Ukwethulwa Okuyisisekelo Kwenqubo Yokukhula Kwe-SiC Epitaxial

I-Epitaxial layer ifilimu ethize yekristalu eyodwa ekhule ku-wafer ngenqubo ye-ep ·itaxial, futhi i-substrate wafer nefilimu ye-epitaxial kuthiwa yi-epitaxial wafer.Ngokukhulisa ungqimba lwe-silicon carbide epitaxial ku-conductive silicon carbide substrate, i-silicon carbide homogeneous epitaxial wafer ingabuye ilungiswe ibe yi-Schottky diodes, MOSFETs, IGBTs namanye amadivaysi kagesi, phakathi kwawo i-4H-SiC substrate isetshenziswa kakhulu.

Ngenxa yenqubo ehlukene yokukhiqiza ye-silicon carbide idivayisi yamandla kanye nedivayisi yamandla ye-silicon yendabuko, ayikwazi ukwakhiwa ngokuqondile ku-silicon carbide single crystal material.Izinto ezengeziwe zekhwalithi ephezulu ze-epitaxial kufanele zikhuliswe ku-conductive single crystal substrate, futhi amadivaysi ahlukahlukene kufanele enziwe kungqimba lwe-epitaxial.Ngakho-ke, ikhwalithi ye-epitaxial layer inethonya elikhulu ekusebenzeni kwedivayisi.Ukuthuthukiswa kokusebenza kwemishini yamandla ehlukene futhi kubeka phambili izidingo eziphakeme zogqinsi lwe-epitaxial layer, ukugxiliswa kwe-doping kanye nokukhubazeka.

I-FIG.1. Ubudlelwano phakathi kokugxila kwe-doping kanye nogqinsi lwe-epitaxial yedivayisi ye-unipolar kanye ne-voltage evimbayo

Izindlela zokulungiselela ze-SIC epitaxial layer ikakhulukazi zifaka indlela yokukhula yokuhwamuka, ukukhula kwe-epitaxial yesigaba se-liquid (LPE), ukukhula kwe-molecular beam epitaxial growth (MBE) kanye ne-chemical vapor deposition (CVD).Njengamanje, i-chemical vapor deposition (CVD) iyindlela eyinhloko esetshenziselwa ukukhiqizwa okukhulu ezimbonini.

I-FIG.2. Ukuqhathaniswa kwezindlela zokulungiselela eziyinhloko ze-epitaxial layer

Ku-off-axis {0001} ene-engeli etshekile ethile, njengoba kukhonjisiwe kuMfanekiso 2(b), ukuminyana kwendawo yesitebhisi kukhudlwana, futhi usayizi wendawo yesinyathelo mncane, futhi i-crystal nucleation akulula ukuyenza. zenzeka endaweni yesinyathelo, kodwa kaningi kwenzeka endaweni yokuhlangana yesinyathelo.Kulokhu, kunokhiye owodwa kuphela we-nucleating.Ngakho-ke, ungqimba lwe-epitaxial lungakwazi ukuphindaphinda kahle ukuhleleka kokunqwabelanisa kwe-substrate, ngaleyo ndlela kususe inkinga yokuhlalisana kwezinhlobo eziningi.

I-FIG.3. Umdwebo wenqubo ebonakalayo ye-4H-SiC yokulawula isinyathelo se-epitaxy indlela

I-FIG.4. Izimo ezibucayi zokukhula kwe-CVD nge-4H-SiC indlela ye-epitaxy elawulwa isinyathelo

I-FIG.5. Ukuqhathaniswa kwamazinga okukhula ngaphansi kwemithombo ehlukene ye-silicon ku-4H-SiC epitaxy

Njengamanje, ubuchwepheshe be-silicon carbide epitaxy sebuvuthiwe kuma-voltage aphansi naphakathi (njengamadivayisi angu-1200 volt).Ukufana kogqinsi, ukugxilwa kwe-doping ukufana nokusabalaliswa kwesici kongqimba lwe-epitaxial kungafinyelela ezingeni elihle uma kuqhathaniswa, elingahlangabezana nezidingo ze-voltage ephakathi nendawo nephansi ye-SBD (Schottky diode), i-MOS (i-metal oxide semiconductor field effect transistor), i-JBS ( i-junction diode) namanye amadivaysi.

Kodwa-ke, emkhakheni wengcindezi ephezulu, ama-epitaxial wafers asadinga ukunqoba izinselelo eziningi.Isibonelo, kumadivayisi adinga ukumelana nama-volts angu-10,000, ukujiya kongqimba lwe-epitaxial kumele kube ngu-100μm.Uma kuqhathaniswa namadivayisi ane-voltage ephansi, ukujiya kwesendlalelo se-epitaxial kanye nokufana kokugxiliswa kwe-doping kuhluke kakhulu, ikakhulukazi ukufana kokuhlushwa kwe-doping.Ngesikhathi esifanayo, iphutha likanxantathu kungqimba lwe-epitaxial lizophinde libhubhise ukusebenza okuphelele kwedivayisi.Kuzinhlelo zokusebenza ezinamandla amakhulu, izinhlobo zedivayisi zivamise ukusebenzisa amadivaysi e-bipolar, adinga impilo encane ephezulu kungqimba lwe-epitaxial, ngakho-ke inqubo idinga ukuthuthukiswa ukuze kuthuthukiswe impilo yabantu abambalwa.

Njengamanje, i-epitaxy yasekhaya ngokuyinhloko ingamayintshi angu-4 no-6 amayintshi, futhi ingxenye ye-silicon carbide epitaxy yosayizi omkhulu iyanda unyaka nonyaka.Usayizi weshidi le-silicon carbide epitaxial ikakhulukazi unqunyelwe usayizi we-silicon carbide substrate.Njengamanje, i-6-inch silicon carbide substrate isidayiswe, ngakho-ke i-silicon carbide epitaxial ishintsha kancane kancane isuka kuma-intshi angu-4 kuya ku-6 amayintshi.Ngokuthuthuka okuqhubekayo kobuchwepheshe bokulungiselela i-silicon carbide substrate kanye nokwanda komthamo, intengo ye-silicon carbide substrate iyehla kancane kancane.Ekwakhiweni kwentengo yeshidi le-epitaxial, i-substrate ilandisa ngaphezu kuka-50% wezindleko, ngakho-ke ngokuncipha kwenani le-substrate, intengo ye-silicon carbide epitaxial sheet nayo kulindeleke ukuthi yehle.