Ukusetshenziswa kwezingxenye ze-graphite eziboshwe nge-TaC

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I-crucible, isibambi sembewu kanye nendandatho yomhlahlandlela ku-SiC kanye ne-AIN single crystal furnace kutshalwe ngendlela ye-PVT

Njengoba kuboniswe kuMfanekiso 2 [1], lapho indlela yokuthutha umhwamuko womzimba (PVT) isetshenziselwa ukulungisa i-SiC, ikristalu yembewu isendaweni enezinga lokushisa eliphansi, i-SiC eluhlaza isendaweni yokushisa ephezulu kakhulu (ngaphezu kuka-2400).℃), futhi impahla eluhlaza iyabola ukuze ikhiqize i-SiXCy (ikakhulukazi i-Si, SiC₂, Si₂C, njll.).Impahla yesigaba somhwamuko ithuthwa isuka endaweni yokushisa ephezulu iye kwikristalu yembewu endaweni yokushisa ephansi, fi-orming seed nuclei, ukukhula, nokukhiqiza amakristalu awodwa.Izinto zensimu ezishisayo ezisetshenziswa kule nqubo, njenge-crucible, indandatho yomhlahlandlela wokugeleza, isibambi sekristalu sembewu, kufanele imelane nezinga lokushisa eliphezulu futhi ngeke zingcolise izinto zokusetshenziswa ze-SiC kanye namakristalu e-SiC eyodwa.Ngokufanayo, izinto zokushisisa ekukhuleni kwekristalu eyodwa ye-AlN zidinga ukumelana ne-Al vapor, N.₂ukugqwala, futhi kudinga izinga lokushisa eliphakeme le-eutectic (nge AlN) ukuze unciphise isikhathi sokulungiselela ikristalu.

Kwatholakala ukuthi i-SiC[2-5] ne-AlN[2-3] ilungiswe nguI-TaC ehlanganisiwei-graphite thermal field materials were cleaner, cishe ingekho ikhabhoni (oxygen, nitrogen) nokunye ukungcola, amaphutha asemaphethelweni ambalwa, ukumelana okuncane esifundeni ngasinye, kanye nokuminyana kwe-micropore kanye nokushuba komgodi kwehliswe kakhulu (ngemuva kokumiswa kwe-KOH), kanye nekhwalithi yekristalu. yathuthukiswa kakhulu.Ngaphezu kwalokho,I-TaC crucibleizinga lokulahlekelwa kwesisindo licishe libe ngu-zero, ukubukeka akukonakali, kungenziwa kabusha (ukuphila kuze kufike ku-200h), kungathuthukisa ukusimama nokusebenza kahle kwalokhu kulungiselelwa kwekristalu eyodwa.

I-FIG.2. (a) Umdwebo ohleliwe wedivayisi ekhulayo ye-SiC crystal ingot ngendlela ye-PVT
(b) PhezuluI-TaC ehlanganisiweubakaki wembewu (kuhlanganise nembewu ye-SiC)
(c)Indandatho ye-graphite ehlanganiswe ne-TAC

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I-MOCVD GaN epitaxial layer ekhulayo heater

Njengoba kuboniswe kuMfanekiso 3 (a), ukukhula kwe-MOCVD GaN ubuchwepheshe bokufakwa komhwamuko wamakhemikhali obusebenzisa ukusabela kokubola kwe-organometrical ukuze kukhule amafilimu amancanyana ngokukhula kwe-vapor epitaxial.Ukunemba kwezinga lokushisa kanye nokufana kwe-cavity kwenza i-heater ibe ingxenye ebaluleke kakhulu yemishini ye-MOCVD.Ukuthi i-substrate ingashiswa ngokushesha nangokufanayo isikhathi eside (ngaphansi kokupholisa okuphindaphindiwe), ukuzinza ekushiseni okuphezulu (ukumelana nokugqwala kwegesi) kanye nokuhlanzeka kwefilimu kuzothinta ngqo ikhwalithi yokubekwa kwefilimu, ukuguquguquka kokuqina, kanye nokusebenza kwe-chip.

Ukuze kuthuthukiswe ukusebenza kahle kanye nokusetshenziswa kabusha kwe-heater ohlelweni lokukhula lwe-MOCVD GaN,I-TAC-coatedI-heater ye-graphite yethulwe ngempumelelo.Uma kuqhathaniswa ne-GaN epitaxial layer ekhuliswe isifudumezi esivamile (sisebenzisa i-pBN coating), ungqimba lwe-GaN epitaxial olukhuliswe isifudumezi se-TaC lucishe lufane nesakhiwo sekristalu, ukujiya okufanayo, amaphutha angaphakathi, idoping yokungcola kanye nokungcola.Ngaphezu kwalokho, i-I-TaC coatingine-resisivity ephansi kanye nokukhipha umoya ophansi, okungathuthukisa ukusebenza kahle nokufana kwe-heater, ngaleyo ndlela kunciphise ukusetshenziswa kwamandla nokulahlekelwa ukushisa.I-porosity ye-coating ingashintshwa ngokulawula imingcele yenqubo ukuze kuthuthukiswe izici zemisebe ye-heater futhi andise impilo yayo yesevisi [5].Lezi zinzuzo zenzaI-TaC ehlanganisiweama-heaters e-graphite ukukhetha okuhle kakhulu kwezinhlelo zokukhula ze-MOCVD GaN.

I-FIG.3. (a) Umdwebo wohlelo lwedivayisi ye-MOCVD yokukhula kwe-GaN epitaxial
(b) Isishicileli esibunjiwe se-graphite esihlanganiswe ne-TAC esifakwe ekusetheni kwe-MOCVD, singafaki isisekelo nobakaki (umfanekiso obonisa isisekelo nabakaki ekushisiseni)
(c) I-TAC-coated graphite heater ngemva kokukhula kwe-epitaxial ye-17 GaN.[6]

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I-susceptor eboshwe ye-epitaxy (i-wafer carrier)

Isithwali se-Wafer siyingxenye ebalulekile yesakhiwo sokulungiselela i-SiC, i-AlN, i-GaN namanye ama-wafer we-semiconductor wesigaba sesithathu kanye nokukhula kwe-epitaxial wafer.Iningi labathwali be-wafer lenziwe nge-graphite futhi limbozwe nge-SiC coating ukumelana nokugqwala okuvela kumagesi enqubo, ngebanga lokushisa le-epitaxial lika-1100 kuya ku-1600.°C, kanye nokumelana nokugqwala kwento evikelayo kudlala indima ebalulekile empilweni yesithwali esilucwecwana.Imiphumela ikhombisa ukuthi izinga lokugqwala le-TaC lihamba kancane ngokuphindwe ka-6 kune-SiC ekushiseni okuphezulu kwe-ammonia.Emazingeni okushisa aphezulu e-hydrogen, izinga lokugqwala lihamba kancane izikhathi ezingaphezu kweziyi-10 kune-SiC.

Kufakazelwe ngokuhlolwa ukuthi amathreyi ambozwe nge-TaC abonisa ukuhambisana okuhle kunqubo yesibani esiluhlaza okwesibhakabhaka se-GaN MOCVD futhi awakwethusi ukungcola.Ngemva kokulungiswa kwenqubo okulinganiselwe, amaledi akhule kusetshenziswa abathwali be-TaC abonisa ukusebenza okufanayo nokufana njengabathwali be-SiC abavamile.Ngakho-ke, impilo yesevisi yama-pallets ahlanganiswe ne-TAC ingcono kunaleyo ye-inki yamatshe angenalutho kanyeSiC cameraama-graphite pallets.