Cov khoom siv hluav taws xob dav dav (WBG) uas sawv cev los ntawm silicon carbide (SiC) thiab gallium nitride (GaN) tau txais kev saib xyuas dav dav. Tib neeg muaj kev cia siab siab rau kev siv silicon carbide hauv cov tsheb fais fab thiab cov phiaj xwm fais fab, nrog rau kev siv gallium nitride hauv kev them ceev. Nyob rau xyoo tas los no, kev tshawb fawb txog Ga2O3, AlN thiab cov ntaub ntawv pob zeb diamond tau ua tiav zoo heev, ua rau cov ntaub ntawv semiconductor bandgap dav dav yog qhov tseem ceeb. Ntawm lawv, gallium oxide (Ga2O3) yog cov khoom siv semiconductor ultra-wide-bandgap tshiab nrog band gap ntawm 4.8 eV, lub zog theoretical critical breakdown field ntawm kwv yees li 8 MV cm-1, lub zog saturation ntawm kwv yees li 2E7cm s-1, thiab Baliga quality factor siab ntawm 3000, tau txais kev saib xyuas dav dav hauv kev lag luam ntawm cov khoom siv hluav taws xob siab thiab zaus siab.
1. Cov yam ntxwv ntawm cov khoom siv gallium oxide
Ga2O3 muaj qhov sib txawv loj (4.8 eV), xav tias yuav ua tiav ob qho tib si siab voltage thiab muaj peev xwm siab zog, thiab tuaj yeem muaj peev xwm hloov pauv voltage siab ntawm qhov tsis kam qis, ua rau lawv yog qhov tseem ceeb ntawm kev tshawb fawb tam sim no. Tsis tas li ntawd, Ga2O3 tsis yog tsuas yog muaj cov khoom siv zoo heev, tab sis kuj muab ntau yam kev hloov pauv n-hom doping yooj yim, nrog rau kev loj hlob substrate pheej yig thiab epitaxy technologies. Txog tam sim no, tsib theem siv lead ua sib txawv tau pom hauv Ga2O3, suav nrog corundum (α), monoclinic (β), defective spinel (γ), cubic (δ) thiab orthorhombic (ɛ) theem. Thermodynamic stabilities yog, raws li, γ, δ, α, ɛ, thiab β. Nws yog ib qho tsim nyog sau tseg tias monoclinic β-Ga2O3 yog qhov ruaj khov tshaj plaws, tshwj xeeb tshaj yog thaum kub siab, thaum lwm theem yog metastable saum chav tsev kub thiab feem ntau hloov mus rau hauv β theem nyob rau hauv cov xwm txheej thermal tshwj xeeb. Yog li ntawd, kev tsim cov khoom siv β-Ga2O3 tau dhau los ua qhov tseem ceeb hauv kev siv hluav taws xob hauv xyoo tas los no.
Rooj 1 Kev sib piv ntawm qee cov khoom siv semiconductor
Cov qauv siv lead ua ntawm monoclinicβ-Ga2O3 tau qhia nyob rau hauv Rooj 1. Nws cov lattice parameters suav nrog a = 12.21 Å, b = 3.04 Å, c = 5.8 Å, thiab β = 103.8°. Lub unit cell muaj Ga(I) atoms nrog twisted tetrahedral coordination thiab Ga(II) atoms nrog octahedral coordination. Muaj peb qhov kev npaj sib txawv ntawm cov pa oxygen atoms hauv "twisted cubic" array, suav nrog ob lub triangularly coordinated O(I) thiab O(II) atoms thiab ib lub tetrahedrally coordinated O(III) atom. Kev sib xyaw ua ke ntawm ob hom atomic coordination no ua rau anisotropy ntawm β-Ga2O3 nrog cov khoom tshwj xeeb hauv physics, tshuaj corrosion, optics thiab electronics.
Daim Duab 1 Daim duab qhia txog cov qauv ntawm monoclinic β-Ga2O3 siv lead ua ke
Los ntawm qhov kev xav ntawm lub zog band theory, qhov tsawg kawg nkaus ntawm conduction band ntawm β-Ga2O3 yog los ntawm lub xeev zog sib raug rau 4s0 hybrid orbit ntawm Ga atom. Qhov sib txawv ntawm lub zog ntawm qhov tsawg kawg nkaus ntawm conduction band thiab qib zog nqus tsev (electron affinity energy) yog ntsuas. yog 4 eV. Lub electron mass ntawm β-Ga2O3 yog ntsuas li 0.28–0.33 me thiab nws cov conductivity hluav taws xob zoo. Txawm li cas los xij, qhov siab tshaj plaws ntawm valence band qhia txog qhov nkhaus Ek ntiav nrog qhov nkhaus qis heev thiab muaj zog O2p orbitals, qhia tias cov qhov tob tob. Cov yam ntxwv no ua rau muaj kev cov nyom loj heev kom ua tiav p-hom doping hauv β-Ga2O3. Txawm tias P-hom doping tuaj yeem ua tiav, qhov μ tseem nyob ntawm qib qis heev. 2. Kev loj hlob ntawm cov pob zeb gallium oxide ib leeg siv lead ua ke Txog tam sim no, txoj kev loj hlob ntawm β-Ga2O3 ib leeg siv lead ua ke feem ntau yog siv lead ua ke rub txoj kev, xws li Czochralski (CZ), txoj kev pub zaub mov nyias nyias uas muaj ntug (Edge -Defined film-fed, EFG), Bridgman (rtical lossis horizontal Bridgman, HB lossis VB) thiab thaj chaw ntab (floating zone, FZ) thev naus laus zis. Ntawm txhua txoj kev, Czochralski thiab cov txheej txheem pub zaub mov nyias nyias uas muaj ntug yuav yog txoj hauv kev zoo tshaj plaws rau kev tsim cov wafers β-Ga 2O3 ntau hauv yav tom ntej, vim tias lawv tuaj yeem ua tiav cov ntim loj thiab cov qhov tsis zoo tsawg. Txog tam sim no, Nyiv Pooj Lub Tshuab Crystal Tshiab tau pom ib lub matrix lag luam rau kev loj hlob yaj β-Ga2O3.
1.1 Txoj kev Czochralski
Lub hauv paus ntsiab lus ntawm Czochralski txoj kev yog tias cov noob txheej raug npog ua ntej, thiab tom qab ntawd cov siv lead ua ib leeg maj mam rub tawm ntawm cov yaj. Txoj kev Czochralski tseem ceeb dua rau β-Ga2O3 vim nws qhov kev siv nyiaj tsim nyog, muaj peev xwm loj, thiab cov khoom siv lead ua zoo heev. Txawm li cas los xij, vim muaj kev ntxhov siab thermal thaum lub sijhawm kub siab ntawm Ga2O3, kev ua kom cov siv lead ua ib leeg, cov khoom siv yaj, thiab kev puas tsuaj rau Ir crucible yuav tshwm sim. Qhov no yog qhov tshwm sim ntawm qhov nyuaj hauv kev ua tiav n-hom doping qis hauv Ga2O3. Kev qhia cov pa oxygen kom tsim nyog rau hauv huab cua loj hlob yog ib txoj hauv kev los daws qhov teeb meem no. Los ntawm kev ua kom zoo dua, cov β-Ga2O3 zoo 2-nti nrog ntau yam electron dawb concentration ntawm 10 ^ 16 ~ 10 ^ 19 cm-3 thiab qhov siab tshaj plaws electron ceev ntawm 160 cm 2 / Vs tau loj hlob zoo los ntawm txoj kev Czochralski.
Daim Duab 2 Ib qho siv lead ua ke ntawm β-Ga2O3 uas loj hlob los ntawm txoj kev Czochralski
1.2 Txoj kev pub zaj duab xis uas txhais los ntawm ntug
Txoj kev pub cov zaj duab xis nyias uas muaj ntug txiav txim siab yog suav tias yog tus neeg sib tw ua tus thawj coj rau kev tsim khoom lag luam ntawm cov khoom siv Ga2O3 ib leeg loj hauv thaj chaw. Lub hauv paus ntsiab lus ntawm txoj kev no yog muab cov yaj tso rau hauv pwm nrog lub capillary slit, thiab cov yaj nce mus rau pwm los ntawm capillary action. Ntawm sab saum toj, ib zaj duab xis nyias tsim thiab nthuav dav rau txhua qhov kev taw qhia thaum raug ntxias kom crystallize los ntawm cov noob siv lead ua. Tsis tas li ntawd, cov npoo ntawm lub pwm sab saum toj tuaj yeem tswj tau los tsim cov siv lead ua flakes, raj, lossis txhua yam geometry xav tau. Txoj kev pub cov zaj duab xis nyias uas muaj ntug txiav txim siab ntawm Ga2O3 muab cov nqi loj hlob sai thiab cov kab uas hla loj. Daim duab 3 qhia txog daim duab ntawm β-Ga2O3 ib leeg siv lead ua. Tsis tas li ntawd, hais txog qhov loj me, 2-nti thiab 4-nti β-Ga2O3 substrates nrog kev pom tseeb zoo thiab kev sib xws tau ua lag luam, thaum 6-nti substrate tau pom hauv kev tshawb fawb rau kev lag luam yav tom ntej. Tsis ntev los no, cov khoom siv loj ib leeg siv lead ua kuj tau muaj nrog (-201) kev taw qhia. Tsis tas li ntawd xwb, txoj kev pub zaj duab xis β-Ga2O3 ntug kuj txhawb nqa kev doping ntawm cov hlau hloov pauv, ua rau kev tshawb fawb thiab kev npaj ntawm Ga2O3 ua tau.
Daim Duab 3 β-Ga2O3 ib leeg siv lead ua los ntawm txoj kev pub zaub mov uas txhais tau tias ntug
1.3 Txoj kev Bridgeman
Hauv txoj kev Bridgeman, cov siv lead ua tau tsim nyob rau hauv lub crucible uas maj mam txav mus los ntawm qhov kub thiab txias. Cov txheej txheem tuaj yeem ua tiav hauv kab rov tav lossis ntsug, feem ntau siv lub crucible tig. Nws tsim nyog sau cia tias txoj kev no yuav lossis tsis siv cov noob siv lead ua. Cov neeg ua haujlwm Bridgman ib txwm tsis muaj kev pom tseeb ntawm cov txheej txheem yaj thiab kev loj hlob ntawm cov siv lead ua thiab yuav tsum tswj qhov kub nrog qhov tseeb siab. Txoj kev ntsug Bridgman feem ntau yog siv rau kev loj hlob ntawm β-Ga2O3 thiab paub txog nws lub peev xwm los loj hlob hauv huab cua. Thaum lub sijhawm ntsug Bridgman txoj kev loj hlob, tag nrho cov qhov hnyav poob ntawm cov yaj thiab crucible raug khaws cia qis dua 1%, ua rau kev loj hlob ntawm cov siv lead ua loj β-Ga2O3 nrog qhov poob tsawg kawg nkaus.
Daim Duab 4 Ib qho siv lead ua ke ntawm β-Ga2O3 uas loj hlob los ntawm Bridgeman txoj kev
1.4 Txoj kev ua kom thaj chaw ntab
Txoj kev floating zone daws qhov teeb meem ntawm kev ua qias tuaj ntawm cov khoom siv crucible thiab txo cov nqi siab uas cuam tshuam nrog cov khoom siv infrared uas tiv taus kub siab. Thaum lub sijhawm loj hlob no, cov yaj tuaj yeem raug cua sov los ntawm lub teeb es tsis yog RF qhov chaw, yog li ua kom yooj yim rau cov khoom siv loj hlob. Txawm hais tias cov duab thiab cov khoom siv crystal zoo ntawm β-Ga2O3 uas loj hlob los ntawm txoj kev floating zone tseem tsis tau zoo tshaj plaws, txoj kev no qhib txoj hauv kev zoo rau kev loj hlob β-Ga2O3 uas muaj kev ntshiab siab rau hauv cov khoom siv crystal uas pheej yig.
Daim Duab 5 β-Ga2O3 ib lub siv lead ua los ntawm txoj kev floating zone.
Lub sijhawm tshaj tawm: Tsib Hlis-30-2024