Cov tub ntxhais technology rau kev loj hlob ntawmSiC epitaxialcov ntaub ntawv yog thawj qhov tsis xws luag tswj thev naus laus zis, tshwj xeeb tshaj yog rau cov cuab yeej tswj xyuas tsis raug uas ua rau cov cuab yeej tsis ua hauj lwm lossis kev ntseeg tau degradation. Txoj kev tshawb no ntawm cov txheej txheem ntawm substrate defects ncua mus rau hauv lub epitaxial txheej thaum lub sij hawm txoj kev loj hlob ntawm epitaxial, kev hloov thiab transformation txoj cai ntawm tsis xws luag nyob rau hauv lub interface ntawm lub substrate thiab epitaxial txheej, thiab lub nucleation mechanism ntawm qhov tsis xws luag yog lub hauv paus rau qhia meej txog kev sib raug zoo ntawm lub substrate. substrate defects thiab epitaxial structural defects, uas muaj peev xwm coj zoo substrate soj ntsuam thiab epitaxial txheej txheem optimization.
Qhov tsis xws luag ntawmsilicon carbide epitaxial txheejFeem ntau muab faib ua ob pawg: crystal defects thiab nto morphology defects. Crystal defects, nrog rau cov ntsiab lus tsis xws luag, ntsia hlau dislocations, microtubule defects, ntug dislocations, thiab lwm yam., feem ntau yog los ntawm qhov tsis xws luag ntawm SiC substrates thiab diffuse mus rau hauv epitaxial txheej. Deg morphology tsis xws luag tuaj yeem pom ncaj qha nrog lub qhov muag liab qab siv lub tshuab tsom iav thiab muaj cov yam ntxwv morphological. Deg morphology defects mas muaj xws li: Kos, daim duab peb sab defect, Carrot defect, downfall, thiab Particle, raws li qhia nyob rau hauv daim duab 4. Thaum lub sij hawm lub epitaxial txheej txheem, txawv teb chaws hais, substrate defects, nto puas, thiab epitaxial txheej txheem deviations tej zaum yuav tag nrho cov cuam tshuam rau lub zos kauj ruam khiav. hom kev loj hlob, uas ua rau nto morphology defects.
Table 1. Ua rau tsim cov matrix tsis xws luag thiab nto morphology defects hauv SiC epitaxial txheej
Point tsis xws luag
Cov ntsiab lus tsis xws luag yog tsim los ntawm qhov chaw ua haujlwm lossis qhov khoob ntawm ib qho chaw ib leeg lossis ob peb lub ntsiab lus lattice, thiab lawv tsis muaj qhov txuas ntxiv. Point defects yuav tshwm sim nyob rau hauv txhua txoj kev tsim khoom, tshwj xeeb tshaj yog nyob rau hauv ion implantation. Txawm li cas los xij, lawv nyuaj rau kev txheeb xyuas, thiab kev sib raug zoo ntawm kev hloov pauv ntawm cov ntsiab lus tsis xws luag thiab lwm yam tsis xws luag kuj yog qhov nyuaj heev.
Micropipes (MP)
Micropipes yog hollow ntsia hlau dislocations uas propagate raws txoj kev loj hlob axis, nrog ib tug Burgers vector <0001>. Txoj kab uas hla ntawm microtubes yog li ntawm ib feem ntawm ib micron mus rau kaum ntawm microns. Microtubes qhia qhov loj zoo li qhov chaw ntawm qhov chaw ntawm SiC wafers. Feem ntau, qhov ceev ntawm microtubes yog li 0.1 ~ 1cm-2 thiab tseem txo qis hauv kev lag luam wafer ntau lawm kev soj ntsuam zoo.
Screw dislocations (TSD) thiab ntug dislocations (TED)
Dislocations hauv SiC yog qhov tseem ceeb ntawm cov cuab yeej degradation thiab tsis ua haujlwm. Ob leeg ntsia hlau dislocations (TSD) thiab ntug dislocations (TED) khiav raws txoj kev loj hlob axis, nrog Burgers vectors ntawm <0001> thiab 1/3<11–20>, ntsig txog.
Ob lub ntsia hlau dislocations (TSD) thiab ntug dislocations (TED) tuaj yeem txuas ntxiv los ntawm substrate mus rau qhov chaw wafer thiab nqa me me qhov chaw zoo li qhov chaw (Daim duab 4b). Feem ntau, qhov ceev ntawm ntug dislocations yog li 10 npaug ntawm cov ntsia hlau dislocations. Extended ntsia hlau dislocations, uas yog, ncua ntawm lub substrate mus rau lub epilayer, kuj yuav hloov mus rau lwm yam tsis xws luag thiab propagate raws txoj kev loj hlob axis. ThaumSiC epitaxialkev loj hlob, ntsia hlau dislocations hloov mus rau hauv stacking faults (SF) los yog carrot defects, thaum ntug dislocations nyob rau hauv epilayers tau pom tias yuav hloov los ntawm basal dav hlau dislocations (BPDs) tau txais los ntawm substrate thaum lub sij hawm epitaxial loj hlob.
Basic dav hlau dislocation (BPD)
Nyob ntawm SiC basal dav hlau, nrog Burgers vector ntawm 1/3 <11–20>. BPDs tsis tshua muaj tshwm sim ntawm qhov chaw ntawm SiC wafers. Lawv feem ntau yog concentrated nyob rau hauv lub substrate nrog ib tug ceev ntawm 1500 cm-2, thaum lawv ceev nyob rau hauv lub epilayer tsuas yog hais txog 10 cm-2. Kev kuaj pom ntawm BPDs siv photoluminescence (PL) qhia tawm cov yam ntxwv, raws li pom hauv daim duab 4c. ThaumSiC epitaxialkev loj hlob, txuas ntxiv BPDs tuaj yeem hloov mus rau hauv qhov tsis raug (SF) lossis ntug kev cuam tshuam (TED).
Stacking faults (SFs)
Cov teeb meem nyob rau hauv lub stacking sequence ntawm SiC basal dav hlau. Stacking faults tuaj yeem tshwm sim hauv cov txheej txheem epitaxial los ntawm kev txais SFs hauv lub substrate, los yog muaj feem xyuam nrog kev txuas ntxiv thiab hloov pauv ntawm lub dav hlau basal dislocations (BPDs) thiab threading screw dislocations (TSDs). Feem ntau, qhov ceev ntawm SFs yog tsawg dua 1 cm-2, thiab lawv nthuav tawm cov duab peb sab thaum kuaj pom siv PL, raws li qhia hauv daim duab 4e. Txawm li cas los xij, ntau hom stacking faults tuaj yeem tsim nyob rau hauv SiC, xws li Shockley hom thiab Frank hom, vim tias txawm tias me me ntawm stacking zog tsis sib haum ntawm cov dav hlau tuaj yeem ua rau muaj qhov tsis sib xws hauv cov txheej txheem stacking.
Kev poob qis
Qhov kev poob qis feem ntau tshwm sim los ntawm qhov poob qis ntawm cov phab ntsa sab sauv thiab sab ntawm cov tshuaj tiv thaiv chamber thaum lub sij hawm txoj kev loj hlob, uas tuaj yeem ua kom zoo dua los ntawm kev ua kom zoo dua cov txheej txheem tu ncua sij hawm ntawm cov tshuaj tiv thaiv chamber graphite consumables.
Daim duab peb sab defect
Nws yog 3C-SiC polytype suav nrog uas txuas mus rau saum npoo ntawm SiC epilayer raws lub dav hlau basal, raws li qhia hauv daim duab 4g. Nws tuaj yeem tsim los ntawm cov khoom poob rau ntawm qhov chaw ntawm SiC epilayer thaum lub sij hawm epitaxial loj hlob. Cov khoom yog embedded nyob rau hauv lub epilayer thiab cuam tshuam rau txoj kev loj hlob, ua rau 3C-SiC polytypes inclusions, uas qhia tau hais tias ntse-angled triangular nto nta nrog cov hais nyob rau hauv lub vertices ntawm lub triangular cheeb tsam. Ntau cov kev tshawb fawb kuj tau hais txog keeb kwm ntawm polytypes suav nrog rau qhov chaw khawb, micropipes, thiab qhov tsis raug ntawm txoj kev loj hlob.
Carrot defect
Carrot defect yog ib tug stacking txhaum complex nrog ob xaus nyob rau hauv lub TSD thiab SF basal siv lead ua dav hlau, txiav los ntawm ib tug Frank-hom dislocation, thiab qhov luaj li cas ntawm cov zaub ntug hauv paus muaj feem xyuam rau lub prismatic stacking txhaum. Kev sib xyaw ua ke ntawm cov yam ntxwv no ua rau saum npoo morphology ntawm cov zaub ntug hauv paus tsis xws luag, uas zoo li cov zaub ntug hauv paus nrog qhov ntom ntawm tsawg dua 1 cm-2, raws li qhia hauv daim duab 4f. Carrot defects tau yooj yim tsim ntawm polishing khawb, TSDs, los yog substrate defects.
Kos
Kev khawb yog kev puas tsuaj rau ntawm qhov chaw ntawm SiC wafers tsim thaum lub sij hawm tsim khoom, raws li qhia hauv daim duab 4h. Kos rau ntawm SiC substrate tuaj yeem cuam tshuam nrog kev loj hlob ntawm cov epilayer, tsim cov kab ntau qhov sib txawv hauv cov epilayer, lossis khawb tuaj yeem ua lub hauv paus rau kev tsim cov zaub ntug hauv paus. Yog li ntawd, nws yog ib qho tseem ceeb kom ua tau zoo polishing SiC wafers vim tias cov khawb no tuaj yeem muaj kev cuam tshuam loj rau kev ua haujlwm ntawm cov cuab yeej thaum lawv tshwm sim hauv thaj chaw nquag ntawm lub cuab yeej.
Lwm qhov chaw morphology defects
Cov kauj ruam bunching yog ib qho chaw tsis xws luag tsim thaum lub sij hawm SiC epitaxial txoj kev loj hlob, uas ua rau obtuse daim duab peb sab los yog trapezoidal nta ntawm qhov chaw ntawm SiC epilayer. Muaj ntau ntau lwm yam tsis xws luag, xws li nto pits, pob thiab stains. Cov kev tsis zoo no feem ntau yog tshwm sim los ntawm cov txheej txheem kev loj hlob tsis zoo thiab kev tshem tawm tsis tiav ntawm polishing puas tsuaj, uas cuam tshuam rau kev ua haujlwm ntawm cov cuab yeej.
Post lub sij hawm: Jun-05-2024