev siab heev thiab cov khoom siv huv siab. Yog li ntawd, nws tau dhau los ua ib qho ntawm cov thev naus laus zis β-Ga2O3 nyias zaj duab xis deposition uas tau kawm ntau tshaj plaws thiab muaj peev xwm ua lag luam. Tsis tas li ntawd, txoj kev MBE kuj tau npaj ua tiav cov txheej txheem heterostructure β-(AlXGa1-X)2O3/Ga2O3 nyias zaj duab xis zoo, qis-doped. MBE tuaj yeem saib xyuas cov qauv nto thiab morphology hauv lub sijhawm tiag tiag nrog atomic txheej precision los ntawm kev siv reflection siab zog electron diffraction (RHEED). Txawm li cas los xij, β-Ga2O3 zaj duab xis cog siv MBE thev naus laus zis tseem ntsib ntau yam teeb meem, xws li kev loj hlob qis thiab qhov loj me zaj duab xis me. Kev tshawb fawb pom tias qhov kev loj hlob yog nyob rau hauv qhov kev txiav txim ntawm (010)>(001)>(-201)>(100). Nyob rau hauv me ntsis Ga-nplua nuj tej yam kev mob ntawm 650 txog 750 ° C, β-Ga2O3 (010) qhia txog kev loj hlob zoo tshaj plaws nrog rau qhov chaw du thiab kev loj hlob sai. Siv txoj kev no, β-Ga2O3 epitaxy tau ua tiav nrog RMS roughness ntawm 0.1 nm. β-Ga2O3 Hauv ib puag ncig Ga-nplua nuj, MBE zaj duab xis loj hlob ntawm ntau qhov kub sib txawv tau pom hauv daim duab. Novel Crystal Technology Inc. tau ua tiav epitaxially tsim 10 × 15mm2 β-Ga2O3MBE wafers. Lawv muab cov khoom siv zoo (010) oriented β-Ga2O3 ib leeg siv lead ua substrates nrog lub thickness ntawm 500 μm thiab XRD FWHM hauv qab 150 arc vib nas this. Lub substrate yog Sn doped lossis Fe doped. Lub substrate conductive Sn-doped muaj qhov doping concentration ntawm 1E18 txog 9E18cm−3, thaum lub substrate semi-insulating uas muaj hlau doped muaj qhov resistivity siab dua 10E10 Ω cm-2.

2.2 Txoj kev MOCVD

MOCVD siv cov hlau organic sib xyaw ua cov khoom siv ua ntej los cog cov zaj duab xis nyias, yog li ua tiav kev tsim khoom lag luam loj. Thaum cog Ga2O3 siv txoj kev MOCVD, trimethylgallium (TMGa), triethylgallium (TEGa) thiab Ga (dipentyl glycol formate) feem ntau yog siv ua qhov chaw Ga, thaum H2O, O2 lossis N2O yog siv ua qhov chaw oxygen. Kev loj hlob siv txoj kev no feem ntau xav tau qhov kub siab (> 800 ° C). Cov thev naus laus zis no muaj peev xwm ua tiav qhov kev sib sau ua ke qis thiab qhov kub siab thiab qis electron mobility, yog li nws tseem ceeb heev rau kev paub txog cov khoom siv fais fab β-Ga2O3 ua tau zoo. Piv nrog rau txoj kev loj hlob MBE, MOCVD muaj qhov zoo ntawm kev ua tiav cov nqi loj hlob siab heev ntawm β-Ga2O3 zaj duab xis vim yog cov yam ntxwv ntawm kev loj hlob kub siab thiab cov tshuaj lom neeg.

Daim duab 7 β-Ga2O3 (010) AFM duab

Daim Duab 8 β-Ga2O3 Kev sib raug zoo ntawm μ thiab daim ntawv tsis kam ntsuas los ntawm Hall thiab kub

2.3 Txoj kev HVPE

HVPE yog ib qho thev naus laus zis epitaxial uas paub tab thiab tau siv dav hauv kev loj hlob epitaxial ntawm III-V compound semiconductors. HVPE paub txog nws cov nqi tsim khoom qis, kev loj hlob sai, thiab zaj duab xis tuab. Nws yuav tsum tau sau tseg tias HVPEβ-Ga2O3 feem ntau qhia txog cov qauv ntawm qhov chaw ntxhib thiab qhov ceev ntawm qhov tsis zoo thiab qhov av. Yog li ntawd, cov txheej txheem tshuaj lom neeg thiab kev kho tshuab yuav tsum tau ua ntej tsim cov cuab yeej. HVPE thev naus laus zis rau β-Ga2O3 epitaxy feem ntau siv cov pa roj GaCl thiab O2 ua cov khoom siv ua ntej los txhawb qhov kub siab ntawm (001) β-Ga2O3 matrix. Daim duab 9 qhia txog qhov xwm txheej ntawm qhov chaw thiab kev loj hlob ntawm zaj duab xis epitaxial ua haujlwm ntawm qhov kub. Nyob rau hauv xyoo tas los no, Nyiv lub Novel Crystal Technology Inc. tau ua tiav kev lag luam zoo hauv HVPE homoepitaxial β-Ga2O3, nrog cov txheej epitaxial tuab ntawm 5 txog 10 μm thiab wafer loj ntawm 2 thiab 4 nti. Tsis tas li ntawd xwb, 20 μm tuab HVPE β-Ga2O3 homoepitaxial wafers uas tsim los ntawm Tuam Tshoj Electronics Technology Group Corporation kuj tau nkag mus rau theem kev lag luam.

Daim Duab 9 HVPE txoj kev β-Ga2O3

2.4 Txoj kev PLD

Cov thev naus laus zis PLD feem ntau yog siv los tso cov yeeb yaj kiab oxide nyuaj thiab cov qauv sib txawv. Thaum lub sijhawm PLD txoj kev loj hlob, lub zog photon tau txuas nrog cov khoom siv los ntawm cov txheej txheem tso tawm hluav taws xob. Hauv kev sib piv rau MBE, cov khoom me me PLD yog tsim los ntawm kev siv hluav taws xob laser nrog lub zog siab heev (> 100 eV) thiab tom qab ntawd tso rau ntawm lub substrate sov. Txawm li cas los xij, thaum lub sijhawm ablation, qee cov khoom me me muaj zog yuav cuam tshuam ncaj qha rau qhov chaw ntawm cov khoom, tsim cov qhov tsis zoo thiab yog li txo qhov zoo ntawm cov yeeb yaj kiab. Zoo ib yam li txoj kev MBE, RHEED tuaj yeem siv los saib xyuas cov qauv ntawm qhov chaw thiab morphology ntawm cov khoom siv hauv lub sijhawm tiag tiag thaum lub sijhawm PLD β-Ga2O3 deposition txheej txheem, tso cai rau cov kws tshawb fawb kom tau txais cov ntaub ntawv loj hlob kom raug. Txoj kev PLD xav tias yuav loj hlob cov yeeb yaj kiab β-Ga2O3 conductive heev, ua rau nws yog qhov kev daws teeb meem ohmic contact zoo tshaj plaws hauv Ga2O3 cov khoom siv hluav taws xob.

Daim Duab 10 AFM duab ntawm Si doped Ga2O3

2.5 Txoj kev MIST-CVD

MIST-CVD yog ib txoj kev siv tshuab ua kom cov zaj duab xis nyias nyias yooj yim thiab pheej yig. Txoj kev CVD no suav nrog kev tshuaj tsuag cov tshuaj ua ntej rau ntawm lub substrate kom ua tiav cov zaj duab xis nyias nyias. Txawm li cas los xij, txog tam sim no, Ga2O3 uas siv cov tshuaj CVD uas muaj huab cua tseem tsis muaj cov khoom siv hluav taws xob zoo, uas ua rau muaj ntau qhov chaw rau kev txhim kho thiab kev ua kom zoo dua yav tom ntej.