Karbid krem\u00edka (SiC) je kry\u0161talick\u00e1 zl\u00fa\u010denina krem\u00edka a uhl\u00edka, ktor\u00e1 sa pou\u017e\u00edva od 19. storo\u010dia v r\u00f4znych aplik\u00e1ci\u00e1ch, ako s\u00fa br\u00fasne papiere, br\u00fasne kot\u00fa\u010de, rezn\u00e9 n\u00e1stroje a dokonca aj v\u00fdmurovky priemyseln\u00fdch pec\u00ed. Okrem toho m\u00f4\u017ee SiC sl\u00fa\u017ei\u0165 aj ako s\u00fa\u010dasti odoln\u00e9 proti opotrebovaniu v \u010derpadl\u00e1ch a raketov\u00fdch motoroch.<\/p>\n
SiC sa m\u00f4\u017ee spr\u00e1va\u0165 ako izolant aj polovodi\u010d v z\u00e1vislosti od toho, ako bola zmenen\u00e1 kry\u0161t\u00e1lov\u00e1 \u0161trukt\u00fara pridan\u00edm pr\u00edmes\u00ed do jeho kry\u0161t\u00e1lovej \u0161trukt\u00fary; tento proces je zn\u00e1my ako dopovanie.<\/p>\n
Karbid krem\u00edka je keramick\u00fd materi\u00e1l s vlastnos\u0165ami, ktor\u00e9 z neho robia elektrick\u00fd izolant aj polovodi\u010d v z\u00e1vislosti od toho, ako sa do neho prid\u00e1vaj\u00fa pr\u00edmesi alebo dopanty. Univerz\u00e1lna povaha karbidu krem\u00edka z neho rob\u00ed neocenite\u013en\u00fd priemyseln\u00fd n\u00e1stroj pou\u017e\u00edvan\u00fd v mnoh\u00fdch r\u00f4znych oblastiach pou\u017eitia.<\/p>\n
Energeticky n\u00e1ro\u010dn\u00e9 aplik\u00e1cie, ktor\u00e9 musia pracova\u0165 pri vysok\u00fdch teplot\u00e1ch, ako s\u00fa turb\u00edny a vykurovacie syst\u00e9my, vyu\u017e\u00edvaj\u00fa jeho vynikaj\u00facu tepeln\u00fa vodivos\u0165. Okrem toho je v\u010faka svojej fyzik\u00e1lnej odolnosti a tvrdosti vhodn\u00fd na pou\u017eitie v rezn\u00fdch n\u00e1strojoch, ako s\u00fa br\u00fasne kot\u00fa\u010de. Jeho \u0161irok\u00e1 p\u00e1smov\u00e1 medzera mu navy\u0161e umo\u017e\u0148uje zvl\u00e1da\u0165 vy\u0161\u0161ie nap\u00e4tia a frekvencie ako tradi\u010dn\u00e9 zariadenia na b\u00e1ze krem\u00edka.<\/p>\n
Tento vyn\u00e1lez sa t\u00fdka spekan\u00fdch keramick\u00fdch materi\u00e1lov z karbidu krem\u00edka s extr\u00e9mne vysok\u00fdm elektrick\u00fdm odporom (a\u017e do pribli\u017ene 108 ohm cm), ktor\u00e9 boli vyroben\u00e9 pomocou spekania a pou\u017eit\u00e9 ako substr\u00e1ty pre integrovan\u00e9 obvody.<\/p>\n
Na dosiahnutie tohto cie\u013ea vyn\u00e1lezcovia pou\u017eili proces lisovania za tepla na v\u00fdrobu telesa spekan\u00e9ho karbidu krem\u00edka so submikr\u00f3nov\u00fdmi \u010dasticami karbidu krem\u00edka f\u00e1zy beta rovnomerne rozmiestnen\u00fdmi v nepor\u00e9znej dus\u00edkovej matrici pri teplot\u00e1ch bl\u00edzkych 2 000 \u00b0C na v\u00fdrobu spekan\u00e9ho karbidu krem\u00edka. V\u00fdsledn\u00fd materi\u00e1l vykazoval vysok\u00fd elektrick\u00fd odpor, ako aj n\u00edzky koeficient line\u00e1rnej roz\u0165a\u017enosti podobn\u00fd krem\u00edku.<\/p>\n
Spekan\u00e9 teles\u00e1 z karbidu krem\u00edka vyroben\u00e9 beztlakov\u00fdm spekan\u00edm maj\u00fa elektrick\u00e9 odpory ni\u017e\u0161ie ako s\u00fa potrebn\u00e9 pre substr\u00e1ty pre integrovan\u00e9 obvody a v\u00fdrazne ni\u017e\u0161ie tepeln\u00e9 vodivosti ako ich n\u00e1protivky, monokry\u0161talick\u00e9 materi\u00e1ly SiC.<\/p>\n
Vyn\u00e1lezcovia zistili, \u017ee spekan\u00fd karbid krem\u00edka obsahuj\u00faci zna\u010dn\u00e9 mno\u017estvo b\u00f3ru m\u00e1 ve\u013emi vysok\u00fd elektrick\u00fd odpor. Na pos\u00fadenie tohto vz\u0165ahu medzi koncentr\u00e1ciou nosi\u010dov n a \u0161pecifickou dielektrickou kon\u0161tantou es vykonali nieko\u013eko experiment\u00e1lnych vzoriek, v ktor\u00fdch sa do zmes\u00ed pr\u00e1\u0161kov\u00fdch \u010dast\u00edc karbidu krem\u00edka pred spekan\u00edm prid\u00e1val BeO a in\u00e9 element\u00e1rne dopanty zo skup\u00edn Va a Vb s valenciou i\u00f3nov +5.<\/p>\n
Karbid krem\u00edka (SiC) je jedn\u00fdm z najtvrd\u0161\u00edch dostupn\u00fdch materi\u00e1lov a vyzna\u010duje sa mimoriadne vysok\u00fdm Youngov\u00fdm modulom viac ako 400 GPa, \u010do mu umo\u017e\u0148uje odol\u00e1va\u0165 extr\u00e9mnym tlakom a teplot\u00e1m. SiC patr\u00ed aj medzi naj\u013eah\u0161ie a najizoluj\u00facej\u0161ie keramick\u00e9 materi\u00e1ly; je schopn\u00fd odol\u00e1va\u0165 kor\u00f3zii, er\u00f3znemu opotrebovaniu v d\u00f4sledku abr\u00e1zie, ako aj opotrebovaniu v d\u00f4sledku trenia, pri\u010dom m\u00e1 vynikaj\u00facu tepeln\u00fa vodivos\u0165 a n\u00edzku tepeln\u00fa roz\u0165a\u017enos\u0165, ke\u010f sa pou\u017e\u00edva ako elektroizola\u010dn\u00fd materi\u00e1l.<\/p>\n
Karbid krem\u00edka je kry\u0161t\u00e1l s kovalentnou v\u00e4zbou a jeho monokry\u0161t\u00e1l m\u00e1 relat\u00edvne ve\u013ek\u00fa tepeln\u00fa vodivos\u0165, zatia\u013e \u010do v spekanom stave toto \u010d\u00edslo kles\u00e1 v d\u00f4sledku rozptylu fon\u00f3nov na hraniciach kry\u0161t\u00e1lov\u00fdch z\u0155n, \u010d\u00edm sa vytv\u00e1raj\u00fa ochudobnen\u00e9 vrstvy nosi\u010dov v ka\u017edom kry\u0161t\u00e1lovom zrne na oboch stran\u00e1ch ka\u017edej hranice, \u010do br\u00e1ni tepeln\u00e9mu toku.<\/p>\n
S\u00fa\u010dasn\u00fd vyn\u00e1lez zah\u0155\u0148a vytvorenie izol\u00e1tora z karbidu krem\u00edka so zlep\u0161en\u00fdmi vlastnos\u0165ami kombin\u00e1ciou polovodi\u010dov\u00e9ho materi\u00e1lu typu p so spekan\u00fdm telesom SiC. Izol\u00e1tor obsahuje karbid krem\u00edka ako svoju prim\u00e1rnu zlo\u017eku a prvok poskytuj\u00faci elektroizola\u010dn\u00e9 vlastnosti (BN alebo Be), ako je zv\u00fd\u0161enie koncentr\u00e1cie nosi\u010dov o 5 \u00d7 1017 cm-3 alebo menej na oboch stran\u00e1ch hranice z\u0155n v spekanom stave, \u010do poskytuje vysok\u00e9 elektroizola\u010dn\u00e9 vlastnosti.<\/p>\n
Dopovanie karbidu krem\u00edka hlin\u00edkom, b\u00f3rom alebo g\u00e1liom vedie k vytvoreniu polovodi\u010dov\u00fdch materi\u00e1lov typu p, ktor\u00e9 maj\u00fa polovodiv\u00e9 vlastnosti. Izol\u00e1tory obsahuj\u00face tento karbid krem\u00edka p-typu maj\u00fa n\u00edzky elektrick\u00fd odpor a vysok\u00fa tepeln\u00fa vodivos\u0165 pre maxim\u00e1lny \u00fa\u010dinok.<\/p>\n
S\u00fa\u010dasn\u00fd vyn\u00e1lez zah\u0155\u0148a izol\u00e1tor, ktor\u00fd sa m\u00f4\u017ee pou\u017ei\u0165 na podporu polovodi\u010dov\u00fdch prvkov, ako je napr\u00edklad rezistor, rozpra\u0161ovac\u00ed ter\u010d alebo tenkovrstvov\u00fd rezistor. M\u00e1 nielen vynikaj\u00face elektrick\u00e9 a tepeln\u00e9 vlastnosti, ale m\u00f4\u017ee sa pochv\u00e1li\u0165 aj extr\u00e9mne n\u00edzkou hodnotou dielektrickej kon\u0161tanty. Okrem toho jeho v\u00fdroba s \u00fazkym hrdlom umo\u017e\u0148uje vysok\u00fa pr\u00fadov\u00fa hustotu bez prekro\u010denia tepeln\u00fdch obmedzen\u00ed materi\u00e1lu substr\u00e1tu.<\/p>\n
Karbid krem\u00edka (SiC) je v\u00fdnimo\u010dn\u00fd materi\u00e1l s vynikaj\u00facimi tepeln\u00fdmi vlastnos\u0165ami. V\u010faka n\u00edzkemu koeficientu tepelnej roz\u0165a\u017enosti a odolnosti vo\u010di praskaniu pri vystaven\u00ed vysok\u00fdm teplot\u00e1m dok\u00e1\u017ee SiC \u00fa\u010dinne odv\u00e1dza\u0165 teplo, \u010do je z\u00e1kladn\u00e1 vlastnos\u0165 pri aplik\u00e1ci\u00e1ch vy\u017eaduj\u00facich vysok\u00fa tepeln\u00fa \u00fa\u010dinnos\u0165. Okrem toho sa SiC m\u00f4\u017ee pochv\u00e1li\u0165 ve\u013ekou \u0161pecifickou tepelnou kapacitou, tak\u017ee m\u00f4\u017ee absorbova\u0165 obrovsk\u00e9 mno\u017estvo energie predt\u00fdm, ako za\u010dne proces expanzie.<\/p>\n
Tepeln\u00e1 roz\u0165a\u017enos\u0165 karbidu krem\u00edka z\u00e1vis\u00ed od jeho teploty a kry\u0161t\u00e1lovej \u0161trukt\u00fary, \u010do m\u00f4\u017ee ovplyvni\u0165 jeho v\u00fdkon a \u017eivotnos\u0165. Aby sme zabezpe\u010dili, \u017ee komponenty z karbidu krem\u00edka bud\u00fa spo\u013eahlivo fungova\u0165 aj v nepriazniv\u00fdch podmienkach prostredia, je nevyhnutn\u00e9 pochopi\u0165 jeho teplotn\u00fa z\u00e1vislos\u0165.<\/p>\n
Zlo\u017eenie m\u00f4\u017ee ma\u0165 vplyv aj na tepeln\u00fa roz\u0165a\u017enos\u0165 karbidu krem\u00edka; oxid ber\u00fdlia (BeO) pom\u00e1ha potl\u00e1\u010da\u0165 rozptyl fon\u00f3nov na hraniciach z\u0155n, \u010do vedie k ni\u017e\u0161ej tepelnej roz\u0165a\u017enosti v porovnan\u00ed s \u010dist\u00fdm krem\u00edkom a k ni\u017e\u0161\u00edm koeficientom tepelnej roz\u0165a\u017enosti (CTE) ako pri pr\u00e1ci pod vysok\u00fdm mechanick\u00fdm nam\u00e1han\u00edm. Tento faktor je obzvl\u00e1\u0161\u0165 v\u00fdznamn\u00fd pre v\u00fdkonn\u00e9 polovodi\u010dov\u00e9 zariadenia, ktor\u00e9 s\u00fa po\u010das prev\u00e1dzky vystaven\u00e9 siln\u00e9mu mechanick\u00e9mu nam\u00e1haniu.<\/p>\n
V\u010faka odolnosti proti kor\u00f3zii a oderu je to vynikaj\u00faci stavebn\u00fd materi\u00e1l, ide\u00e1lny pre chemick\u00e9 z\u00e1vody a mlyny s teplotami dosahuj\u00facimi 1 400 \u00b0C, a v\u010faka vysok\u00e9mu Youngovmu modulu 400 GPa je vhodn\u00fd pre pece s vysok\u00fdmi tlakmi.<\/p>\n
Pr\u00edrodn\u00fd moissanit sa vyskytuje len v stopov\u00fdch mno\u017estv\u00e1ch v niektor\u00fdch typoch meteoritov a v lo\u017eisk\u00e1ch korundu, ale v\u00e4\u010d\u0161ina moissanitu pred\u00e1van\u00e9ho ako drah\u00e9 kamene alebo pou\u017e\u00edvan\u00e9ho na spev\u0148ovanie kovov sa vyr\u00e1ba synteticky pomocou met\u00f3d, ako je napr\u00edklad vylu\u010dovanie krem\u00edkov\u00e9ho uhl\u00edka z pary, spekanie polym\u00e9rnych vl\u00e1kien obsahuj\u00facich krem\u00edk alebo vypa\u013eovanie \u017eiaruvzdorn\u00fdch obkladov obsahuj\u00facich krem\u00edk.<\/p>\n
Na zlep\u0161enie jeho obrobite\u013enosti a pevnosti v \u0165ahu bolo ned\u00e1vno vytvoren\u00e9 nov\u00e9 zlo\u017eenie SiC, ktor\u00e9 obsahuje menej oxidu ber\u00fdlia ako tradi\u010dn\u00e9 v\u00fdrobky SiC; je menej krehk\u00e9; m\u00e1 ni\u017e\u0161\u00ed koeficient tepelnej roz\u0165a\u017enosti; m\u00f4\u017ee sa pou\u017e\u00edva\u0165 v zariadeniach s vy\u0161\u0161\u00edm v\u00fdkonom; jeho v\u00fdroba je menej n\u00e1kladn\u00e1 ako v\u00fdroba \u010dist\u00e9ho karbidu krem\u00edka;<\/p>\n
Karbid krem\u00edka je jedn\u00fdm z najtvrd\u0161\u00edch a naj\u013eah\u0161\u00edch keramick\u00fdch materi\u00e1lov, ktor\u00fd sa vyzna\u010duje vynikaj\u00facou odolnos\u0165ou vo\u010di kor\u00f3zii, kyselin\u00e1m a z\u00e1sad\u00e1m, vynikaj\u00facou tepelnou vodivos\u0165ou a n\u00edzkymi hodnotami koeficientu tepelnej roz\u0165a\u017enosti - vlastnosti, ktor\u00e9 ho predur\u010duj\u00fa na pou\u017eitie vo vysokoteplotn\u00fdch prostrediach, ako s\u00fa pece na roztaven\u00e9 kovy alebo chemick\u00fd priemysel. Okrem toho jeho vysok\u00fd Youngov modul (> 400 GPa) pom\u00e1ha odol\u00e1va\u0165 nam\u00e1haniu v ohybe, ktor\u00e9 by inak zni\u010dilo in\u00fa keramiku.<\/p>\n
Krem\u00edk m\u00e1 relat\u00edvne \u00fazku p\u00e1smov\u00fa medzeru, ktor\u00e1 obmedzuje zmeny teploty a elektrick\u00e9ho po\u013ea, \u010do poskytuje v\u00fdhodu potrebn\u00fa pre aplik\u00e1cie v\u00fdkonovej elektroniky. Krem\u00edk, naj\u010dastej\u0161ie pou\u017e\u00edvan\u00fd polovodi\u010d, dosahuje svoje limity kv\u00f4li nedostato\u010dnej \u0161\u00edrke p\u00e1sma a prierazn\u00e9mu nap\u00e4tiu; ni\u00f3b preto pon\u00faka \u010fal\u0161iu mo\u017en\u00fa vo\u013ebu, ktor\u00e1 by mohla prekona\u0165 krem\u00edk pri pou\u017eit\u00ed pri vy\u0161\u0161\u00edch teplot\u00e1ch a elektrick\u00fdch poliach.<\/p>\n
Aby sa maximalizoval pln\u00fd potenci\u00e1l 4H-SiC, musia sa na jeho povrch aplikova\u0165 dielektrik\u00e1 s vysok\u00fdm obsahom k prostredn\u00edctvom silanov\u00fdch rozpra\u0161ovac\u00edch ter\u010dov, aby sa zn\u00ed\u017eila hustota rozhrania na jeho rozhran\u00ed s karbidom krem\u00edka a dielektrick\u00fdmi materi\u00e1lmi a zlep\u0161ili elektrick\u00e9 vlastnosti zariaden\u00ed.<\/p>\n
Viacer\u00e9 \u0161t\u00fadie sa zameriavaj\u00fa na v\u00fdvoj dielektr\u00edk s vysok\u00fdm k, ktor\u00e9 s\u00fa schopn\u00e9 pracova\u0165 na povrchu 4H-SiC. HfO2 a Y2O3 preuk\u00e1zali svoju hodnotu zlep\u0161en\u00edm elektrick\u00e9ho v\u00fdkonu zv\u00fd\u0161en\u00edm prierazn\u00e9ho elektrick\u00e9ho po\u013ea, ale ich vysok\u00fd stav rozhrania zost\u00e1va prek\u00e1\u017ekou pre pln\u00e9 nasadenie v zariadeniach.<\/p>\n
Stanfordsk\u00ed v\u00fdskumn\u00edci navrhli met\u00f3du na vytvorenie vysokokvalitn\u00e9ho izol\u00e1tora z karbidu krem\u00edka v rozsahu waferov pomocou fotochemick\u00e9ho leptania a chemicko-mechanick\u00e9ho le\u0161tenia, potom pomocou menej dopovan\u00fdch vrstiev zariadenia na silne dopovanej obetnej vrstve pred pou\u017eit\u00edm fotochemick\u00e9ho leptania a chemicko-mechanick\u00e9ho le\u0161tenia na jej odstr\u00e1nenie pomocou fotochemick\u00e9ho leptania a chemicko-mechanick\u00e9ho le\u0161tenia, \u010d\u00edm sa odhal\u00ed SiC a umo\u017en\u00ed sa vytvorenie vysokokvalitn\u00fdch izol\u00e1torov vhodn\u00fdch pre kvantov\u00e9 a neline\u00e1rne fotonick\u00e9 aplik\u00e1cie.<\/p>\n
Aj napriek tomuto zauj\u00edmav\u00e9mu v\u00fdvoju je e\u0161te pr\u00edli\u0161 skoro na to, aby sa dielektrik\u00e1 s vysok\u00fdm kiv\u00fdkonom implementovali do komer\u010dn\u00fdch zariaden\u00ed na b\u00e1ze 4H-SiC. Preto bude potrebn\u00e9 presk\u00fama\u0165 in\u00e9 met\u00f3dy v\u00fdroby kovovo-izol\u00e1torovo-polovodi\u010dov\u00fdch zariaden\u00ed na SiC, k\u00fdm sa tento cie\u013e podar\u00ed dosiahnu\u0165.<\/p>","protected":false},"excerpt":{"rendered":"
Silicon carbide (SiC) is a crystalline compound of silicon and carbon used since the 19th century in applications as varied as sandpaper, grinding wheels, cutting tools and even industrial furnace linings. Additionally, SiC can also serve as wear-resistant parts in pumps and rocket engines. SiC can act both as an insulator and semiconductor depending on […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-gradient":""}},"footnotes":""},"categories":[64],"tags":[],"class_list":["post-479","post","type-post","status-publish","format-standard","hentry","category-knowledge"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/posts\/479","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/comments?post=479"}],"version-history":[{"count":1,"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/posts\/479\/revisions"}],"predecessor-version":[{"id":480,"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/posts\/479\/revisions\/480"}],"wp:attachment":[{"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/media?parent=479"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/categories?post=479"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ceramicatijolart.com\/sk\/wp-json\/wp\/v2\/tags?post=479"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}