Ta yaya Layer epitaxial ke taimakawa na'urorin semiconductor?

Asalin sunan wafer epitaxial

Na farko, bari mu yada ƙaramin ra'ayi: shirye-shiryen wafer ya ƙunshi manyan hanyoyin haɗin gwiwa guda biyu: shirye-shiryen substrate da tsarin epitaxial. Substrate wani wafer ne da aka yi da kayan kristal guda ɗaya. Substrate na iya shiga cikin tsarin masana'antar wafer kai tsaye don samar da na'urorin semiconductor, ko kuma ana iya sarrafa shi ta hanyar tsarin epitaxial don samar da wafer na epitaxial. Epitaxy yana nufin tsarin haɓaka sabon Layer na kristal guda ɗaya akan nau'in kristal guda ɗaya wanda aka sarrafa a hankali ta hanyar yankan, niƙa, gogewa, da dai sauransu. Sabon kristal guda ɗaya na iya zama abu ɗaya kamar na substrate, ko kuma yana iya zama abubuwa daban-daban (mai kama da juna) epitaxy ko heteroepitaxy). Saboda sabon Layer crystal guda ɗaya ya shimfiɗa kuma yana girma bisa ga tsarin crystal na substrate, ana kiran shi Layer epitaxial (kauri yawanci 'yan microns ne, ɗaukar silicon a matsayin misali: ma'anar ci gaban silicon epitaxial yana kan siliki guda ɗaya). crystal substrate tare da wani kristal fuskantarwa. Layer ana kiransa wafer epitaxial (epitaxial wafer = epitaxial Layer + substrate). Lokacin da na'urar da aka yi a kan epitaxial Layer, shi ake kira tabbatacce epitaxy. Idan an yi na'urar a kan ma'auni, ana kiranta reverse epitaxy. A wannan lokacin, Layer na epitaxial yana taka rawa kawai.

Wafer da aka goge

Hanyoyin haɓakar Epitaxial

Molecular beam epitaxy (MBE): fasaha ce ta haɓakar haɓakar semiconductor epitaxial da aka yi a ƙarƙashin matsanancin matsanancin yanayi. A cikin wannan fasaha, ana fitar da kayan tushe a cikin nau'i na katako na atoms ko kwayoyin halitta sannan a ajiye su a kan ma'auni na crystalline. MBE ingantaccen fasaha ne mai sarrafa semiconductor bakin ciki na haɓaka fim wanda zai iya sarrafa kauri da aka adana daidai a matakin atomic.
Metal Organic CVD (MOCVD): A cikin tsarin MOCVD, ƙarfe na ƙarfe da gas na hydride N gas wanda ke ɗauke da abubuwan da ake buƙata ana ba da su zuwa ga ma'aunin a yanayin zafin da ya dace, ana yin maganin sinadarai don samar da kayan da ake buƙata na semiconductor, kuma ana ajiye su a kan substrate. on, yayin da sauran mahadi da dauki kayayyakin da aka sallama.
Tururi lokaci epitaxy (VPE): Tururi lokaci epitaxy wata muhimmiyar fasaha ce da aka saba amfani da ita wajen samar da na'urorin semiconductor. Babban ka'idar ita ce jigilar tururin abubuwa na farko ko mahadi a cikin iskar gas mai ɗaukar kaya, da saka lu'ulu'u a kan ƙasa ta hanyar halayen sinadarai.

Wadanne matsaloli ne tsarin epitaxy ke magance?

Babban kayan kristal guda ɗaya kaɗai ba za su iya biyan buƙatun girma na kera na'urorin semiconductor daban-daban ba. Saboda haka, ci gaban epitaxial, fasaha mai girma na siriri-Layi ɗaya na kristal, an haɓaka shi a ƙarshen 1959. Don haka wane takamaiman gudummawar fasahar epitaxy ke da shi don haɓaka kayan?

Don silicon, lokacin da fasahar ci gaban silicon epitaxial ta fara, hakika lokaci ne mai wuyar gaske don samar da mitar siliki mai ƙarfi da ƙarfin wutar lantarki. Daga ra'ayi na ka'idodin transistor, don samun mitar mita da babban iko, raguwar ƙarfin wutar lantarki na yanki mai tattarawa dole ne ya zama babba kuma juriya na jerin dole ne ƙarami, wato, raguwar ƙarfin lantarki dole ne ƙarami. Na farko yana buƙatar cewa juriya na kayan aiki a cikin wurin tattarawa ya kamata ya zama babba, yayin da na ƙarshe ya buƙaci tsayayyar kayan da ke cikin wurin tattarawa ya zama ƙasa. Lardunan biyu suna cin karo da juna. Idan an rage kauri daga cikin kayan da ke cikin yanki mai tarawa don rage juriya na jerin, wafer siliki zai zama bakin ciki da rauni don sarrafawa. Idan an rage juriya na kayan aiki, zai saba wa buƙatun farko. Duk da haka, ci gaban fasahar epitaxial ya yi nasara. warware wannan wahala.

Magani: Shuka babban Layer epitaxial mai juriya akan ƙaramin juriya mai ƙarancin juriya, kuma sanya na'urar akan Layer epitaxial. Wannan babban juriya na epitaxial Layer yana tabbatar da cewa bututu yana da babban ƙarfin rushewa, yayin da ƙananan juriya yana rage juriya na substrate, ta haka yana rage raguwar ƙarfin lantarki, ta haka ne ya warware sabani tsakanin su biyun.

Bugu da kari, fasahohin epitaxy irin su tururi lokaci epitaxy da ruwa lokaci epitaxy na GaAs da sauran III-V, II-VI da sauran kwayoyin fili semiconductor kayan suma an haɓaka sosai kuma sun zama tushen mafi yawan na'urorin microwave, na'urorin optoelectronic, iko. Yana da wani makawa tsari fasaha don samar da na'urori, musamman nasarar aikace-aikace na kwayoyin katako da karfe Organic tururi lokaci epitaxy fasahar a bakin ciki yadudduka, superlatices, rijiyoyin ƙididdigewa, matsananciyar superlatices, da matakin atomic-level thin-Layer epitaxy, wanda sabon mataki ne a cikin binciken semiconductor. Ci gaban "injin bel na makamashi" a fagen ya kafa tushe mai tushe.

A aikace-aikace masu amfani, na'urorin semiconductor masu faɗi kusan koyaushe ana yin su akan layin epitaxial, kuma wafer siliki carbide da kanta kawai ke aiki azaman ma'auni. Saboda haka, kula da epitaxial Layer wani muhimmin bangare ne na masana'antun masana'antu na bandgap mai fadi.

7 manyan ƙwarewa a cikin fasahar epitaxy

1. High (low) juriya epitaxial yadudduka za a iya epitaxially girma a kan low (high) juriya substrates.
2. Nau'in nau'in nau'in epitaxial na N (P) na iya girma a kan nau'in nau'in P (N) don samar da haɗin PN kai tsaye. Babu matsala ta ramuwa yayin amfani da hanyar watsawa don yin mahaɗar PN akan madaidaicin kristal guda ɗaya.
3. Haɗe tare da fasahar maskurin, zaɓaɓɓen ci gaban epitaxial ana aiwatar da shi a cikin wuraren da aka keɓe, ƙirƙirar yanayi don samar da haɗaɗɗun da'irori da na'urori tare da sifofi na musamman.
4. Za'a iya canza nau'in da maida hankali na doping bisa ga buƙatun yayin tsarin girma na epitaxial. Canjin natsuwa na iya zama canji kwatsam ko sauyi a hankali.
5. Zai iya girma iri-iri, mai yawa, nau'i-nau'i masu yawa da ƙananan ƙananan ƙananan ƙananan abubuwa tare da sassa daban-daban.
6. Ana iya yin girma na epitaxial a yanayin zafi ƙasa da ma'anar narkewar kayan, haɓakar haɓakar haɓakar haɓakawa, kuma ana iya samun ci gaban epitaxial na kauri-matakin atomic.
7. Yana iya girma guda crystal kayan da ba za a iya ja, kamar GaN, guda crystal yadudduka na manyan makarantu da quaternary mahadi, da dai sauransu.