1. Peb tiam semiconductors
Thawj tiam semiconductor technology tau tsim los ntawm cov khoom siv semiconductor xws li Si thiab Ge. Nws yog cov khoom siv hauv paus rau kev txhim kho cov transistors thiab kev siv hluav taws xob sib xyaw ua ke. Thawj cov khoom siv semiconductor tau tsim lub hauv paus rau kev lag luam hluav taws xob hauv xyoo pua 20th thiab yog cov ntaub ntawv yooj yim rau kev siv hluav taws xob sib txuas.
Cov khoom siv semiconductor thib ob feem ntau suav nrog gallium arsenide, indium phosphide, gallium phosphide, indium arsenide, aluminium arsenide thiab lawv cov ternary compounds. Cov khoom siv semiconductor thib ob yog lub hauv paus ntawm kev lag luam xov xwm optoelectronic. Rau lub hauv paus no, muaj feem xyuam rau kev lag luam xws li teeb pom kev zoo, zaub, laser, thiab photovoltaics tau tsim. Lawv tau siv dav hauv cov ntaub ntawv xov xwm niaj hnub thiab optoelectronic zaub kev lag luam.
Cov ntaub ntawv sawv cev ntawm cov khoom siv semiconductor thib peb muaj xws li gallium nitride thiab silicon carbide. Vim lawv qhov sib txawv ntawm qhov sib txawv, siab electron saturation drift velocity, high thermal conductivity, thiab siab tawg teb lub zog, lawv yog cov khoom zoo tagnrho rau kev npaj high-power density, high-frequency, thiab low-loss electronic devices. Ntawm lawv, silicon carbide cov khoom siv hluav taws xob muaj qhov zoo ntawm lub zog loj, kev siv hluav taws xob tsawg, thiab qhov me me, thiab muaj cov ntawv thov dav dav hauv tsheb tshiab, photovoltaics, tsheb thauj mus los, cov ntaub ntawv loj, thiab lwm yam. Gallium nitride RF pab kiag li lawm muaj qhov zoo ntawm cov zaus, siab zog, dav bandwidth, tsawg zog siv thiab me me, thiab muaj dav daim ntawv thov kev cia siab nyob rau hauv 5G kev sib txuas lus, Internet ntawm tej yam, tub rog radar thiab lwm yam teb. Tsis tas li ntawd, cov cuab yeej siv hluav taws xob gallium nitride tau siv dav hauv qhov hluav taws xob tsawg. Tsis tas li ntawd, nyob rau hauv xyoo tas los no, cov khoom siv gallium oxide tshwm sim yuav tsum tsim kom muaj kev sib xyaw ua ke nrog SiC thiab GaN thev naus laus zis uas twb muaj lawm, thiab muaj peev xwm thov kev cia siab nyob rau hauv qhov tsawg-zaus thiab high-voltage teb.
Piv nrog rau cov khoom siv semiconductor thib ob, cov khoom siv semiconductor thib peb muaj qhov dav bandgap dav (qhov bandgap dav ntawm Si, ib yam khoom siv ntawm thawj tiam semiconductor khoom, yog li 1.1eV, bandgap dav ntawm GaAs, ib txwm muaj. Cov khoom siv ntawm cov khoom siv semiconductor thib ob, yog kwv yees li 1.42eV, thiab bandgap dav ntawm GaN, ib yam khoom siv ntawm cov khoom siv semiconductor thib peb, yog siab dua 2.3eV), muaj zog hluav taws xob tiv thaiv, muaj zog tiv thaiv hluav taws xob tawg, thiab kub tsis kam. Cov khoom siv semiconductor thib peb uas muaj qhov dav dav bandgap tshwj xeeb yog tsim rau kev tsim hluav taws xob-resistant, high-frequency, high-power thiab high-integration-density electronic devices. Lawv cov ntawv thov hauv microwave xov tooj cua zaus, LEDs, lasers, cov cuab yeej hluav taws xob thiab lwm yam kev lag luam tau nyiam ntau yam, thiab lawv tau pom cov kev loj hlob dav dav hauv kev sib txuas lus hauv xov tooj, cov phiajcim ntse, tsheb ciav hlau, tsheb tshiab, cov khoom siv hluav taws xob, thiab ultraviolet thiab xiav. -Green light devices [1].
Duab qhov chaw: CASA, Zheshang Securities Research Institute
Daim duab 1 GaN lub zog ntaus ntawv lub sij hawm teev thiab kev kwv yees
II GaN cov qauv thiab cov yam ntxwv
GaN yog ib tug ncaj bandgap semiconductor. Lub bandgap dav ntawm lub wurtzite qauv ntawm chav tsev kub yog hais txog 3.26eV. GaN cov ntaub ntawv muaj peb lub ntsiab siv lead ua, uas yog wurtzite qauv, sphalerite qauv thiab pob zeb ntsev qauv. Ntawm lawv, cov qauv wurtzite yog cov qauv siv lead ua ruaj khov tshaj plaws. Daim duab 2 yog daim duab ntawm hexagonal wurtzite qauv ntawm GaN. Cov qauv wurtzite ntawm GaN cov khoom belongs rau hexagonal kaw-packed qauv. Txhua chav cell muaj 12 atoms, suav nrog 6 N atoms thiab 6 Ga atoms. Txhua Ga (N) atom tsim ib daim ntawv cog lus nrog 4 ze tshaj N (Ga) atoms thiab yog stacked nyob rau hauv qhov kev txiav txim ntawm ABABAB… raws [0001] kev taw qhia [2].
Daim duab 2 Wurtzite qauv GaN siv lead ua cell daim duab
III Feem ntau siv substrates rau GaN epitaxy
Nws zoo nkaus li tias homogeneous epitaxy ntawm GaN substrates yog qhov kev xaiv zoo tshaj plaws rau GaN epitaxy. Txawm li cas los xij, vim yog lub zog loj ntawm GaN, thaum qhov kub nce mus txog qhov melting point ntawm 2500 ℃, nws qhov sib thooj decomposition siab yog li 4.5Gpa. Thaum lub siab decomposition qis dua qhov siab, GaN tsis yaj tab sis decomposes ncaj qha. Qhov no ua rau paub tab substrate npaj thev naus laus zis xws li Czochralski txoj kev tsis tsim nyog rau kev npaj ntawm GaN ib leeg siv lead ua substrates, ua GaN substrates nyuaj rau huab hwm coj tsim thiab kim. Yog li ntawd, cov substrates feem ntau siv hauv GaN epitaxial kev loj hlob yog feem ntau Si, SiC, sapphire, thiab lwm yam. [3].
Daim duab 3 GaN thiab cov khoom siv feem ntau siv substrate
GaN epitaxy ntawm sapphire
Sapphire muaj cov tshuaj ruaj khov, pheej yig, thiab muaj kev loj hlob ntawm kev lag luam loj loj. Yog li ntawd, nws tau dhau los ua ib qho ntawm qhov ntxov tshaj plaws thiab feem ntau siv cov khoom siv hauv cov khoom siv hluav taws xob semiconductor. Raws li ib qho ntawm feem ntau siv substrates rau GaN epitaxy, cov teeb meem tseem ceeb uas yuav tsum tau daws rau sapphire substrates yog:
✔ Vim yog lub lattice loj tsis sib haum ntawm sapphire (Al2O3) thiab GaN (kwv yees li 15%), qhov tsis xws luag ntawm qhov sib cuam tshuam ntawm txheej epitaxial thiab substrate yog siab heev. Txhawm rau txo nws qhov tsis zoo, lub substrate yuav tsum tau ua rau kev kho mob nyuaj ua ntej cov txheej txheem epitaxy pib. Ua ntej yuav loj hlob GaN epitaxy ntawm sapphire substrates, lub substrate nto yuav tsum tau ua ntej yuav tsum tau nruj me ntsis ntxuav kom tshem tawm cov kab mob, residual polishing puas, thiab lwm yam, thiab tsim cov kauj ruam thiab cov kauj ruam nto lug. Tom qab ntawd, lub substrate nto yog nitrided los hloov cov khoom ntub dej ntawm txheej epitaxial. Thaum kawg, txheej nyias nyias AlN tsis (feem ntau yog 10-100nm tuab) yuav tsum tau muab tso rau ntawm lub substrate nto thiab annealed ntawm qis kub los npaj rau qhov kawg epitaxial loj hlob. Txawm li cas los xij, qhov sib txawv ntawm qhov ntom ntom ntawm GaN epitaxial films loj hlob ntawm sapphire substrates tseem siab dua li ntawm homoepitaxial films (txog 1010cm-2, piv nrog qhov tseem ceeb xoom dislocation ceev hauv silicon homoepitaxial films lossis gallium arsenide homoepitaxial films 102-102 cm, los yog nruab nrab ntawm 1010cm-2. 2). Qhov siab dua qhov tsis xws luag txo cov neeg nqa khoom txav, yog li ua rau cov neeg nqa khoom tsawg lub neej thiab txo cov thermal conductivity, tag nrho cov uas yuav txo cov cuab yeej ua haujlwm [4];
✔ Lub thermal expansion coefficient ntawm sapphire yog ntau dua li ntawm GaN, yog li biaxial compressive kev nyuaj siab yuav raug tsim nyob rau hauv lub epitaxial txheej thaum lub sij hawm cov txheej txheem ntawm txias los ntawm deposition kub mus rau chav tsev kub. Rau cov yeeb yaj kiab epitaxial tuab, qhov kev ntxhov siab no yuav ua rau tawg ntawm zaj duab xis lossis txawm tias lub substrate;
Piv nrog rau lwm cov substrates, lub thermal conductivity ntawm sapphire substrates yog qis dua (li 0.25W * cm-1 * K-1 ntawm 100 ℃), thiab cov cua kub dissipation kev ua tau zoo yog tsis zoo;
✔ Vim nws cov conductivity tsis zoo, sapphire substrates tsis haum rau lawv kev koom ua ke thiab siv nrog lwm yam khoom siv semiconductor.
Txawm hais tias qhov tsis xws luag ntawm GaN epitaxial txheej loj hlob ntawm sapphire substrates yog siab, nws tsis zoo li txo qhov kev ua haujlwm optoelectronic ntawm GaN-raws li xiav-ntsuab LEDs, yog li sapphire substrates tseem yog feem ntau siv substrates rau GaN-raws li LEDs.
Nrog rau kev txhim kho ntawm ntau daim ntawv thov tshiab ntawm GaN li xws li lasers lossis lwm yam khoom siv hluav taws xob siab, qhov tsis xws luag ntawm sapphire substrates tau dhau los ua qhov txwv ntawm lawv daim ntawv thov. Tsis tas li ntawd, nrog kev txhim kho ntawm SiC substrate kev loj hlob thev naus laus zis, kev txo nqi thiab kev loj hlob ntawm GaN epitaxial thev naus laus zis ntawm Si substrates, kev tshawb fawb ntxiv txog kev loj hlob ntawm GaN epitaxial txheej ntawm sapphire substrates tau maj mam qhia txog qhov txias txias.
GaN epitaxy ntawm SiC
Piv nrog rau sapphire, SiC substrates (4H- thiab 6H-crystals) muaj ib tug me me lattice mismatch nrog GaN epitaxial khaubncaws sab nraud povtseg (3.1%, sib npaug rau [0001] taw qhia epitaxial films), ntau dua thermal conductivity (kwv yees 3.8W * cm-1 * K -1), thiab lwm yam. Tsis tas li ntawd, cov conductivity ntawm SiC substrates kuj tso cai rau kev sib cuag hluav taws xob ua nyob rau sab nraum qab ntawm lub substrate, uas yuav pab kom yooj yim rau cov txheej txheem ntaus ntawv. Lub hav zoov ntawm cov txiaj ntsig no tau nyiam ntau thiab ntau tus kws tshawb fawb los ua haujlwm ntawm GaN epitaxy ntawm silicon carbide substrates.
Txawm li cas los xij, ua haujlwm ncaj qha rau SiC substrates kom tsis txhob loj hlob GaN epilayers kuj ntsib ntau qhov tsis zoo, suav nrog cov hauv qab no:
✔ Qhov roughness ntawm SiC substrates yog siab dua li ntawm sapphire substrates (sapphire roughness 0.1nm RMS, SiC roughness 1nm RMS), SiC substrates muaj siab hardness thiab tsis zoo ua hauj lwm, thiab qhov roughness thiab residual polishing puas yog ib qho ntawm cov qhov chaw ntawm qhov tsis xws luag hauv GaN epilayers.
✔ Cov ntsia hlau dislocation ceev ntawm SiC substrates yog siab (dislocation ceev 103-104cm-2), ntsia hlau dislocations yuav propagate rau GaN epilayer thiab txo cov cuab yeej kev ua tau zoo;
✔ Lub atomic kev npaj ntawm lub substrate nto induces tsim ntawm stacking faults (BSFs) nyob rau hauv lub GaN epilayer. Rau epitaxial GaN ntawm SiC substrates, muaj ntau yam ua tau atomic kev txiav txim ntawm lub substrate, uas ua rau inconsistent thawj atomic stacking kev txiav txim ntawm epitaxial GaN txheej rau nws, uas yog nquag mus stacking faults. Stacking faults (SFs) qhia cov khoom siv hluav taws xob ua ke raws li c-axis, ua rau muaj teeb meem xws li xau ntawm cov khoom sib cais hauv lub dav hlau;
✔ Lub thermal expansion coefficient ntawm SiC substrate yog me dua li ntawm AlN thiab GaN, uas ua rau thermal stress tsub zuj zuj ntawm cov epitaxial txheej thiab substrate thaum lub sij hawm txias txheej txheem. Waltereit thiab Hom tau kwv yees raws li lawv cov kev tshawb fawb tau pom tias qhov teeb meem no tuaj yeem daws tau los ntawm kev loj hlob GaN epitaxial txheej ntawm nyias, coherently strained AlN nucleation txheej;
✔ Qhov teeb meem ntawm cov dej tsis zoo ntawm Ga atoms. Thaum loj hlob GaN epitaxial khaubncaws sab nraud povtseg ncaj qha rau ntawm SiC nto, vim tsis zoo wettability ntawm ob lub atoms, GaN yog nquag mus rau 3D kob loj hlob ntawm lub substrate nto. Kev nthuav qhia ib txheej tsis yog cov tshuaj uas siv ntau tshaj plaws los txhim kho qhov zoo ntawm cov ntaub ntawv epitaxial hauv GaN epitaxy. Qhia txog AlN lossis AlxGa1-xN tsis txheej txheej tuaj yeem txhim kho qhov ntub dej ntawm SiC nto thiab ua rau GaN epitaxial txheej loj hlob hauv ob qhov ntev. Tsis tas li ntawd, nws tseem tuaj yeem tswj hwm kev ntxhov siab thiab tiv thaiv cov substrate tsis xws luag los ntawm kev txuas mus rau GaN epitaxy;
✔ Kev npaj thev naus laus zis ntawm SiC substrates tsis paub tab, tus nqi substrate yog siab, thiab muaj ob peb tus neeg muag khoom thiab cov khoom siv me me.
Torres li al. txoj kev tshawb fawb qhia tau hais tias etching SiC substrate nrog H2 ntawm qhov kub thiab txias (1600 ° C) ua ntej epitaxy tuaj yeem tsim cov qauv kev txiav txim ntau dua rau ntawm qhov chaw substrate, yog li tau txais AlN epitaxial zaj duab xis zoo dua li thaum nws ncaj qha. loj hlob ntawm thawj substrate nto. Xie thiab nws pab neeg txoj kev tshawb fawb kuj qhia tau hais tias etching pretreatment ntawm silicon carbide substrate tuaj yeem txhim kho cov morphology nto thiab siv lead ua zoo ntawm GaN epitaxial txheej. Smith et al. pom tias threading dislocations originating los ntawm substrate / tsis txheej thiab tsis txheej / epitaxial txheej interfaces muaj feem xyuam rau lub flatness ntawm lub substrate [5].
Daim duab 4 TEM morphology ntawm GaN epitaxial txheej cov qauv cog rau ntawm 6H-SiC substrate (0001) nyob rau hauv cov kev kho deg sib txawv (a) tshuaj ntxuav; (b) tshuaj ntxuav + hydrogen plasma kho; (c) tshuaj ntxuav + hydrogen plasma kho + 1300 ℃ hydrogen kho cua sov rau 30min
GaN epitaxy ntawm Si
Piv nrog silicon carbide, sapphire thiab lwm yam substrates, cov txheej txheem silicon substrate npaj yog paub tab, thiab nws muaj peev xwm stably muab mature loj-loj substrates nrog cov nqi siab. Nyob rau tib lub sij hawm, cov thermal conductivity thiab hluav taws xob conductivity yog zoo, thiab Si electronic device txheej txheem yog mature. Qhov ua tau zoo ntawm kev sib koom ua ke ntawm optoelectronic GaN li nrog Si hluav taws xob yav tom ntej kuj ua rau kev loj hlob ntawm GaN epitaxy ntawm silicon zoo nkauj heev.
Txawm li cas los xij, vim muaj qhov sib txawv loj hauv cov lattice tas li ntawm Si substrate thiab GaN cov khoom, heterogeneous epitaxy ntawm GaN ntawm Si substrate yog ib qho loj tsis sib haum xeeb epitaxy, thiab nws kuj yuav tsum tau ntsib ntau yam teeb meem:
✔ Nto interface zog teeb meem. Thaum GaN loj hlob ntawm Si substrate, saum npoo ntawm Si substrate yuav xub tau nitrided los ua ib qho amorphous silicon nitride txheej uas tsis haum rau cov nucleation thiab kev loj hlob ntawm high-density GaN. Tsis tas li ntawd, Si nto yuav ua ntej hu rau Ga, uas yuav corrode nto ntawm Si substrate. Thaum qhov kub thiab txias, qhov decomposition ntawm Si nto yuav diffuse mus rau hauv GaN epitaxial txheej los tsim cov xim dub silicon.
✔ Lub lattice tas li tsis sib haum xeeb ntawm GaN thiab Si yog qhov loj (~ 17%), uas yuav ua rau muaj kev sib txuam ntawm high-density threading dislocations thiab txo qhov zoo ntawm epitaxial txheej;
Piv nrog Si, GaN muaj cov thermal expansion coefficient loj dua (GaN's thermal expansion coefficient yog li 5.6 × 10-6K-1, Si's thermal expansion coefficient yog li 2.6 × 10-6K-1), thiab cov kab nrib pleb tuaj yeem tsim hauv GaN epitaxial txheej thaum lub sij hawm txias ntawm lub epitaxial kub rau chav tsev kub;
✔ Si reacts nrog NH3 ntawm qhov kub thiab txias los tsim polycrystalline SiNx. AlN tsis tuaj yeem tsim lub hauv paus zoo tshaj plaws ntawm lub hauv paus ntawm polycrystalline SiNx, uas ua rau muaj kev cuam tshuam tsis zoo ntawm GaN txheej tom qab cog thiab muaj ntau qhov tsis xws luag, ua rau tsis zoo siv lead ua ntawm GaN epitaxial txheej, thiab txawm tias nyuaj rau kev tsim ib leeg-crystalline. GaN epitaxial txheej [6]
Yuav kom daws tau qhov teeb meem ntawm qhov loj lattice mismatch, cov kws tshawb fawb tau sim ua kom paub cov ntaub ntawv xws li AlAs, GaAs, AlN, GaN, ZnO, thiab SiC ua cov txheej tsis nyob ntawm Si substrates. Txhawm rau kom tsis txhob tsim cov polycrystalline SiNx thiab txo nws cov teebmeem tsis zoo ntawm cov khoom siv lead ua zoo ntawm GaN / AlN / Si (111), TMAL feem ntau yuav tsum tau qhia rau qee lub sijhawm ua ntej epitaxial loj hlob ntawm AlN tsis txheej. txhawm rau tiv thaiv NH3 los ntawm kev hnov mob nrog Si ntog los ua SiNx. Tsis tas li ntawd, cov thev naus laus zis xws li cov qauv txheej txheem txheej txheem txheej txheem txheej txheem txheej txheem los txhim kho qhov zoo ntawm cov txheej ecitaxial. Kev txhim kho ntawm cov thev naus laus zis no pab txhawm rau txhawm rau tsim SiNx ntawm epitaxial interface, txhawb kev loj hlob ntawm ob sab ntawm GaN epitaxial txheej, thiab txhim kho kev loj hlob zoo ntawm txheej epitaxial. Tsis tas li ntawd, ib txheej txheej AlN tsis yog qhia los them rau qhov kev ntxhov siab tensile los ntawm qhov sib txawv ntawm thermal expansion coefficients kom tsis txhob muaj kab nrib pleb hauv GaN epitaxial txheej ntawm silicon substrate. Krost txoj kev tshawb fawb qhia tau hais tias muaj kev sib raug zoo ntawm cov tuab ntawm AlN tsis muaj txheej txheem thiab kev txo qis hauv strain. Thaum cov txheej txheej tsis tuab txog 12nm, txheej txheej epitaxial tuab dua 6μm tuaj yeem loj hlob ntawm silicon substrate los ntawm txoj kev loj hlob tsim nyog yam tsis muaj txheej txheej epitaxial tawg.
Tom qab kev siv zog mus ntev los ntawm cov kws tshawb fawb, qhov zoo ntawm GaN epitaxial txheej loj hlob ntawm silicon substrates tau txhim kho zoo, thiab cov khoom siv xws li cov nyhuv transistors, Schottky barrier ultraviolet detectors, xiav-ntsuab LEDs thiab ultraviolet lasers tau ua tiav tseem ceeb.
Nyob rau hauv cov ntsiab lus, txij li feem ntau siv GaN epitaxial substrates yog tag nrho cov heterogeneous epitaxy, lawv txhua tus ntsib teeb meem xws li lattice mismatch thiab loj sib txawv nyob rau hauv thermal expansion coefficients mus rau txawv degrees. Homogeneous epitaxial GaN substrates raug txwv los ntawm kev loj hlob ntawm kev siv tshuab, thiab cov substrates tseem tsis tau tsim tawm ntau. Tus nqi tsim khoom yog siab, lub substrate loj me me, thiab lub substrate zoo tsis zoo tagnrho. Txoj kev loj hlob ntawm GaN epitaxial substrates tshiab thiab kev txhim kho ntawm epitaxial zoo tseem yog ib qho tseem ceeb ntawm kev txwv txoj kev loj hlob ntxiv ntawm GaN epitaxial kev lag luam.
IV. Cov hau kev rau GaN epitaxy
MOCVD (Tshuaj vapor deposition)
Nws zoo nkaus li tias homogeneous epitaxy ntawm GaN substrates yog qhov kev xaiv zoo tshaj plaws rau GaN epitaxy. Txawm li cas los xij, txij li qhov precursors ntawm cov tshuaj vapor deposition yog trimethylgallium thiab ammonia, thiab cov pa roj carbon monoxide yog hydrogen, qhov kev loj hlob ntawm MOCVD yog li ntawm 1000-1100 ℃, thiab qhov kev loj hlob ntawm MOCVD yog li ntawm ob peb microns ib teev. Nws tuaj yeem tsim cov kev sib tshuam ntawm cov qib atomic, uas yog qhov tsim nyog rau kev loj hlob heterojunctions, quantum qhov dej, superlattices thiab lwm yam qauv. Nws txoj kev loj hlob sai, zoo sib xws, thiab tsim nyog rau thaj chaw loj thiab ntau qhov kev loj hlob yog feem ntau siv hauv kev tsim khoom.
MBE (molecular beam epitaxy)
Hauv molecular beam epitaxy, Ga siv lub hauv paus ntsiab lus, thiab nquag nitrogen tau los ntawm nitrogen los ntawm RF plasma. Piv nrog rau MOCVD txoj kev, MBE kev loj hlob kub yog li 350-400 ℃ qis dua. Qhov kev loj hlob qis dua tuaj yeem zam qee yam kev ua qias tuaj uas tuaj yeem tshwm sim los ntawm qhov kub thiab txias. MBE system ua haujlwm nyob rau hauv lub tshuab nqus tsev ultra-siab, uas tso cai rau nws los ua ke ntau txoj hauv kev nrhiav kom pom hauv qhov chaw. Nyob rau tib lub sijhawm, nws qhov kev loj hlob thiab kev tsim muaj peev xwm tsis tuaj yeem piv nrog MOCVD, thiab nws tau siv ntau dua hauv kev tshawb fawb tshawb fawb [7].
Daim duab 5 (a) Eiko-MBE schematic (b) MBE lub ntsiab tshuaj tiv thaiv chamber schematic
HVPE txoj kev (hydride vapor theem epitaxy)
Cov precursors ntawm hydride vapor theem epitaxy txoj kev yog GaCl3 thiab NH3. Detchprohm et al. siv txoj kev no los loj hlob ib txheej GaN epitaxial ntau pua ntawm microns tuab rau saum npoo ntawm sapphire substrate. Hauv lawv qhov kev sim, ib txheej ntawm ZnO tau loj hlob ntawm sapphire substrate thiab txheej epitaxial raws li ib txheej tsis, thiab txheej epitaxial tau tev tawm ntawm lub substrate nto. Piv nrog rau MOCVD thiab MBE, qhov tseem ceeb ntawm HVPE txoj kev yog nws txoj kev loj hlob siab, uas tsim nyog rau kev tsim cov txheej tuab thiab cov ntaub ntawv ntau. Txawm li cas los xij, thaum lub thickness ntawm cov epitaxial txheej tshaj 20μm, cov txheej txheem epitaxial tsim los ntawm txoj kev no yuav ua rau tawg.
Akira USUI tau nthuav tawm cov qauv txheej txheem substrate raws li txoj kev no. Lawv thawj zaug loj hlob nyias 1-1.5μm tuab GaN epitaxial txheej ntawm sapphire substrate siv txoj kev MOCVD. Cov txheej txheej epitaxial muaj 20nm tuab GaN tsis txheej zus nyob rau hauv qhov kub thiab txias thiab ib txheej GaN loj hlob nyob rau hauv kub kub. Tom qab ntawd, ntawm 430 ℃, ib txheej ntawm SiO2 tau plated rau saum npoo ntawm txheej epitaxial, thiab cov kab txaij qhov rais tau ua rau ntawm SiO2 zaj duab xis los ntawm photolithography. Cov kab txaij sib nrug yog 7μm thiab daim npog qhov dav ntawm 1μm txog 4μm. Tom qab qhov kev txhim kho no, lawv tau txais GaN epitaxial txheej ntawm 2-nti inch sapphire substrate uas tsis muaj tawg thiab zoo li daim iav txawm tias qhov tuab tau nce mus rau kaum lossis ntau pua microns. Qhov tsis xws luag raug txo los ntawm 109-1010cm-2 ntawm txoj kev HVPE ib txwm mus txog 6 × 107cm-2. Lawv kuj tau taw qhia hauv qhov kev sim uas thaum qhov kev loj hlob ntau tshaj 75μm / h, tus qauv saum npoo yuav dhau los ua ntxhib [8].
Daim duab 6 Graphical Substrate Schematic
V. Summary thiab Outlook
GaN cov ntaub ntawv pib tshwm sim hauv 2014 thaum lub teeb xiav LED yeej qhov khoom plig Nobel hauv Physics xyoo ntawd, thiab nkag mus rau pej xeem txoj kev them nqi ceev ceev hauv cov khoom siv hluav taws xob. Qhov tseeb, cov ntawv thov hauv lub tshuab hluav taws xob thiab RF cov cuab yeej siv hauv 5G hauv paus chaw nres tsheb uas tib neeg feem ntau pom tsis tau kuj tau tshwm sim ntsiag to. Nyob rau hauv xyoo tas los no, qhov kev ua tiav ntawm GaN-based automotive-qib fais fab khoom siv yuav tsum qhib cov ntsiab lus loj hlob tshiab rau GaN cov ntaub ntawv thov kev lag luam.
Qhov kev xav tau ntawm kev lag luam loj yuav muaj tseeb txhawb kev txhim kho ntawm GaN ntsig txog kev lag luam thiab thev naus laus zis. Nrog rau kev loj hlob thiab kev txhim kho ntawm GaN-txog kev lag luam saw, cov teeb meem ntsib los ntawm GaN epitaxial technology tam sim no nws thiaj li yuav txhim kho lossis kov yeej. Nyob rau hauv lub neej yav tom ntej, tib neeg yuav muaj tseeb tsim ntau dua tshiab epitaxial technologies thiab ntau zoo heev substrate xaiv. Los ntawm qhov ntawd, tib neeg yuav tuaj yeem xaiv qhov tsim nyog tshaj plaws kev tshawb fawb sab nraud technology thiab substrate rau txawv daim ntawv thov scenarios raws li cov yam ntxwv ntawm daim ntawv thov scenarios, thiab tsim cov khoom sib tw customized.
Post lub sij hawm: Jun-28-2024