I-CVD ye-silicon carbide yokwambathisa-2

I-CVD ye-silicon carbide yokugquma

1. Kutheni kukho ai-silicon carbide yokugquma

I-epitaxial layer yifilimu eyodwa yekristale encinci ekhule ngokwesiseko se-wafer ngokusebenzisa inkqubo ye-epitaxial. I-substrate wafer kunye nefilimu ebhityileyo ye-epitaxial ngokudibeneyo ibizwa ngokuba yi-epitaxial wafers. Phakathi kwabo, ii-silicon carbide epitaxialumaleko ukhuliswe kwi-silicon carbide substrate eqhubayo ukufumana i-silicon carbide homogeneous epitaxial wafer, enokuthi yenziwe ngakumbi ibe zizixhobo zamandla ezifana ne-Schottky diodes, MOSFETs, kunye nee-IGBTs. Phakathi kwazo, eyona nto isetyenziswa kakhulu yi-4H-SiC substrate.

Ekubeni zonke izixhobo zisebenza ngokusisiseko kwi-epitaxy, umgangatho wei-epitaxyinempembelelo enkulu ekusebenzeni kwesixhobo, kodwa umgangatho we-epitaxy uchaphazeleka ngokusetyenzwa kweekristale kunye ne-substrates. Iphakathi kweshishini kwaye idlala indima ebaluleke kakhulu kuphuhliso lweshishini.

Iindlela eziphambili zokulungiselela i-silicon carbide epitaxial layers zezi: indlela yokukhula evaporation; i-liquid phase epitaxy (LPE); i-molecular beam epitaxy (MBE); Ukufakwa komphunga kwikhemikhali (CVD).

Phakathi kwabo, i-chemical vapor deposition (CVD) yeyona ndlela idumileyo ye-4H-SiC homoepitaxial. I-4-H-SiC-CVD epitaxy ngokuqhelekileyo isebenzisa izixhobo ze-CVD, ezinokuqinisekisa ukuqhubeka kwe-epitaxial layer 4H crystal SiC phantsi kweemeko eziphezulu zokushisa.

Kwizixhobo ze-CVD, i-substrate ayinakubekwa ngokuthe ngqo kwintsimbi okanye ibekwe nje kwisiseko se-epitaxial deposition, kuba ibandakanya izinto ezahlukeneyo ezifana nolwalathiso lokuhamba kwegesi (i-horizontal, vertical), ukushisa, uxinzelelo, ukulungiswa, kunye nokungcola okuwayo. Ngoko ke, isiseko siyafuneka, kwaye ke i-substrate ifakwe kwidiski, kwaye i-epitaxial deposition yenziwa kwi-substrate usebenzisa iteknoloji ye-CVD. Esi siseko sisiseko segraphite esigqunywe yiSiC.

Njengenxalenye engundoqo, isiseko segraphite sineempawu zamandla athile aphezulu kunye nemodyuli ethile, ukuxhathisa ukothuka okuhle kwe-thermal kunye nokumelana nokubola, kodwa ngexesha lenkqubo yokuvelisa, igraphite iya kugqwala kwaye ibe ngumgubo ngenxa yokushiyeka kweegesi ezidliwayo kunye nentsimbi ye-organic. umcimbi, kwaye ubomi benkonzo yesiseko segraphite buya kuncitshiswa kakhulu.

Ngelo xesha, i-graphite powder ewileyo iya kungcolisa i-chip. Kwinkqubo yokuvelisa i-silicon carbide epitaxial wafers, kunzima ukuhlangabezana neemfuno ezingqongqo zabantu zokusetyenziswa kwemathiriyeli yegraphite, ethi ithintele ngokunzulu uphuhliso nokusetyenziswa kwayo okusebenzayo. Ke ngoko, itekhnoloji yokwaleka yaqala ukunyuka.

2. Izinto ezilungileyo zeUkwaleka kweSiC

Iimpawu ezibonakalayo kunye neekhemikhali zokugquma zineemfuno eziqinileyo zokumelana nokushisa okuphezulu kunye nokumelana nokubola, okuchaphazela ngokuthe ngqo isivuno kunye nobomi bemveliso. Izinto ze-SiC zinamandla amakhulu, ubunzima obuphezulu, i-coefficient yokwandisa i-thermal ephantsi kunye nokuhanjiswa kakuhle kwe-thermal. Yinto ebalulekileyo yesakhiwo se-high-temperature kunye ne-high-temperature semiconductor material. Isetyenziswe kwisiseko segraphite. Izibonelelo zayo zezi:

-I-SiC i-corrosion-resistant kwaye inokusonga ngokupheleleyo isiseko segraphite, kwaye inoxinaniso oluhle lokuphepha ukonakaliswa yigesi eyingozi.

-I-SiC ine-conductivity ephezulu ye-thermal kunye namandla okubambisana okuphezulu kunye nesiseko segraphite, ukuqinisekisa ukuba ukugquma akulula ukuwa emva kwemijikelezo emininzi yokushisa kunye nokushisa okuphantsi.

-I-SiC inozinzo olufanelekileyo lweekhemikhali ukukhusela ukwambathisa ekungaphumeleli kwiqondo lokushisa eliphezulu kunye ne-corrosion atmosphere.

Ukongezelela, iifurnaces ze-epitaxial zezinto ezahlukeneyo zifuna iitreyi zegraphite ezinezalathi zokusebenza ezahlukeneyo. I-coefficient yokwandiswa kwe-thermal ehambelana nezixhobo zegraphite ifuna ukulungelelaniswa nobushushu bokukhula kwe-epitaxial furnace. Umzekelo, iqondo lobushushu le-silicon carbide epitaxial ukukhula liphezulu, kwaye itreyi enokwandiswa kwe-thermal coefficient ehambelana nayo iyafuneka. I-coefficient yokwandisa i-thermal ye-SiC isondele kakhulu kwi-graphite, eyenza ukuba ifaneleke njengento ekhethiweyo yokugubungela umphezulu wesiseko segraphite.
Izinto ze-SiC zineentlobo ezahlukeneyo zekristale, kwaye ezona ziqhelekileyo ziyi-3C, 4H kunye ne-6H. Iintlobo ezahlukeneyo zekristale zeSiC zinosetyenziso olwahlukileyo. Umzekelo, i-4H-SiC ingasetyenziselwa ukuvelisa izixhobo eziphezulu zamandla; I-6H-SiC yeyona nto izinzile kwaye ingasetyenziselwa ukwenza izixhobo ze-optoelectronic; I-3C-SiC ingasetyenziselwa ukuvelisa i-GaN epitaxial layers kunye nokuvelisa izixhobo ze-SiC-GaN RF ngenxa yesakhiwo esifana ne-GaN. I-3C-SiC ikwabizwa ngokuba yi-β-SiC. Ukusetyenziswa okubalulekileyo kwe-β-SiC kufana nefilimu encinci kunye nempahla yokugubungela. Ke ngoko, i-β-SiC okwangoku iyona nto iphambili yokwaleka.
Iingubo ze-SiC zisetyenziswa ngokuqhelekileyo kwimveliso ye-semiconductor. Zisetyenziswa ikakhulu kwi-substrates, i-epitaxy, i-oxidation diffusion, i-etching kunye nokufakelwa kwe-ion. Iimpawu ezibonakalayo kunye neekhemikhali zokugquma zineemfuno eziqinileyo ekuxhathiseni ukushisa okuphezulu kunye nokumelana nokubola, okuchaphazela ngokuthe ngqo isivuno kunye nobomi bemveliso. Ngoko ke, ukulungiswa kwe-coating ye-SiC kubalulekile.