Ama-semiconductor e-wide bandgap (WBG) amelwe yi-silicon carbide (SiC) kanye ne-gallium nitride (GaN) athole ukunakwa kabanzi. Abantu banamathemba aphezulu ngamathemba okusetshenziswa kwe-silicon carbide ezimotweni zikagesi kanye namagridi kagesi, kanye namathemba okusetshenziswa kwe-gallium nitride ekushajeni okusheshayo. Eminyakeni yamuva nje, ucwaningo ngezinto ze-Ga2O3, i-AlN kanye nedayimane luye lwenza intuthuko enkulu, okwenza izinto ze-semiconductor ze-bandgap ezibanzi kakhulu zibe yinto egxile kakhulu. Phakathi kwazo, i-gallium oxide (Ga2O3) iyinto evelayo ye-ultra-wide-bandgap semiconductor ene-band gap engu-4.8 eV, amandla ensimu yokuqhekeka okubucayi okucatshangelwayo angaba ngu-8 MV cm-1, ijubane lokugcwala elingaba ngu-2E7cm s-1, kanye ne-Baliga quality factor ephezulu engu-3000, ethola ukunakwa kabanzi emkhakheni we-voltage ephezulu kanye ne-high frequency power electronics.
1. Izici zezinto ze-Gallium oxide
I-Ga2O3 inegebe elikhulu lebhendi (4.8 eV), kulindeleke ukuthi ifinyelele kokubili amandla aphezulu okumelana ne-voltage kanye namandla aphezulu, futhi ingaba nekhono lokuzivumelanisa ne-voltage ephezulu ngokumelana okuphansi, okwenza kube yinto ebalulekile ocwaningweni lwamanje. Ngaphezu kwalokho, i-Ga2O3 ayinazo nje kuphela izakhiwo zezinto ezibonakalayo ezinhle kakhulu, kodwa futhi ihlinzeka ngobuchwepheshe obuhlukahlukene bokusebenzisa i-n-type doping obulungiseka kalula, kanye nokukhula kwe-substrate okungabizi kakhulu kanye nobuchwepheshe be-epitaxy. Kuze kube manje, kutholakale izigaba ezinhlanu ezahlukene zekristalu ku-Ga2O3, kufaka phakathi i-corundum (α), i-monoclinic (β), i-spinel enephutha (γ), i-cubic (δ) kanye nezigaba ze-orthorhombic (ɛ). Ukuqina kwe-thermodynamic, ngokulandelana, yi-γ, δ, α, ɛ, kanye ne-β. Kubalulekile ukuqaphela ukuthi i-monoclinic β-Ga2O3 iyona ezinzile kakhulu, ikakhulukazi emazingeni okushisa aphezulu, kanti ezinye izigaba zizinzile ngaphezu kokushisa kwegumbi futhi zivame ukuguquka zibe yisigaba se-β ngaphansi kwezimo ezithile zokushisa. Ngakho-ke, ukuthuthukiswa kwamadivayisi asekelwe ku-β-Ga2O3 sekuyinto ebaluleke kakhulu emkhakheni we-elekthronikhi yamandla eminyakeni yamuva nje.
Ithebula 1 Ukuqhathaniswa kwamanye amapharamitha ezinto ze-semiconductor
Isakhiwo sekristalu se-monoclinicβ-Ga2O3 siboniswe kuThebula 1. Amapharamitha ayo e-lattice afaka phakathi i-a = 12.21 Å, b = 3.04 Å, c = 5.8 Å, kanye ne-β = 103.8°. Iseli leyunithi liqukethe ama-athomu e-Ga(I) anokuhlanganiswa kwe-tetrahedral okusontekile kanye nama-athomu e-Ga(II) anokuhlanganiswa kwe-octahedral. Kunezinhlelo ezintathu ezahlukene zama-athomu e-oxygen ku-"twisted cubic" array, kufaka phakathi ama-athomu amabili e-O(I) ne-O(II) ahlanganiswe ngonxantathu kanye ne-athomu elilodwa le-O(III) elihlanganiswe ngonxantathu. Ukuhlanganiswa kwalezi zinhlobo ezimbili zokuhlanganiswa kwe-athomu kuholela ku-anisotropy ye-β-Ga2O3 enezakhiwo ezikhethekile ku-physics, ukugqwala kwamakhemikhali, i-optics kanye ne-electronics.
Umfanekiso 1 Umdwebo wesakhiwo se-monoclinic β-Ga2O3 crystal
Ngokombono we-energy band theory, inani eliphansi le-conduction band ye-β-Ga2O3 litholakala esimweni samandla esihambisana ne-4s0 hybrid orbit ye-athomu ye-Ga. Umehluko wamandla phakathi kwenani eliphansi le-conduction band kanye nezinga lamandla e-vacuum (i-electron affinity energy) ulinganiswa. ngu-4 eV. Isisindo se-electron esisebenzayo se-β-Ga2O3 silinganiswa njengo-0.28–0.33 me kanye ne-electronic conductivity yayo enhle. Kodwa-ke, i-valence band maximum ibonisa i-shallow Ek curve ene-curvature ephansi kakhulu kanye ne-O2p orbitals ezitholakala kakhulu, okuphakamisa ukuthi izimbobo zitholakala ngokujulile. Lezi zici zibeka inselele enkulu yokufeza i-p-type doping ku-β-Ga2O3. Ngisho noma i-P-type doping ingatholakala, i-hole μ ihlala isezingeni eliphansi kakhulu. 2. Ukukhula kwekristalu elilodwa le-gallium oxide elinobuningi Kuze kube manje, indlela yokukhula ye-β-Ga2O3 bulk single crystal substrate ngokuyinhloko iyindlela yokudonsa ikristalu, njenge-Czochralski (CZ), indlela yokudla ifilimu encane echazwe ngohlangothi (i-Edge -Defined film-fed, i-EFG), i-Bridgman (i-Bridgman, i-HB noma i-VB) kanye nobuchwepheshe be-floating zone (floating zone, i-FZ). Phakathi kwazo zonke izindlela, izindlela zokudla ze-Czochralski kanye nezindlela zokudla ifilimu encane echazwe ngohlangothi kulindeleke ukuthi zibe izindlela ezithembisayo kakhulu zokukhiqizwa kwama-wafer e-β-Ga 2O3 esikhathini esizayo, njengoba zingafinyelela ngesikhathi esisodwa amavolumu amakhulu kanye nobuningi obuphansi besici. Kuze kube manje, i-Novel Crystal Technology yaseJapan ithole i-matrix yezentengiselwano yokukhula kwe-melt β-Ga2O3.
1.1 Indlela yeCzochralski
Isimiso sendlela yeCzochralski ukuthi ungqimba lwembewu luqale lumbozwe, bese ikristalu elilodwa likhishwa kancane kancane ekuncibilikeni. Indlela yeCzochralski ibaluleke kakhulu ku-β-Ga2O3 ngenxa yokusebenza kwayo kahle kwezindleko, amakhono amakhulu, kanye nokukhula kwe-substrate yekhwalithi ephezulu yekristalu. Kodwa-ke, ngenxa yokucindezeleka kokushisa ngesikhathi sokukhula kwe-Ga2O3 okushisa okuphezulu, ukuhwamuka kwamakristalu angawodwa, izinto ezincibilikayo, kanye nomonakalo ku-Ir crucible kuzokwenzeka. Lokhu kungumphumela wobunzima bokufeza i-doping ephansi yohlobo lwe-n ku-Ga2O3. Ukwethula inani elifanele lomoya-mpilo emoyeni wokukhula kuyindlela eyodwa yokuxazulula le nkinga. Ngokusebenzisa kahle, i-β-Ga2O3 esezingeni eliphezulu engu-2-intshi enebanga lokuhlushwa kwama-electron lamahhala elingu-10^16~10^19 cm-3 kanye nobuningi obukhulu bama-electron obungu-160 cm2/Vs kukhuliswe ngempumelelo ngendlela yeCzochralski.
Umfanekiso 2 Ikristalu elilodwa le-β-Ga2O3 elikhuliswe ngendlela ye-Czochralski
1.2 Indlela yokondla ifilimu echazwe ngomphetho
Indlela yokondla ifilimu encane echazwe ngomphetho ibhekwa njengeyona ehola phambili ekukhiqizweni kwezentengiselwano kwezinto zekristalu eyodwa ze-Ga2O3 ezinkulu. Isimiso sale ndlela ukufaka ukuncibilika esikhumbeni nge-capillary slit, bese ukuncibilika kukhuphukela esikhumbeni ngesenzo se-capillary. Phezulu, ifilimu encane yakha futhi isakazeke kuzo zonke izinhlangothi ngenkathi ishukunyiswa ukuba ikhanye yikristalu yembewu. Ngaphezu kwalokho, imiphetho yengaphezulu lesikhunta ingalawulwa ukukhiqiza amakristalu kuma-flakes, amashubhu, noma kunoma iyiphi i-geometry oyifunayo. Indlela yokondla ifilimu encane echazwe ngomphetho ye-Ga2O3 inikeza amazinga okukhula okusheshayo kanye nobubanzi obukhulu. Isithombe 3 sibonisa umdwebo wekristalu eyodwa ye-β-Ga2O3. Ngaphezu kwalokho, ngokwesilinganiso sosayizi, ama-substrate angu-2-intshi kanye nama-intshi angu-4 e-β-Ga2O3 anokukhanya okuhle kakhulu kanye nokufana aye athengiswa, kuyilapho i-substrate engu-6-intshi iboniswa ocwaningweni lokuthengiswa kwesikhathi esizayo. Muva nje, izinto ezinkulu eziyindilinga zekristalu eyodwa nazo sezitholakale ngokuqondiswa (−201). Ngaphezu kwalokho, indlela yokondla ifilimu echazwe ngomphetho we-β-Ga2O3 iphinde ikhuthaze ukuxutshwa kwezinto zensimbi ezishintshayo, okwenza ucwaningo nokulungiswa kwe-Ga2O3 kube nokwenzeka.
Umfanekiso 3 β-Ga2O3 ikristalu eyodwa ekhuliswe ngendlela yokondla ifilimu echazwe ngomphetho
1.3 Indlela yeBridgeman
Ngendlela yeBridgeman, amakristalu akhiwa ku-crucible eshukunyiswa kancane kancane nge-gradient yokushisa. Le nqubo ingenziwa ngendlela evundlile noma eqondile, ngokuvamile kusetshenziswa i-crucible ejikelezayo. Kubalulekile ukuqaphela ukuthi le ndlela ingasebenzisa noma ingasebenzisi imbewu yekristalu. Abaqhubi bendabuko beBridgman abanakho ukubona ngqo izinqubo zokukhula kokuncibilika nokwekristalu futhi kumele balawule amazinga okushisa ngokunemba okuphezulu. Indlela yeBridgman eqondile isetshenziswa kakhulu ekukhuleni kwe-β-Ga2O3 futhi yaziwa ngekhono layo lokukhula endaweni yomoya. Ngesikhathi senqubo yokukhula kwendlela yeBridgman eqondile, ukulahlekelwa okuphelele kwesisindo se-melt ne-crucible kugcinwa ngaphansi kwe-1%, okuvumela ukukhula kwamakristalu amakhulu e-β-Ga2O3 ngokulahlekelwa okuncane.
Umfanekiso 4 Ikristalu elilodwa le-β-Ga2O3 elikhuliswe ngendlela yeBridgeman
1.4 Indlela yendawo entantayo
Indlela ye-floating zone ixazulula inkinga yokungcoliswa kwekristalu ngezinto ezisetshenziswa ekushiseni okuphezulu futhi inciphisa izindleko eziphezulu ezihambisana nezisetshenziswa ezisetshenziswa ekushiseni okuphezulu ze-infrared. Phakathi nale nqubo yokukhula, ukuncibilika kungashiswa ngesibani kunomthombo we-RF, ngaleyo ndlela kube lula izidingo zemishini yokukhula. Nakuba ukuma kanye nekhwalithi yekristalu ye-β-Ga2O3 ekhuliswe ngendlela ye-floating zone kungakabi ngcono, le ndlela ivula indlela ethembisayo yokutshala i-β-Ga2O3 ehlanzekile kakhulu ibe amakristalu angawodwa angabizi kakhulu.
Umfanekiso 5 β-Ga2O3 ikristalu elilodwa elikhuliswe ngendlela ye-floating zone.
Isikhathi sokuthunyelwe: Meyi-30-2024