ʻO ka hoʻolauna kumu o ka SiC Epitaxial Growth Process

ʻO ka papa epitaxial kahi kiʻi aniani kikoʻī i ulu ʻia ma ka wafer e ka ep·itaxial process, a ua kapa ʻia ka wafer substrate a me ka kiʻi epitaxial epitaxial wafer. Ma ka ulu ʻana i ka papa epitaxial silicon carbide ma ka substrate silicon carbide conductive, hiki ke hoʻomākaukau hou ʻia ka wafer epitaxial homogeneous silicon carbide i nā diodes Schottky, MOSFET, IGBT a me nā mea mana ʻē aʻe, ma waena o ka 4H-SiC substrate ka mea maʻamau.

Ma muli o ke kaʻina hana ʻokoʻa o ka mea mana silicon carbide a me ka mīkini mana silicon kuʻuna, ʻaʻole hiki ke hana pololei ʻia ma luna o nā mea aniani hoʻokahi. Pono e hoʻoulu ʻia nā mea epitaxial kiʻekiʻe kiʻekiʻe ma luna o ka substrate kristal hoʻokahi conductive, a pono e hana ʻia nā mea like ʻole ma ka papa epitaxial. No laila, ʻo ka maikaʻi o ka papa epitaxial ka mana nui i ka hana o ka hāmeʻa. ʻO ka hoʻomaikaʻi ʻana i ka hana o nā mana mana like ʻole e kau i mua i nā koi kiʻekiʻe no ka mānoanoa o ka papa epitaxial, doping concentration a me nā hemahema.

FIG. 1. ʻO ka pilina ma waena o ka neʻe ʻana o ka doping a me ka mānoanoa o ka papa epitaxial o ka mea unipolar a me ka pale uila.

ʻO nā ʻano hoʻomākaukau o ka SIC epitaxial layer ka mea nui e pili ana i ke ʻano o ka ulu ʻana o ka evaporation, ka ulu ʻana o ka epitaxial phase wai (LPE), ka ulu ʻana o ka epitaxial molecular beam (MBE) a me ka hoʻoheheʻe ʻana o ka chemical (CVD). I kēia manawa, ʻo ka chemical vapor deposition (CVD) ke ala nui i hoʻohana ʻia no ka hana nui ʻana i nā hale hana.

FIG. 2. Hoʻohālikelike i nā ʻano hoʻomākaukau nui o ka papa epitaxial

Ma ka ʻaoʻao ʻaoʻao ʻē aʻe {0001} me kahi kihi hiʻi, e like me ka mea i hōʻike ʻia ma ke Kiʻi 2(b), ʻoi aku ka nui o ka ʻili o ka ʻanuʻu, a ʻoi aku ka liʻiliʻi o ka nui o ka ʻili, a ʻaʻole maʻalahi ka nucleation kristal. aia ma ka ʻanuʻu ʻanuʻu, akā ʻoi aku ka nui o ka loaʻa ʻana ma ka wahi hoʻohui o ka ʻanuʻu. I kēia hihia, hoʻokahi wale nō kī nucleating. No laila, hiki i ka papa epitaxial ke hoʻopili pono i ka hoʻonohonoho hoʻonohonoho o ka substrate, no laila e hoʻopau i ka pilikia o ka noho like ʻana o nā ʻano like ʻole.

FIG. 3. Kiʻikuhi kaʻina hana kino o 4H-SiC step control epitaxy method

FIG. 4. Nā kūlana koʻikoʻi no ka ulu ʻana o CVD e 4H-SiC step-controlled epitaxy method

FIG. 5. Hoʻohālikelike i ka ulu ʻana ma lalo o nā kumu silika like ʻole ma 4H-SiC epitaxy

I kēia manawa, ʻano oʻo loa ka ʻenehana silicon carbide epitaxy i nā noi uila haʻahaʻa a me waena (e like me nā mea 1200 volt). ʻO ke kūlike o ka mānoanoa, ka like ʻole o ka doping a me ka hāʻawi ʻana i nā hemahema o ka papa epitaxial hiki ke hiki i kahi pae maikaʻi, hiki ke hoʻokō pono i nā pono o ka waena a me ka haʻahaʻa haʻahaʻa SBD (Schottky diode), MOS (metal oxide semiconductor field effect transistor), JBS ( junction diode) a me nā mea hana ʻē aʻe.

Eia nō naʻe, ma ke kahua o ke kaomi kiʻekiʻe, pono nā wafers epitaxial e lanakila i nā pilikia he nui. No ka laʻana, no nā mea pono e kū i ka 10,000 volts, pono ka mānoanoa o ka papa epitaxial ma kahi o 100μm. Ke hoʻohālikelike ʻia me nā hāmeʻa haʻahaʻa haʻahaʻa, ʻokoʻa ka mānoanoa o ka papa epitaxial a me ka like ʻole o ka hoʻopaʻa ʻana o ka doping, ʻoi aku ka like o ka hoʻohālikelike ʻana o ka ʻike doping. I ka manawa like, e hoʻopau ka hemahema triangle i ka papa epitaxial i ka hana holoʻokoʻa o ka hāmeʻa. I nā noi kiʻekiʻe-voltage, hoʻohana nā ʻano mea hana i nā mea bipolar, e koi ana i kahi ola liʻiliʻi kiʻekiʻe i ka papa epitaxial, no laila pono e hoʻomaikaʻi ʻia ke kaʻina hana e hoʻomaikaʻi ai i ke ola liʻiliʻi.

I kēia manawa, ʻo ka nui o ka epitaxy home he 4 iniha a me 6 iniha, a ke piʻi nei ka nui o ka nui o ka silicon carbide epitaxy i kēlā me kēia makahiki. ʻO ka nui o ka silicon carbide epitaxial sheet i kaupalena ʻia e ka nui o ka substrate silicon carbide. I kēia manawa, ua kūʻai kūʻai ʻia ka substrate silicon carbide 6-inch, no laila ke neʻe mālie nei ka silicon carbide epitaxial mai 4 iniha a 6 iniha. Me ka hoʻomau mau ʻana o ka ʻenehana hoʻomākaukau ʻana i ka silicon carbide substrate a me ka hoʻonui ʻana i ka hiki, ke emi mālie nei ke kumukūʻai o ka substrate silicon carbide. I ka hoʻokumu ʻana o ke kumukūʻai epitaxial sheet, ʻoi aku ka nui o ka substrate ma mua o 50% o ke kumukūʻai, no laila me ka emi ʻana o ke kumukūʻai substrate, ua manaʻo ʻia e emi iho ke kumukūʻai o ka pepa silicon carbide epitaxial.