I-Silicon Carbide Epitaxy: Izimiso Zenqubo, Ukulawula Ubukhulu, kanye Nezinselele Zokukhubazeka

I-epitaxy ye-silicon carbide (SiC) isenhliziyweni yenguquko yamandla kagesi yesimanje. Kusukela ezimotweni zikagesi kuya ezinhlelweni zamandla avuselelekayo kanye nokushayela kwezimboni okunamandla aphezulu, ukusebenza kanye nokuthembeka kwamadivayisi e-SiC kuncike kancane ekwakhiweni kwesekethe kunalokho okwenzekayo ngesikhathi sokukhula kwekristalu okumbalwa ebusweni be-wafer. Ngokungafani ne-silicon, lapho i-epitaxy kuyinqubo evuthiwe nethethelelayo, i-epitaxy ye-SiC iwumsebenzi oqondile nongathetheleli ekulawuleni isikali se-athomu.

Lesi sihloko sihlola ukuthi kanjaniI-SiC epitaxyisebenza kahle, kungani ukulawulwa kobukhulu kubaluleke kangaka, nokuthi kungani amaphutha ehlala eyinye yezinselelo ezinzima kakhulu kulo lonke uchungechunge lokuhlinzekwa kwe-SiC.

1. Kuyini i-SiC Epitaxy Futhi Kungani Kubalulekile?

I-Epitaxy ibhekisela ekukhuleni kwesendlalelo sekristalu esinelungiselelo le-athomu elilandela elo le-substrate engaphansi. Kumadivayisi wamandla e-SiC, le sendlalelo se-epitaxial sakha indawo esebenzayo lapho kuchazwa khona ukuvimba kwe-voltage, ukuqhuba kwamanje, kanye nokuziphatha kokushintsha.

Ngokungafani namadivayisi e-silicon, avame ukuthembela ekusetshenzisweni kwe-bulk doping, amadivayisi e-SiC ancike kakhulu ezingqimbeni ze-epitaxial ezinobukhulu obuklanywe ngokucophelela kanye namaphrofayili e-doping. Umehluko we-micrometer eyodwa kuphela ekuqineni kwe-epitaxial ungashintsha kakhulu i-voltage yokuqhekeka, ukumelana nokumelana, kanye nokuthembeka kwesikhathi eside.

Ngamafuphi, i-SiC epitaxy akuyona inqubo esekelayo—ichaza idivayisi.

2. Izisekelo Zokukhula Kwe-SiC Epitaxial

Iningi le-epitaxy ye-SiC yezentengiselwano lenziwa kusetshenziswa i-chemical vapor deposition (CVD) emazingeni okushisa aphezulu kakhulu, ngokuvamile phakathi kuka-1,500 °C no-1,650 °C. Amagesi e-Silane nama-hydrocarbon afakwa ku-reactor, lapho ama-athomu e-silicon ne-carbon ebola khona futhi aphinde ahlangane phezu kobuso be-wafer.

Kunezici eziningana ezenza i-SiC epitaxy ibe yinkimbinkimbi kakhulu kune-silicon epitaxy:

• Ukubopha okuqinile kwe-covalent phakathi kwe-silicon ne-carbon

• Amazinga okushisa aphezulu okukhula asondele kakhulu emikhawulweni yokuzinza kwezinto ezibonakalayo

• Ukuzwela ezinyathelweni zangaphezulu kanye nokusikwa kabi kwe-substrate

• Ukuba khona kwama-polytype amaningi e-SiC

Ngisho nokuphambuka okuncane ekugelezeni kwegesi, ukufana kwezinga lokushisa, noma ukulungiswa kwendawo kungaletha amaphutha asakazeka ngesendlalelo se-epitaxial.

3. Ukulawula Ubukhulu: Kungani Ama-Micrometer Ebalulekile

Kumadivayisi kagesi e-SiC, ukujiya kwe-epitaxial kunquma ngqo amandla kagesi. Isibonelo, idivayisi engu-1,200 V ingadinga ungqimba lwe-epitaxial olunobukhulu obungama-micrometer ambalwa kuphela, kuyilapho idivayisi engu-10 kV ingadinga amashumi ama-micrometer.

Ukufinyelela ubukhulu obufanayo kuyo yonke i-wafer engu-150 mm noma engu-200 mm kuyinselele enkulu yobunjiniyela. Izinguquko ezincane njenge-±3% zingaholela ku:

• Ukusatshalaliswa kwensimu kagesi okungalingani

• Imingcele ye-voltage encishisiwe yokuqhekeka

• Ukungahambisani kokusebenza kwedivayisi nedivayisi

Ukulawula ukujiya kuyinkimbinkimbi kakhulu ngesidingo sokuhlushwa okuqondile kwe-doping. Ku-SiC epitaxy, ukujiya kanye ne-doping kuhlangene kakhulu—ukulungisa okukodwa kuvame ukuthinta okunye. Lokhu kuncika kuphoqa abakhiqizi ukuthi balinganisele izinga lokukhula, ukufana, kanye nekhwalithi yezinto ezibonakalayo ngasikhathi sinye.

4. Amaphutha: Inselele Eqhubekayo

Naphezu kwentuthuko esheshayo embonini, amaphutha ahlala eyisithiyo esiyinhloko ku-SiC epitaxy. Ezinye zezinhlobo zamaphutha ezibaluleke kakhulu zifaka:

• Ukuhlukaniswa kwendiza eyisisekelo, okungakhula ngesikhathi sokusebenza kwedivayisi futhi kubangele ukuwohloka kwe-bipolar

• Amaphutha okubeka izinto ndawonye, okuvame ukubangelwa ngesikhathi sokukhula kwe-epitaxial

• Amapayipi Amancane, encishisiwe kakhulu ezindaweni zesimanje kodwa isanomthelela ekuvuneni

• Amaphutha kakaroti kanye namaphutha angunxantathu, okuhlobene nokukhubazeka kokukhula kwendawo

Okwenza amaphutha e-epitaxial abe yinkinga kakhulu ukuthi amaningi avela ku-substrate kodwa ayashintsha ngesikhathi sokukhula. I-wafer ebonakala ivumelekile ingaba namaphutha asebenza ngogesi kuphela ngemva kwe-epitaxy, okwenza ukuhlolwa kusenesikhathi kube nzima.

5. Indima Yekhwalithi Ye-Substrate

I-Epitaxy ayikwazi ukuvala izikhala ezingezinhle. Ubulukhuni bomphezulu, i-angle engacaci kahle, kanye nobuningi bokuhlukana kwendiza eyisisekelo konke kuthonya kakhulu imiphumela ye-epitaxial.

Njengoba ububanzi be-wafer bukhula kusuka ku-150 mm kuya ku-200 mm nangaphezulu, ukugcina ikhwalithi ye-substrate efanayo kuba nzima. Ngisho nokushintshashintsha okuncane kulo lonke i-wafer kungahumusha kube umehluko omkhulu ekuziphatheni kwe-epitaxial, kwandise ubunzima benqubo futhi kunciphise isivuno sonke.

Lokhu kuhlangana okuqinile phakathi kwe-substrate ne-epitaxy kungenye yezizathu ezenza ukuthi uchungechunge lokuhlinzekwa kwe-SiC luhlanganiswe ngokuqonde kakhulu kunomlingani walo we-silicon.

6. Izinselele Zokukhulisa Usayizi We-Wafer Omkhulu

Ukushintshela kuma-wafer amakhulu e-SiC kwandisa yonke inselelo ye-epitaxial. Ama-gradient okushisa aba nzima ukuwalawula, ukufana kokugeleza kwegesi kuba bucayi kakhulu, futhi izindlela zokusabalala kwamaphutha ziyanda.

Ngesikhathi esifanayo, abakhiqizi bamadivayisi kagesi bafuna imininingwane eqinile: izilinganiso eziphezulu ze-voltage, ubuningi obuphansi besici, kanye nokuvumelana okungcono kwe-wafer kuya ku-wafer. Ngakho-ke izinhlelo ze-Epitaxy kumele zifinyelele ukulawula okungcono ngenkathi zisebenza ngezikali ezingakaze zicatshangelwe ekuqaleni ze-SiC.

Lokhu kungezwani kuchaza okuningi kokusungula izinto ezintsha kwanamuhla ekwakhiweni kwe-epitaxial reactor kanye nokwenza ngcono inqubo.

7. Kungani i-SiC Epitaxy Ichaza Umnotho Wedivayisi

Ekukhiqizweni kwe-silicon, i-epitaxy ivame ukuba yinto ebiza kakhulu. Ekukhiqizweni kwe-SiC, iyisishayeli senani.

I-Epitaxial yield inquma ngqo ukuthi zingaki izingcezu ze-wafer ezingangena ekwakhiweni kwedivayisi, nokuthi zingaki izingcezu eziqediwe ezihlangabezana nencazelo. Ukuncipha okuncane kobuningi besici noma ukuhlukahluka kobukhulu kungaholela ekunciphiseni okukhulu kwezindleko ezingeni lesistimu.

Yingakho intuthuko ku-SiC epitaxy ivame ukuba nomthelela omkhulu ekwamukelweni kwemakethe kunentuthuko ekwakhiweni kwamadivayisi uqobo.

8. Ukubheka Phambili

I-SiC epitaxy ishintsha kancane kancane isuka ebucikweni iye kwisayensi, kodwa ayikafiki ekuvuthweni kwe-silicon. Intuthuko eqhubekayo izoncika ekuqapheni okungcono kwangaphakathi, ekulawulweni okuqinile kwe-substrate, kanye nokuqonda okujulile kwezindlela zokwakheka kwamaphutha.

Njengoba amandla kagesi eqhubekela phambili ekufinyeleleni kuma-voltage aphezulu, amazinga okushisa aphezulu, kanye nezindinganiso zokuthembeka eziphakeme, i-epitaxy izohlala iyinqubo ethule kodwa enqumayo yokwakha ikusasa lobuchwepheshe be-SiC.

Ekugcineni, ukusebenza kwezinhlelo zamandla zesizukulwane esilandelayo kungase kunqunywe hhayi ngemidwebo yesekethe noma izinto ezintsha zokupakisha, kodwa ngendlela ama-athomu abekwe ngayo ngokunembile—ungqimba olulodwa lwe-epitaxial ngesikhathi.