Ib txheej epitaxial yog ib zaj duab xis nyias nyias uas loj hlob ntawm ib lub wafer substrate los ntawm cov txheej txheem epitaxial; lub substrate wafer thiab zaj duab xis epitaxial yog hu ua epitaxial wafer. Ntawm cov no, kev loj hlob ntawm silicon carbide epitaxial txheej ntawm ib lub conductive silicon carbide substrate tsim ib homogeneous silicon carbide epitaxial wafer, uas tuaj yeem tsim ntxiv rau hauv cov khoom siv fais fab xws li Schottky diodes, MOSFETs, thiab IGBTs. Hom substrate siv dav tshaj plaws yog 4H-SiC substrate.
Vim tias yuav luag txhua yam khoom siv tau tsim los ntawm cov txheej epitaxial, qhov zoo ntawm cov txheej epitaxial muaj qhov cuam tshuam loj heev rau kev ua haujlwm ntawm cov khoom siv. Txawm li cas los xij, qhov zoo ntawm cov txheej epitaxial raug cuam tshuam los ntawm kev ua cov siv lead ua thiab cov khoom siv hauv paus, tso nws rau ntawm qhov tseem ceeb hauv kev lag luam thiab ua lub luag haujlwm tseem ceeb hauv nws txoj kev loj hlob.
Cov txheej txheem tseem ceeb rau kev npaj cov txheej silicon carbide epitaxial suav nrog: vapor deposition; liquid phase epitaxy (LPE); molecular beam epitaxy (MBE); thiab chemical vapor deposition (CVD). Ntawm cov no, chemical vapor deposition (CVD) yog txoj kev siv dav tshaj plaws rau 4H-SiC homogeneous epitaxy. 4H-SiC CVD epitaxy feem ntau siv cov khoom siv CVD, uas ua kom muaj kev sib txuas ntawm 4H-SiC crystal structure nyob rau hauv qhov kub siab.
Hauv cov khoom siv CVD, lub substrate tsis tuaj yeem muab tso ncaj qha rau ntawm qhov chaw hlau lossis tsuas yog muab tso rau ntawm lub hauv paus rau epitaxial deposition, vim qhov no cuam tshuam nrog ntau yam cuam tshuam xws li cov pa roj ntws (kab rov tav, ntsug), kub, siab, kho, thiab kev ua qias tuaj ntawm cov khoom me me uas poob tawm. Yog li ntawd, yuav tsum muaj lub hauv paus txhawb nqa; lub substrate raug muab tso rau ntawm lub tais, thiab epitaxial deposition tom qab ntawd ua rau ntawm lub substrate siv CVD thev naus laus zis. Lub hauv paus txhawb nqa no yog SiC-coated graphite puag.
Ua ib feem tseem ceeb, cov graphite substrate muaj lub zog tshwj xeeb thiab cov modulus tshwj xeeb, nrog rau kev ua haujlwm zoo thermal shock thiab corrosion residue. Txawm li cas los xij, thaum lub sijhawm tsim khoom, cov graphite raug rau corrosion thiab hmoov shedding vim yog cov pa roj corrosive thiab cov khoom seem organometallic, ua rau lub neej ua haujlwm ntawm cov substrate txo qis. Tib lub sijhawm, cov hmoov graphite uas raug shed tuaj yeem ua rau cov chips paug. Hauv kev tsim cov silicon carbide epitaxial wafers, nws tau dhau los ua qhov nyuaj dua los ua kom tau raws li cov kev cai nruj dua rau cov ntaub ntawv graphite, ua rau lawv txoj kev loj hlob thiab kev siv tau yooj yim txwv tsis pub. Yog li ntawd,txheej txheem txheej txheemtau tshwm sim los ua ib qho kev daws teeb meem.
Cov txiaj ntsig ntawm SiC Coatings hauv Kev Lag Luam Semiconductor
Cov khoom siv lub cev thiab tshuaj ntawm cov txheej yuav tsum ua tau raws li qhov yuav tsum tau ua kom kub thiab tiv taus corrosion, vim tias cov no cuam tshuam ncaj qha rau cov khoom tsim tawm thiab lub neej ntev. Cov khoom siv SiC muaj lub zog siab, tawv heev, qhov coefficient qis ntawm thermal nthuav dav, thiab thermal conductivity zoo heev, ua rau nws yog cov khoom siv tseem ceeb rau kev tsim kho kub thiab semiconductor. Thaum siv rau graphite substrates, nws cov txiaj ntsig suav nrog:
1) SiC tiv taus xeb thiab tuaj yeem npog tag nrho cov graphite substrate. Nws qhov ceev ceev tiv thaiv kev puas tsuaj los ntawm cov pa roj corrosive.
2) SiC muaj kev ua tau zoo ntawm cov cua sov thiab muaj zog sib txuas nrog cov graphite substrate, ua kom cov txheej txheem tseem zoo txawm tias tom qab rov ua dua qhov kub thiab txias siab-qis.
3) SiC muaj kev ruaj khov tshuaj zoo heev, tiv thaiv kev ua tsis tiav ntawm cov txheej txheem hauv qhov kub thiab txias, cov huab cua corrosive.
Tsis tas li ntawd xwb, cov cub tawg epitaxial uas ua los ntawm cov khoom sib txawv xav tau cov tais graphite nrog cov kev ua tau zoo tshwj xeeb. Cov coefficient thermal expansion ntawm cov khoom siv graphite yuav tsum sib xws nrog qhov kub ntawm qhov cub tawg epitaxial. Piv txwv li, txij li thaum qhov kub ntawm kev loj hlob rau silicon carbide epitaxy siab, cov tais uas muaj qib siab ntawm cov coefficient thermal expansion matching yog qhov yuav tsum tau ua. Cov coefficient thermal expansion ntawm SiC txawv me ntsis ntawm graphite, ua rau nws yog cov khoom siv nyiam rau kev txheej cov nplaim ntawm graphite substrates.
SiC muaj ntau hom siv lead ua, feem ntau yog 3C, 4H, thiab 6H, txhua hom siv tau rau ntau yam kev siv. Piv txwv li, 4H-SiC siv los tsim cov khoom siv hluav taws xob siab; 6H-SiC yog qhov ruaj khov tshaj plaws thiab siv los tsim cov khoom siv optoelectronic; thiab 3C-SiC, vim nws cov qauv zoo sib xws rau GaN, siv los tsim cov txheej GaN epitaxial rau kev tsim cov khoom siv SiC-GaN RF. 3C-SiC kuj tseem hu ua β-SiC. Ib qho kev siv tseem ceeb ntawm β-SiC yog ua cov khoom siv nyias-zaj duab xis thiab txheej; yog li ntawd, β-SiC tam sim no yog cov khoom siv tseem ceeb siv rau txheej.
Raws li ib qho khoom siv tau dav hauv kev tsim khoom semiconductor, SiC coatings feem ntau yog siv rau hauv cov txheej txheem xws li kev npaj substrate, epitaxy, oxidation thiab diffusion, etching, thiab ion implantation. Cov khoom siv lub cev thiab tshuaj lom neeg ntawm cov txheej txheem yuav tsum ua tau raws li cov kev cai nruj rau kev tiv taus kub siab thiab kev tiv taus corrosion, vim tias cov no cuam tshuam ncaj qha rau cov khoom tsim tawm thiab lub neej ntev. Yog li ntawd, kev npaj cov txheej txheem SiC yog qhov tseem ceeb.
Cov Txheej Txheem rau Kev Npaj Silicon Carbide Coatings
Tam sim no, cov txheej txheem tseem ceeb rau kev npaj SiC coatings suav nrog txoj kev sol-gel, txoj kev embedding, txhuam txheej, plasma spraying, tshuaj lom neeg vapor reaction (CVR), thiab tshuaj lom neeg vapor deposition (CVD).
Txoj Kev Muab Tso Rau Hauv
Txoj kev no yog ib hom kev sintering uas kub thiab txias heev. Nws feem ntau siv cov hmoov silicon (Si) thiab hmoov carbon (C) ua cov hmoov embedding. Ib lub substrate graphite raug muab tso rau hauv cov hmoov embedding thiab sintered ntawm qhov kub siab hauv huab cua inert gas, thaum kawg tsim ib txheej SiC rau ntawm qhov chaw ntawm lub substrate graphite. Txoj kev no muaj cov txheej txheem yooj yim thiab kev sib txuas zoo ntawm cov txheej thiab lub substrate; txawm li cas los xij, cov txheej tsis zoo sib xws raws li qhov tuab thiab yooj yim tsim ntau lub qhov hws, ua rau tsis zoo tiv taus oxidation.
Txoj Kev Txheej Txhuam
Txoj kev txhuam txheej feem ntau yog siv cov khoom siv ua kua rau saum npoo ntawm cov graphite substrate, tom qab ntawd kho cov khoom ntawm qhov kub tshwj xeeb kom ua tau cov txheej. Txoj kev no yooj yim thiab pheej yig; txawm li cas los xij, cov txheej tshwm sim qhia tias tsis nplaum rau cov substrate, tsis sib xws, thiab nyias nyias nrog kev tiv thaiv oxidation qis, uas xav tau cov txheej txheem ntxiv.
Txoj Kev Txau Plasma
Txoj kev txau plasma yog siv rab phom plasma los txau cov khoom siv raw uas yaj lossis ib nrab yaj rau saum npoo ntawm graphite substrate, uas tom qab ntawd khov thiab sib txuas ua ke los ua ib txheej. Txoj kev no yooj yim rau kev khiav lag luam thiab tuaj yeem tsim cov txheej silicon carbide uas tuab heev; txawm li cas los xij, cov txheej txheem tshwm sim feem ntau nyias dhau, ua rau tsis kam oxidation. Yog li ntawd, nws feem ntau yog siv rau hauv kev npaj cov txheej txheem SiC composite los txhim kho qhov zoo ntawm txheej.
Txoj Kev Siv Gel-Sol
Txoj kev gel-sol feem ntau yog npaj cov tshuaj sol uas sib npaug, pob tshab los pleev rau saum npoo ntawm cov khoom siv. Tom qab ziab ua gel, cov khoom siv raug sintered los ua cov txheej. Txoj kev no yooj yim rau kev khiav lag luam thiab pheej yig; txawm li cas los xij, cov txheej txheem tshwm sim raug kev txom nyem los ntawm qhov tsis zoo xws li kev tiv thaiv kev poob siab thermal qis thiab nyiam tawg, txwv tsis pub lawv siv dav.
Txoj Kev Tshuaj Lom Zem Ua Pa (CVR)
CVR feem ntau siv Si thiab SiO₂ hmoov los tsim SiO₂ pa dej ntawm qhov kub siab, ua rau muaj ntau yam kev tshuaj lom neeg ntawm qhov chaw ntawm Si substrate los tsim ib txheej SiC. Cov txheej SiC uas tsim los ntawm txoj kev no sib txuas zoo rau lub substrate; txawm li cas los xij, qhov kub ntawm kev ua tshuaj lom neeg siab, thiab tus nqi kuj siab heev.
Kev Tso Pa Tshuaj Lom Zem (CVD)
CVD tam sim no yog lub thev naus laus zis tseem ceeb rau kev npaj SiC coatings rau ntawm cov substrate nto. Cov txheej txheem tseem ceeb cuam tshuam nrog ntau yam kev sib xyaw ua ke ntawm cov tshuaj reactants gaseous thiab cov substrate nto, thaum kawg ua rau muaj SiC coating. SiC coatings tsim los ntawm CVD technology sib txuas zoo rau ntawm cov substrate nto thiab tuaj yeem txhim kho cov khoom siv substrate qhov kev tiv thaiv oxidation thiab ablation tsis kam; txawm li cas los xij, txoj kev no xav tau lub sijhawm tso dej ntev, thiab cov pa roj reaction muaj qee yam khoom lom.
Cov Qauv Hauv SiC Coatings
Cov txheej SiC feem ntau yog siv ua cov khoom siv hauv kev tsim khoom semiconductor, nrog rau cov ntsuas kev ua tau zoo tseem ceeb suav nrog kev sib xws ntawm cov txheej, coefficient ntawm thermal expansion, thiab thermal conductivity. Txawm hais tias muaj kev thov hauv tsev rau SiC coatings hauv Suav teb, cov thev naus laus zis tseem tsis tau paub tab. Txawv teb chaws, tsuas yog ib lub tuam txhab Asmeskas ua haujlwm hauv daim teb no, thiab nws cov khoom kim heev.
Cov nkoj siv lead uayog cov khoom siv tau siv hauv kev tsim khoom epitaxial uas tuaj yeem hloov SiC-coated graphite, txawm hais tias qhov ntim khoom lag luam me me. Tom ntej no yog TaC-coated graphite, uas muaj kev tiv thaiv xeb tshuaj zoo dua li graphite liab qab lossis SiC-coated graphite, tab sis nws kim heev thiab tseem nyob rau theem pib ntawm kev txhim kho. Tam sim no, cov tuam txhab hauv tsev xws liLiufang semiconductor, Semicera, thiabVetek Semiconductorlawv koom nrog R&D hauv thaj chaw no.
Lub sijhawm tshaj tawm: Tsib Hlis-20-2026