1. Isizukulwana sesithathu semiconductors
I-teknoloji ye-semiconductor yesizukulwana sokuqala yaphuhliswa ngokusekelwe kwizinto ze-semiconductor ezifana ne-Si kunye ne-Ge. Yisiseko sezinto eziphathekayo zokuphuhliswa kwee-transistors kunye neteknoloji yesekethe edibeneyo. Izixhobo ze-semiconductor zesizukulwana sokuqala zibeka isiseko soshishino lwe-elektroniki kwi-20th inkulungwane kwaye zizinto ezisisiseko zeteknoloji yesekethe edibeneyo.
Izixhobo ze-semiconductor zesizukulwana sesibini ziquka i-gallium arsenide, i-indium phosphide, i-gallium phosphide, i-indium arsenide, i-aluminium arsenide kunye ne-ternary compounds. Izixhobo ze-semiconductor zesizukulwana sesibini zisisiseko soshishino lolwazi lwe-optoelectronic. Ngesi siseko, amashishini anxulumeneyo afana nokukhanyisa, ukubonisa, i-laser, kunye ne-photovoltaics aphuhlisiwe. Zisetyenziswa ngokubanzi kwitekhnoloji yolwazi lwangoku kunye namashishini omboniso we-optoelectronic.
Izinto ezimele izinto ze-semiconductor zesizukulwana sesithathu ziquka i-gallium nitride kunye ne-silicon carbide. Ngenxa yomsantsa wabo webhendi ebanzi, isantya esiphezulu se-electron saturation drift, i-thermal conductivity ephezulu, kunye nokomelela kwebala lokuqhekeka okuphezulu, zizinto ezifanelekileyo zokulungiselela uxinano lwamandla aphezulu, i-high-frequency, kunye nelahleko ephantsi yezixhobo zombane. Phakathi kwazo, izixhobo zamandla e-silicon carbide zinezibonelelo zokuxinana kwamandla aphezulu, ukusetyenziswa kwamandla aphantsi, kunye nobukhulu obuncinci, kwaye zinethemba elibanzi lesicelo kwizithuthi zamandla amatsha, i-photovoltaics, uthutho lukaloliwe, idatha enkulu, kunye nezinye iindawo. Izixhobo ze-Gallium nitride RF zineenzuzo ze-frequency ephezulu, amandla aphezulu, i-bandwidth ebanzi, ukusetyenziswa kwamandla aphantsi kunye nobukhulu obuncinci, kwaye banamathuba okusebenza okubanzi kunxibelelwano lwe-5G, i-Intanethi yezinto, i-radar yezempi kunye nezinye iindawo. Ukongezelela, izixhobo zamandla ezisekelwe kwi-gallium nitride zisetyenziswe ngokubanzi kwintsimi ye-voltage ephantsi. Ukongeza, kwiminyaka yakutshanje, izinto ezikhulayo ze-gallium oxide kulindeleke ukuba zenze ukuhambelana kobugcisa kunye nobuchwepheshe obukhoyo be-SiC kunye ne-GaN, kwaye zibe nethuba lokufaka isicelo kwiindawo eziphantsi kunye ne-high-voltage fields.
Xa kuthelekiswa nezixhobo ze-semiconductor zesizukulwana sesibini, izixhobo ze-semiconductor zesizukulwana sesithathu zinobubanzi obubanzi be-bandgap (ububanzi be-bandgap ye-Si, into eqhelekileyo yezinto ze-semiconductor yesizukulwana sokuqala, malunga ne-1.1eV, ububanzi be-bandgap ye-GaAs, eqhelekileyo Izinto eziphathekayo ze-semiconductor yesizukulwana sesibini, malunga ne-1.42eV, kunye nobubanzi be-bandgap I-GaN, into eqhelekileyo yezinto ze-semiconductor yesizukulwana sesithathu, ingaphezulu kwe-2.3eV), ukuxhathisa okunamandla kwi-radiation, ukuchasana okunamandla ekuqhekekeni kombane, kunye nokumelana nokushisa okuphezulu. Izinto ze-semiconductor zesizukulwana sesithathu ezinobubanzi obubanzi be-bandgap zifanelekile ngokukodwa kwimveliso ye-radiation-resistant, high-frequency, high-power and high-integration-density electronic devices. Ukusetyenziswa kwabo kwizixhobo zerediyo zerediyo ye-microwave, ii-LED, iilaser, izixhobo zombane kunye namanye amasimi atsale umdla omkhulu, kwaye babonise amathemba ophuhliso olubanzi kunxibelelwano oluphathwayo, iigridi ezihlakaniphile, ukuhamba ngololiwe, izithuthi zamandla amatsha, i-elektroniki yabathengi, kunye ne-ultraviolet kunye neblue. -izixhobo zokukhanya eziluhlaza [1].
Umthombo womfanekiso: CASA, Zheshang Securities Research Institute
Umzobo 1 GaN isixhobo amandla isikali ixesha kunye noqikelelo
II I-GaN yesakhiwo sezinto kunye neempawu
I-GaN yi-semiconductor ye-bandgap ngqo. Ububanzi be-bandgap yesakhiwo se-wurtzite kwiqondo lokushisa lokushisa malunga ne-3.26eV. Izixhobo ze-GaN zinezakhiwo ezintathu eziphambili zekristale, ezizezi isakhiwo se-wurtzite, isakhiwo se-sphalerite kunye nesakhiwo setyuwa yelitye. Phakathi kwabo, isakhiwo se-wurtzite sisona sakhiwo sekristale esizinzile. Umfanekiso wesi-2 ngumzobo wesakhiwo se-wurtzite esinehexagonal ye-GaN. Isakhiwo se-wurtzite sezinto ze-GaN zesakheko esinehexagonal esivalelekileyo. Iyunithi yeseli nganye ineathom ezili-12, kuquka iiathom ezi-N ezi-6 kunye ne-athom ezi-6 zeGa. I-atom nganye ye-Ga (N) yenza iqhina kunye ne-4 ekufutshane neeathom ze-N (Ga) kwaye zibekwe ngokolandelelwano lwe-ABABAB… ecaleni [0001] icala [2].
Umzobo we-2 isakhiwo seWurtzite I-GaN crystal cell diagram
III Ii-substrates ezisetyenziswa ngokuqhelekileyo kwi-GaN epitaxy
Kubonakala ngathi i-epitaxy ye-homogeneous kwi-substrates ye-GaN lolona khetho lulungileyo lwe-GaN epitaxy. Nangona kunjalo, ngenxa yamandla amakhulu ebhondi ye-GaN, xa ubushushu bufikelela kwindawo yokunyibilika ye-2500 ℃, uxinzelelo lwayo lokubola oluhambelanayo malunga ne-4.5GPa. Xa uxinzelelo lokubola lungaphantsi kolu xinzelelo, i-GaN ayinyibiliki kodwa ibola ngokuthe ngqo. Oku kwenza ubugcisa bokulungiselela i-substrate evuthiweyo efana nendlela ye-Czochralski engafanelekanga ukulungiselela i-GaN enye ye-crystal substrates, okwenza i-GaN substrates ibe nzima ukuvelisa ubuninzi kunye neendleko. Ngoko ke, i-substrates esetyenziswa ngokuqhelekileyo ekukhuleni kwe-GaN epitaxial ikakhulu iSi, iSiC, isafire, njl. [3].
Itshathi ye-3 ye-GaN kunye neeparamitha zezinto ezisetyenziswa ngokuqhelekileyo ze-substrate
I-GaN epitaxy kwisafire
ISapphire ineempawu zeekhemikhali ezizinzile, ingabizi kakhulu, kwaye inokukhula okuphezulu kwishishini lemveliso elikhulu. Ke ngoko, iye yaba yenye yezona zixhobo zakuqala kunye nezona zisetyenziswa kakhulu kwisixhobo sobunjineli semiconductor. Njengenye yeesubstrates ezisetyenziswa ngokuqhelekileyo kwiGaN epitaxy, ezona ngxaki ziphambili ekufuneka zisonjululwe kwisapphire substrates zezi:
✔ Ngenxa yokungahambelani kwelathisi enkulu phakathi kwesafire (Al2O3) kunye ne-GaN (malunga ne-15%), ukuxinana kwesiphene kwi-interface phakathi kwe-epitaxial layer kunye ne-substrate iphezulu kakhulu. Ukuze kuncitshiswe iziphumo zayo ezimbi, i-substrate kufuneka ifakwe kwi-pretreatment eyinkimbinkimbi ngaphambi kokuba inkqubo ye-epitaxy iqale. Ngaphambi kokukhula kwe-GaN epitaxy kwi-sapphire substrates, i-substrate surface kufuneka iqale icocwe ngokungqongqo ukususa ukungcola, umonakalo oseleyo wokupolisha, njl., kunye nokuvelisa amanyathelo kunye nezakhiwo zesinyathelo. Emva koko, i-substrate surface i-nitrided ukutshintsha iimpawu zokumanzisa kwe-epitaxial layer. Okokugqibela, umaleko obhityileyo we-AlN buffer (odla ngokuba yi-10-100nm ubukhulu) kufuneka ufakwe kumphezulu we-substrate kwaye ufakwe kwiqondo lobushushu eliphantsi ukulungiselela ukukhula kokugqibela kwe-epitaxial. Nangona kunjalo, ukuxinana kwe-dislocation kwiifilimu ze-GaN epitaxial ezikhuliswe kwi-sapphire substrates zisephezulu kuneefilimu ze-homoepitaxial (malunga ne-1010cm-2, xa kuthelekiswa ne-zero dislocation density kwi-silicon homoepitaxial films okanye i-gallium arsenide homoepitaxial02cm, kunye ne-10cm-2. 2). Uxinaniso oluphezulu lweziphene lunciphisa ukushukumiseka komthwali, ngaloo ndlela lunciphisa ubomi bomthwali abambalwa kunye nokunciphisa ukuhanjiswa kwe-thermal, konke oku kuya kunciphisa ukusebenza kwesixhobo [4];
✔ I-coefficient yokwandisa i-thermal yesafire inkulu kune-GaN, ngoko ke uxinzelelo lwe-biaxial compressive luya kuveliswa kwi-epitaxial layer ngexesha lenkqubo yokupholisa ukusuka kwiqondo lokushisa kwi-deposit ukuya kwiqondo lokushisa. Kwiifilimu ezinzulu ze-epitaxial, olu xinzelelo lunokubangela ukuqhekeka kwefilimu okanye nakwi-substrate;
✔ Xa kuthelekiswa namanye ama-substrates, i-thermal conductivity ye-sapphire substrates iphantsi (malunga ne-0.25W * cm-1 * K-1 kwi-100 ℃), kwaye ukusebenza kokutshatyalaliswa kobushushu kubi;
✔ Ngenxa yokungahambi kakuhle kwayo, i-sapphire substrates ayihambisani nokudibanisa kunye nokusebenza kunye nezinye izixhobo ze-semiconductor.
Nangona ingxinano yesiphene ye-GaN epitaxial layers ekhule kwi-sapphire substrates iphezulu, ayibonakali inciphisa kakhulu ukusebenza kwe-optoelectronic ye-GaN-based blue-green LEDs, ngoko ke i-sapphire substrates isasetyenziswa ngokuqhelekileyo kwii-LED ezisekelwe kwi-GaN.
Ngophuhliso lwezicelo ezitsha ezingakumbi zezixhobo ze-GaN ezinje ngelases okanye ezinye izixhobo zamandla ezixinanisene kakhulu, iziphene zendalo zesafire substrates ziye zanda zaba sisithintelo kwisicelo sazo. Ukongeza, ngophuhliso lwetekhnoloji yokukhula kwe-substrate ye-SiC, ukuncitshiswa kweendleko kunye nokuvuthwa kwetekhnoloji ye-GaN epitaxial kwi-substrates ye-Si, uphando olongezelelweyo malunga nokukhula kwe-GaN epitaxial layers kwii-sapphire substrates ziye zabonisa ngokuthe ngcembe umkhwa wokupholisa.
I-GaN epitaxy kwi-SiC
Xa kuthelekiswa nesafire, ii-substrates ze-SiC (4H- kunye ne-6H-crystals) zine-lattice encinci yokungahambi kakuhle kunye ne-GaN epitaxial layers (i-3.1%, ilingana ne- [0001] i-epitaxial films), i-thermal conductivity ephezulu (malunga ne-3.8W * cm-1 * K) -1), njl. Ukongeza, i-conductivity ye-SiC substrates ivumela ukuba unxibelelwano lombane lwenziwe ngasemva kwe-substrate, enceda ukwenza lula isakhiwo sesixhobo. Ubukho bezi nzuzo buye batsala abaphandi abaninzi ngakumbi ukuba basebenze kwi-GaN epitaxy kwi-silicon carbide substrates.
Nangona kunjalo, ukusebenza ngokuthe ngqo kwii-substrates ze-SiC ukunqanda ukukhula kwee-epilayers ze-GaN kukwajongene nothotho lwezinto ezingeloncedo, kubandakanywa oku kulandelayo:
✔ Uburhabaxa bomphezulu be-SiC substrates buphezulu kakhulu kunobo besapphire substrates (uburhabaxa besafire 0.1nm RMS, SiC roughness 1nm RMS), ii substrates zeSiC zinobulukhuni obuphezulu kunye nokusebenza kakubi kokusebenza, kwaye obu burhabaxa kunye nomonakalo oshiyekileyo wokupolisha ungomnye we imithombo yeziphene kwii-epilayers ze-GaN.
✔ I-screw dislocation density ye-SiC substrates iphezulu (i-dislocation density 103-104cm-2), i-screw dislocations inokusasaza kwi-epilayer ye-GaN kunye nokunciphisa ukusebenza kwesixhobo;
✔ Ukulungelelaniswa kwe-athomu kumphezulu we-substrate kubangela ukubunjwa kweempazamo zokupakisha (BSFs) kwi-epilayer ye-GaN. Kwi-epitaxial GaN kwii-substrates ze-SiC, kukho ii-odolo ezininzi ze-athom ezinokwenzeka kwi-substrate, ekhokelela ekungahambelani kokuqala kokupakishwa kwe-atom ye-epitaxial GaN umaleko kuyo, othanda ukupakisha iimpazamo. Iimpazamo zokupakisha (ii-SFs) zazisa iindawo zombane ezakhelwe ngaphakathi ecaleni kwe-c-axis, ekhokelela kwiingxaki ezinjengokuvuza kwezixhobo zokuzahlula kwinqwelomoya;
✔ I-coefficient yokwandisa i-thermal ye-substrate ye-SiC incinci kune-AlN kunye ne-GaN, ebangela ukuqokelela uxinzelelo lwe-thermal phakathi kwe-epitaxial layer kunye ne-substrate ngexesha lokupholisa. UWaltereit kunye noBrand baqikelele ngokusekelwe kwiziphumo zabo zophando ukuba le ngxaki ingancitshiswa okanye isonjululwe ngokukhula kweGaN epitaxial layers kwiileya ezibhityileyo, ezidityanisiweyo ngokudibeneyo ze-AlN nucleation;
✔ Ingxaki yokumanzisa kakubi kweeathom zeGa. Xa kukhula i-GaN epitaxial layers ngqo kwi-SiC surface, ngenxa yokungabi namanzi okumanzi phakathi kwee-athomu ezimbini, i-GaN ixhomekeke ekukhuleni kwesiqithi se-3D kwi-substrate surface. Ukwazisa i-buffer layer sesona sisombululo sisetyenziswa ngokuqhelekileyo ukuphucula umgangatho wezinto ze-epitaxial kwi-GaN epitaxy. Ukwazisa i-AlN okanye i-AlxGa1-xN ye-buffer layer inokuphucula ngokufanelekileyo ukumanzi kwe-SiC surface kwaye yenza i-GaN epitaxial layer ikhule kwimilinganiselo emibini. Ukongeza, inokulawula uxinzelelo kwaye ithintele iziphene ze-substrate ukusuka kwi-epitaxy ye-GaN;
✔ Itekhnoloji yokulungiselela i-SiC substrates ikhulile, ixabiso le-substrate liphezulu, kwaye bambalwa ababoneleli kunye nokubonelela okuncinci.
Uphando lukaTorres et al lubonisa ukuba ukufaka i-substrate ye-SiC kunye ne-H2 kwiqondo lokushisa eliphezulu (1600 ° C) ngaphambi kokuba i-epitaxy ikwazi ukuvelisa ulwakhiwo oluyalelwe ngakumbi kwi-substrate surface, ngaloo ndlela ifumana umgangatho ophezulu wefilimu ye-AlN epitaxial kunokuba ithe ngqo. ikhule kumphezulu we-substrate wokuqala. U-Xie kunye nophando lweqela lakhe lukwabonisa ukuba i-etching pretreatment ye-silicon carbide substrate inokuphucula kakhulu i-morphology yomphezulu kunye nomgangatho wekristale yomaleko we-GaN epitaxial. USmith et al. ufumanise ukuba ukutsalwa kwe-dislocations evela kwi-substrate/buffer layer kunye ne-buffer layer/epitaxial layer interfaces zinxulumene nokucaba kwe-substrate [5].
Umzobo we-4 TEM morphology yeesampuli ze-GaN epitaxial layer ezikhulile kwi-6H-SiC substrate (0001) phantsi kweemeko ezahlukeneyo zonyango lomhlaba (a) ukucocwa kweekhemikhali; (b) ukucocwa kweekhemikhali + unyango lwe-hydrogen plasma; (c) ukucocwa kweekhemikhali + unyango lweplasma ye-hydrogen + 1300℃ unyango lobushushu lwe-hydrogen lwe-30min
GaN epitaxy kwi Si
Xa kuthelekiswa ne-silicon carbide, isafire kunye nezinye ii-substrate, inkqubo yokulungiselela i-silicon substrate ikhulile, kwaye inokubonelela ngokuzinzileyo ii-substrates ezinobungakanani obukhulu kunye nokusebenza kweendleko eziphezulu. Kwangaxeshanye, i-thermal conductivity kunye ne-electrical conductivity ilungile, kwaye inkqubo ye-Si elektroniki yesixhobo ivuthiwe. Ukukwazi ukudibanisa ngokugqibeleleyo izixhobo ze-optoelectronic GaN kunye nezixhobo zombane ze-Si kwixesha elizayo nako kwenza ukukhula kwe-GaN epitaxy kwi-silicon ibe nomtsalane kakhulu.
Nangona kunjalo, ngenxa yomahluko omkhulu kwii-lattice constants phakathi kwe-Si substrate kunye ne-GaN material, i-heterogeneous epitaxy ye-GaN kwi-Si substrate yi-epitaxy enkulu engafaniyo, kwaye kufuneka ijongane nothotho lweengxaki:
✔ Ingxaki yamandla ojongano kumphezulu. Xa i-GaN ikhula kwi-substrate ye-Si, umphezulu we-Si substrate uya kuqala ufakwe i-nitrided ukwenza umaleko we-amorphous silicon nitride ongabambisani ne-nucleation kunye nokukhula kwe-high-density GaN. Ukongeza, umphezulu weSi uya kuqala uqhagamshelane neGa, eya kuphazamisa umphezulu we-Si substrate. Kubushushu obuphezulu, ukubola komphezulu we-Si kuya kusasazeka kwi-GaN epitaxial layer ukwenza amabala amnyama e-silicon.
✔ I-lattice engaguqukiyo engatshintshiyo phakathi kwe-GaN kunye ne-Si inkulu (~ 17%), eya kukhokelela ekubunjweni kwe-high-density threading dislocations kunye nokunciphisa kakhulu umgangatho we-epitaxial layer;
✔ Xa kuthelekiswa ne-Si, i-GaN ine-coefficient yokwandiswa kwe-thermal enkulu (i-GaN ye-thermal yokwandisa i-coefficient malunga ne-5.6 × 10-6K-1, i-coefficient yokwandisa i-thermal malunga ne-2.6 × 10-6K-1), kwaye iintanda zinokuveliswa kwi-GaN i-epitaxial layer ngexesha lokupholisa ukushisa kwe-epitaxial kwiqondo lokushisa legumbi;
✔ I-Si isabela nge-NH3 kumaqondo obushushu aphezulu ukwenza i-polycrystalline SiNx. I-AlN ayinako ukwenza i-nucleus ejolise ngokukhethiweyo kwi-polycrystalline SiNx, ekhokelela kuqhelaniso olungalungelelananga lomaleko we-GaN owakhula kamva kunye nenani eliphezulu leziphene, okukhokelela kumgangatho ombi wekristale we-GaN epitaxial layer, kunye nobunzima bokwenza i-crystalline enye. I-GaN epitaxial layer [6].
Ukuze kulungiswe ingxaki ye-lattice enkulu engafaniyo, abaphandi baye bazama ukwazisa izinto ezifana ne-AlAs, i-GaAs, i-AlN, i-GaN, i-ZnO, kunye ne-SiC njenge-buffer layers kwi-Si substrates. Ukuze ugweme ukubunjwa kwe-polycrystalline SiNx kunye nokunciphisa imiphumo emibi kumgangatho we-crystal yezinto ze-GaN / AlN / Si (111), i-TMAl idla ngokufuneka ukuba ifakwe ixesha elithile ngaphambi kokukhula kwe-epitaxial ye-AlN buffer layer. ukuthintela i-NH3 ekubeni isabele ngomphezulu we-Si oveziweyo ukwenza i-SiNx. Ukongezelela, iteknoloji ye-epitaxial efana ne-pattered substrate technology ingasetyenziselwa ukuphucula umgangatho we-epitaxial layer. Ukuphuhliswa kobu buchwepheshe kunceda ukuvimbela ukubunjwa kwe-SiNx kwi-interface ye-epitaxial, ukukhuthaza ukukhula kwe-dimensional ye-GaN epitaxial layer, kunye nokuphucula umgangatho wokukhula kwe-epitaxial layer. Ukongeza, i-AlN buffer layer iyaziswa ukuhlawulela uxinzelelo olubangelwa ngumahluko kwi-coefficients yokwandiswa kwe-thermal ukuphepha ukuqhekeka kwi-GaN epitaxial layer kwi-silicon substrate. Uphando lukaKrost lubonisa ukuba kukho ulungelelwaniso oluhle phakathi kobunzima be-AlN buffer layer kunye nokuncipha koxinzelelo. Xa ubukhulu be-buffer layer bufikelela kwi-12nm, i-epitaxial layer thicker than 6μm ingakhuliswa kwi-silicon substrate ngokusebenzisa iskimu sokukhula esifanelekileyo ngaphandle kwe-epitaxial layer cracking.
Emva kwemizamo yexesha elide yabaphandi, umgangatho we-GaN epitaxial layers ekhulile kwi-silicon substrates iye yaphuculwa kakhulu, kwaye izixhobo ezifana ne-field effect transistors, i-Schottky barrier ultraviolet detectors, ii-LED eziluhlaza okwesibhakabhaka kunye ne-ultraviolet lasers zenze inkqubela phambili enkulu.
Isishwankathelo, kuba ii-substrates ze-GaN epitaxial ezisetyenziswa ngokuqhelekileyo ziyi-heterogeneous epitaxy, zonke zijongene neengxaki eziqhelekileyo ezifana nokungafani kwe-lattice kunye nomahluko omkhulu kwi-coefficients yokwandisa i-thermal ukuya kumaqondo ahlukeneyo. I-Homogeneous epitaxial substrates ye-GaN ye-GaN ilinganiselwe ngokukhula kobuchwepheshe, kwaye i-substrates ayikaveliswa ngobuninzi. Iindleko zemveliso ziphezulu, ubukhulu be-substrate buncinci, kwaye umgangatho we-substrate awufanelekanga. Ukuphuhliswa kwe-GaN epitaxial substrates ezintsha kunye nokuphuculwa komgangatho we-epitaxial kuseyenye yezinto ezibalulekileyo ezithintela uphuhliso oluqhubekayo lwe-GaN epitaxial industry.
IV. Iindlela eziqhelekileyo ze-GaN epitaxy
I-MOCVD (ikhemikhali yokubeka umphunga)
Kubonakala ngathi i-epitaxy ye-homogeneous kwi-substrates ye-GaN lolona khetho lulungileyo lwe-GaN epitaxy. Nangona kunjalo, ekubeni i-precursors ye-chemical vapor deposition yi-trimethylgallium kunye ne-ammonia, kunye negesi ethwala i-hydrogen, iqondo lokushisa eliqhelekileyo lokukhula kwe-MOCVD li malunga ne-1000-1100℃, kwaye izinga lokukhula kwe-MOCVD limalunga nee-microns ezimbalwa ngeyure. Inokuvelisa ujongano oluphezulu kwinqanaba leathom, efanelekileyo kakhulu ekukhuleni kwe-heterojunctions, imithombo ye-quantum, i-superlattices kunye nezinye izakhiwo. Isantya sokukhula kwayo ngokukhawuleza, ukufana okuhle, kunye nokufaneleka kwendawo enkulu kunye nokukhula kwamacandelo amaninzi ahlala esetyenziswa kwimveliso yemizi-mveliso.
MBE (i-molecular beam epitaxy)
Kwi-molecular beam epitaxy, i-Ga isebenzisa umthombo we-elemental, kunye ne-nitrogen esebenzayo ifumaneka kwi-nitrogen nge-plasma ye-RF. Xa kuthelekiswa nendlela ye-MOCVD, iqondo lobushushu le-MBE limalunga ne-350-400℃ esezantsi. Ubushushu bokukhula obusezantsi bunokunqanda ungcoliseko oluthile olunokuthi lubangelwe ziimekobume zobushushu obuphezulu. Inkqubo ye-MBE isebenza phantsi kwe-ultra-high vacuum, evumela ukuba idibanise iindlela ezininzi zokubona kwi-situ. Kwangaxeshanye, izinga lokukhula kwayo kunye namandla emveliso ayinakuthelekiswa ne-MOCVD, kwaye isetyenziswa kakhulu kuphando lwezenzululwazi [7].
Umfanekiso 5 (a) Eiko-MBE schematic (b) MBE main reaction chamber schematic
Indlela ye-HVPE (i-hydride vapor phase epitaxy)
Izandulela zendlela ye-hydride vapor phase epitaxy yi-GaCl3 kunye ne-NH3. Detchprohm et al. isebenzise le ndlela yokukhulisa i-GaN epitaxial layer ngamakhulu eemicrons ubukhulu kumphezulu wesapphire substrate. Kuvavanyo lwabo, umaleko we-ZnO wakhuliswa phakathi kwe-sapphire substrate kunye ne-epitaxial layer njenge-buffer layer, kwaye i-epitaxial layer yahluthwa ukusuka kumphezulu we-substrate. Xa kuthelekiswa ne-MOCVD kunye ne-MBE, olona phawu luphambili lwendlela ye-HVPE lizinga eliphezulu lokukhula, elilungele ukuveliswa kweemaleko ezishinyeneyo kunye nemathiriyeli eninzi. Nangona kunjalo, xa ubukhulu be-epitaxial layer budlula i-20μm, i-epitaxial layer eveliswa yile ndlela ixhomekeke ekuqhekekeni.
I-Akira USUI yazisa iteknoloji yesubstrate enepateni esekwe kule ndlela. Baqale bakhula i-1-1.5μm ebhityileyo ye-GaN epitaxial layer kwi-sapphire substrate besebenzisa indlela ye-MOCVD. I-epitaxial layer iquka i-20nm engqingqwa ye-GaN buffer layer ekhule phantsi kweemeko zobushushu obuphantsi kunye ne-GaN layer ekhule phantsi kweemeko eziphezulu zobushushu. Emva koko, kwi-430 ℃, umaleko we-SiO2 ubekwe phezu komgangatho we-epitaxial layer, kwaye imivimbo yeefestile yenziwa kwifilimu ye-SiO2 nge-photolithography. Isithuba semigca sasiyi-7μm kwaye ububanzi bemaski busuka kwi-1μm ukuya kwi-4μm. Emva kolu phuculo, bafumana i-GaN epitaxial layer kwi-2-intshi ye-diameter yesafire substrate eyayingena-crack-free kwaye igudileyo njengesibuko naxa ubukhulu benyuka ukuya kumashumi okanye kumakhulu ama-microns. Ukuxinana kwesiphene kwancitshiswa ukusuka kwi-109-1010cm-2 yendlela ye-HVPE yendabuko malunga ne-6 × 107cm-2. Baphinde babonisa kuvavanyo ukuba xa izinga lokukhula lidlula i-75μm / h, umgangatho wesampuli uya kuba rhabaxa [8].
Isazobe 6 soMzobo weSubstrate Schematic
V. Isishwankathelo kunye ne-Outlook
Izixhobo ze-GaN zaqala ukuvela ngo-2014 xa ukukhanya okuluhlaza kwe-LED kwaphumelela iBhaso leNobel kwiFiziksi ngaloo nyaka, kwaye kwangena kwibala loluntu lokutshaja ngokukhawuleza kwibala le-elektroniki yabathengi. Ngapha koko, usetyenziso kwizixhobo zokukhulisa amandla kunye nezixhobo zeRF ezisetyenziswa kwizikhululo ezisisiseko ze-5G abantu abaninzi abangaziboniyo ziye zavela ngokuzolileyo. Kwiminyaka yakutshanje, ukuphumelela kwezixhobo zeGaN ezisekwe kwibakala lemoto kulindeleke ukuba kuvule iindawo ezintsha zokukhula kwimakethi yesicelo sezinto zeGaN.
Imfuno enkulu yemarike ngokuqinisekileyo iya kukhuthaza uphuhliso lwamashishini anxulumene ne-GaN kunye nobuchwepheshe. Ngokukhula kunye nokuphuculwa kwe-industrial chain chain enxulumene ne-GaN, iingxaki ezijongene nobuchwepheshe be-GaN epitaxial technology ekugqibeleni ziya kuphuculwa okanye zoyiswe. Kwixesha elizayo, abantu ngokuqinisekileyo baya kuphuhlisa ngakumbi itekhnoloji entsha ye-epitaxial kunye nokukhethwa kwe-substrate ebalaseleyo. Ngelo xesha, abantu baya kuba nako ukukhetha eyona ifanelekileyo iteknoloji yophando lwangaphandle kunye ne-substrate yeemeko ezahlukeneyo zesicelo ngokweempawu zeemeko zesicelo, kwaye zivelise iimveliso ezikhuphisanayo ezilungiselelweyo.
Ixesha lokuposa: Jun-28-2024