Dab tsi yog epitaxial wafer?

Epitaxy yog ib qho ntawm cov txheej txheem semiconductor. Hauv cov txheej txheem bipolar, txheej hauv qab ntawm silicon wafer yog P-hom substrate silicon (qee qhov ntxiv txheej faus); Tom qab ntawd ib txheej ntawm ib qho siv lead ua silicon yog cog rau ntawm substrate, uas yog hu ua epitaxial txheej; Tom qab ntawd, lub hauv paus cheeb tsam, cheeb tsam emitter, thiab lwm yam yog txhaj rau hauv txheej epitaxial. Thaum kawg, ib txoj kab ntsug NPN raj yog tsim los: cov txheej txheem epitaxial yog thaj chaw sau, thiab muaj cov cheeb tsam hauv paus thiab thaj chaw emitter ntawm txheej epitaxial. Epitaxial wafers yog silicon wafers nrog epitaxial txheej ntawm lub substrate. Vim tias qee lub chaw tsim khoom tsuas yog ua cov txheej txheem ntau lawm tom qab epitaxy, lawv yuav cov wafers epitaxial uas tau ua tiav los ntawm lwm tus rau cov txheej txheem tom ntej.
Khoom Taw Qhia
Semiconductor manufacturers feem ntau siv polished Si wafers (PW) thiab epitaxial Si wafers ua raw khoom rau ICs. Epitaxial wafers tau siv thaum xyoo 1980s. Lawv muaj qee yam khoom siv hluav taws xob uas tus qauv PW tsis muaj thiab tshem tawm ntau qhov chaw / ze-nto qhov chaw qhia thaum lub sij hawm siv lead ua loj hlob thiab tom qab wafer ua.
Keeb kwm, epitaxial wafers tau tsim los ntawm Si wafer manufacturers rau lawv tus kheej siv. Lawv tsis tau siv ntau hauv ICs. Lawv xav tau qhov kev tso tawm ntawm ib txheej ib leeg-crystal Si txheej rau saum npoo ntawm ib leeg-crystal Si wafer. Lub thickness ntawm lub epitaxial txheej feem ntau yog 2 mus rau 20 μm, thaum lub thickness ntawm lub substrate Si yog 610 μm (150 mm inch wafer) thiab 725 μm (200 mm wafer).
Epitaxial deposition tuaj yeem ua tiav ntau lub wafers ib zaug (ib txhij) lossis ib qho wafer. Ib leeg-wafer reactors tsim qhov zoo tshaj plaws zoo epitaxial txheej (zoo uniformity ntawm thickness thiab resistivity, thiab ob peb yam tsis xws luag); xws li epitaxial wafers yog siv nyob rau hauv zus tau tej cov 150 hli "ua-ntug" cov khoom thiab tag nrho cov tseem ceeb 200 hli cov khoom.