Ii-semiconductors ze-wide bandgap (WBG) ezimelwe yi-silicon carbide (SiC) kunye ne-gallium nitride (GaN) zifumene ingqalelo ebanzi. Abantu banethemba elikhulu malunga namathuba okusetyenziswa kwe-silicon carbide kwizithuthi zombane kunye neegridi zamandla, kunye namathuba okusetyenziswa kwe-gallium nitride ekutshajeni ngokukhawuleza. Kwiminyaka yakutshanje, uphando kwi-Ga2O3, i-AlN kunye nezixhobo zedayimani luye lwenza inkqubela phambili enkulu, okwenza izixhobo ze-semiconductor ze-bandgap ezibanzi kakhulu zibe yeyona nto iphambili. Phakathi kwazo, i-gallium oxide (Ga2O3) sisixhobo se-semiconductor se-ultra-wide-bandgap esisandula kuvela esine-band gap ye-4.8 eV, amandla entsimi yokuqhekeka okubalulekileyo kwethiyori emalunga ne-8 MV cm-1, isantya sokugcwala esimalunga ne-2E7cm s-1, kunye ne-Baliga quality factor ephezulu ye-3000, efumana ingqalelo ebanzi kwicandelo le-voltage ephezulu kunye ne-high frequency power electronics.
1. Iimpawu zezinto zeGallium oxide
I-Ga2O3 ine-band gap enkulu (4.8 eV), kulindeleke ukuba ifikelele kuzo zombini i-voltage ephezulu kunye namandla aphezulu, kwaye inokuba nokukwazi ukuguquguquka kwe-voltage ephezulu xa ixhathisa kancinci, nto leyo eyenza ukuba ibe yeyona nto iphambili kuphando lwangoku. Ukongeza, i-Ga2O3 ayinazo nje kuphela iimpawu zezinto ezibonakalayo ezintle, kodwa ikwabonelela ngeendlela ezahlukeneyo zobuchwepheshe bokusebenzisa i-n-type doping ezilungisekayo ngokulula, kunye nobuchwepheshe bokukhula kwe-substrate obungabizi kakhulu kunye ne-epitaxy. Okwangoku, kufunyenwe ii-crystal phases ezintlanu ezahlukeneyo kwi-Ga2O3, kubandakanya i-corundum (α), i-monoclinic (β), i-spinel (γ) enesiphene, ii-cubic (δ) kunye ne-orthorhombic (ɛ). Uzinzo lwe-thermodynamic, ngokulandelelana, yi-γ, δ, α, ɛ, kunye ne-β. Kubalulekile ukuqaphela ukuba i-monoclinic β-Ga2O3 yeyona izinzileyo, ngakumbi kumaqondo obushushu aphezulu, ngelixa ezinye ii-phases zizinzile ngaphezu kobushushu begumbi kwaye zitshintsha zibe yi-β phase phantsi kweemeko ezithile zobushushu. Ngoko ke, uphuhliso lwezixhobo ezisekelwe kwi-β-Ga2O3 luye lwaba yinto ephambili ekugxilwe kuyo kwicandelo le-elektroniki yamandla kwiminyaka yakutshanje.
Itheyibhile 1 Uthelekiso lwezinye iiparameter zezinto ze-semiconductor
Isakhiwo sekristale se-monoclinicβ-Ga2O3 siboniswe kwiTheyibhile 1. Iiparameter zayo ze-lattice ziquka i-a = 12.21 Å, b = 3.04 Å, c = 5.8 Å, kunye ne-β = 103.8°. I-unit cell inee-athomu ze-Ga(I) ezine-twisted tetrahedral coordination kunye nee-athomu ze-Ga(II) ezine-octahedral coordination. Kukho amalungiselelo amathathu ahlukeneyo ee-athomu ze-oksijini kwi-"twisted cubic" array, kuquka ii-athomu ezimbini ze-O(I) kunye ne-O(II) ezidibeneyo ngonxantathu kunye ne-athomu enye ye-O(III) edibeneyo ngonxantathu. Ukudibana kwezi ntlobo zimbini ze-athomu coordination kukhokelela kwi-anisotropy ye-β-Ga2O3 eneempawu ezikhethekileyo kwi-physics, i-chemical corrosion, i-optics kunye ne-electronics.
Umfanekiso 1 Umzobo wolwakhiwo lweskimu lwekristale ye-monoclinic β-Ga2O3
Ngokwembono yethiyori yebhendi yamandla, ixabiso elincinci lebhendi yokuqhuba ye-β-Ga2O3 livela kwimeko yamandla ehambelana ne-4s0 hybrid orbit ye-atom ye-Ga. Umahluko wamandla phakathi kwexabiso elincinci lebhendi yokuqhuba kunye nenqanaba lamandla e-vacuum (amandla e-electron affinity) ulinganiswa. yi-4 eV. Ubunzima be-electron obusebenzayo be-β-Ga2O3 bulinganiswa njenge-0.28–0.33 me kunye nokuqhuba kwayo okuhle kwe-elektroniki. Nangona kunjalo, i-valence band maximum ibonisa i-shallow Ek curve ene-curvature ephantsi kakhulu kunye ne-O2p orbitals ezikwindawo eqinileyo, nto leyo ebonisa ukuba imingxunya ikwindawo enzulu. Ezi mpawu zibeka umngeni omkhulu ekufezekiseni i-p-type doping kwi-β-Ga2O3. Nokuba i-P-type doping inokufezekiswa, i-hole μ ihlala ikwinqanaba eliphantsi kakhulu. 2. Ukukhula kwe-bulk gallium oxide single crystal Okwangoku, indlela yokukhula ye-β-Ga2O3 bulk single crystal substrate ikakhulu yindlela yokutsala i-crystal, efana ne-Czochralski (CZ), indlela yokutya i-edge-defined thin film feeding (Edge-Defined film-fed, EFG), i-Bridgman (i-rtical okanye i-horizontal Bridgman, i-HB okanye i-VB) kunye netekhnoloji ye-floating zone (floating zone, FZ). Phakathi kwazo zonke iindlela, iindlela ze-Czochralski kunye neendlela zokutya i-thin-film feeding kulindeleke ukuba zibe zezona ndlela zithembisayo zokuvelisa ii-wafers ze-β-Ga 2O3 kwixesha elizayo, njengoko zinokufikelela ngaxeshanye kwiivolumu ezinkulu kunye noxinano oluphantsi lwesiphene. Ukuza kuthi ga ngoku, i-Novel Crystal Technology yaseJapan ifumene i-matrix yorhwebo yokukhula kwe-melt β-Ga2O3.
1.1 Indlela yeCzochralski
Umgaqo wendlela yeCzochralski kukuba umaleko wembewu uqale ugutyungelwe, uze emva koko ikristale enye ikhutshwe kancinci kwi-melt. Indlela yeCzochralski ibaluleke ngakumbi kwi-β-Ga2O3 ngenxa yokusebenza kwayo kakuhle kweendleko, amandla amakhulu, kunye nokukhula kwe-substrate esemgangathweni ophezulu wekristale. Nangona kunjalo, ngenxa yoxinzelelo lobushushu ngexesha lokukhula kobushushu obuphezulu beGa2O3, kuya kwenzeka ukufuma kweekristale ezizimeleyo, izinto ezinyibilikayo, kunye nomonakalo kwi-Ir crucible. Oku kungenxa yobunzima bokufezekisa i-doping ephantsi ye-n-type kwiGa2O3. Ukungenisa isixa esifanelekileyo seoksijini kwindawo yokukhula yenye indlela yokusombulula le ngxaki. Ngokwenza ngcono, i-β-Ga2O3 ekumgangatho ophezulu ene-2-intshi enoluhlu lwamandla e-electron asimahla lwe-10^16~10^19 cm-3 kunye nobuninzi be-electron obuphezulu be-160 cm2/Vs ikhuliswe ngempumelelo yindlela yeCzochralski.
Umfanekiso 2 Ikristale enye ye-β-Ga2O3 ekhuliswe ngendlela yeCzochralski
1.2 Indlela yokondla ifilimu echazwe kumda
Indlela yokondla ifilimu encinci echazwe ngomphetho ithathwa njengeyona nto iphambili ekuveliseni imveliso yezorhwebo yezinto zekristale enye yeGa2O3 enkulu. Umgaqo wale ndlela kukubeka inyibiliki kwisikhunta esine-capillary slit, kwaye inyibiliki inyuke iye kwisikhunta ngesenzo se-capillary. Phezulu, ifilimu encinci iyakheka kwaye isasazeke kuzo zonke iindlela ngelixa ikhuthazwa ukuba ikristale yikristale yembewu. Ukongeza, imiphetho yephezulu yesikhunta ingalawulwa ukuvelisa iikristale kwiiflakes, iityhubhu, okanye nayiphi na ijiyometri efunekayo. Indlela yokondla ifilimu encinci echazwe ngomphetho yeGa2O3 ibonelela ngamazinga okukhula ngokukhawuleza kunye nobubanzi obukhulu. Umfanekiso 3 ubonisa umzobo wekristale enye ye-β-Ga2O3. Ukongeza, ngokwesayizi yobukhulu, ii-substrates ze-β-Ga2O3 eziyi-2-intshi kunye ne-4-intshi ezine-transparent kunye nokufana ziye zathengiswa, ngelixa i-substrate eyi-6-intshi iboniswa kuphando lokuthengiswa kwixesha elizayo. Kutshanje, izinto ezinkulu ezijikelezayo zekristale enye nazo ziye zafumaneka nge-orientation (−201). Ukongeza, indlela yokondla ifilimu echazwe kumda we-β-Ga2O3 ikwakhuthaza ukusetyenziswa kwe-doping yezinto zesinyithi eziguqukayo, okwenza uphando kunye nokulungiswa kweGa2O3 kube nokwenzeka.
Umfanekiso 3 β-Ga2O3 ikristale enye ekhuliswe ngendlela yokondla ifilimu echazwe ngomphetho
1.3 Indlela yeBridgeman
Kwindlela yeBridgeman, iikristale zenziwa kwi-crucible eshukunyiswa kancinci kancinci nge-gradient yobushushu. Le nkqubo inokwenziwa ngendlela ethe tye okanye ethe nkqo, ngokuqhelekileyo kusetyenziswa i-crucible ejikelezayo. Kubalulekile ukuqaphela ukuba le ndlela ingasebenzisa okanye ingasebenzisi imbewu yekristale. Abaqhubi beBridgman bendabuko abanalo umboniso othe ngqo weenkqubo zokukhula kwe-melting kunye ne-crystal kwaye kufuneka balawule amaqondo obushushu ngokuchanekileyo okuphezulu. Indlela yeBridgman ethe tye isetyenziselwa kakhulu ukukhula kwe-β-Ga2O3 kwaye yaziwa ngokukwazi kwayo ukukhula kwindawo yomoya. Ngexesha lenkqubo yokukhula kwendlela yeBridgman ethe tye, ukulahleka kobunzima obupheleleyo be-melt kunye ne-crucible kugcinwa ngaphantsi kwe-1%, okuvumela ukukhula kweekristale ezinkulu ze-β-Ga2O3 kunye nokulahleka okuncinci.
Umfanekiso 4 Ikristale enye ye-β-Ga2O3 ekhuliswe ngendlela yeBridgeman
1.4 Indlela yendawo edadayo
Indlela ye-floating zone isombulula ingxaki yokungcoliswa kwekristale zizinto ezisetyenziswa ekutshiseni kwaye inciphisa iindleko eziphezulu ezinxulumene nee-infrared crucibles ezimelana nobushushu obuphezulu. Ngexesha lale nkqubo yokukhula, ukunyibilika kunokufudunyezwa sisibane endaweni yomthombo we-RF, ngaloo ndlela kwenza kube lula iimfuno zezixhobo zokukhula. Nangona imo kunye nomgangatho wekristale we-β-Ga2O3 okhuliswe yindlela ye-floating zone zingekabi semgangathweni, le ndlela ivula indlela ethembisayo yokukhulisa i-β-Ga2O3 ecocekileyo kakhulu ibe ziikristale ezingabizi kakhulu.
Umfanekiso 5 β-Ga2O3 ikristale enye ekhuliswe ngendlela ye-floating zone.
Ixesha lokuthumela: Meyi-30-2024