Izingqimba ze-epitaxial zisiza kanjani amadivayisi e-semiconductor?

Umsuka wegama elithi epitaxial wafer

Okokuqala, ake sithande umqondo omncane: ukulungiswa kwe-wafer kuhlanganisa izixhumanisi ezimbili ezinkulu: ukulungiswa kwe-substrate kanye nenqubo ye-epitaxial. I-substrate iyi-wafer eyenziwe ngezinto ze-semiconductor single crystal. I-substrate ingangena ngqo enkambisweni yokukhiqiza i-wafer ukuze ikhiqize amadivayisi e-semiconductor, noma ingacutshungulwa ngezinqubo ze-epitaxial ukuze ikhiqize ama-wafer e-epitaxial. I-Epitaxy ibhekisela enkambisweni yokukhulisa ungqimba olusha lwekristalu elilodwa ku-substrate eyodwa yekristalu ecutshungulwe ngokucophelela ngokusika, ukugaya, ukupholisha, njll. Ikristalu entsha eyodwa ingaba yinto efanayo ne-substrate, noma ingaba yinto ehlukile (efanayo) epitaxy noma heteroepitaxy). Ngenxa yokuthi ungqimba olusha lwekristalu olulodwa luyanda futhi lukhula ngokwesigaba sekristalu se-substrate, lubizwa ngokuthi ungqimba lwe-epitaxial (ubukhulu buvame ukuba ngama-micron ambalwa, uma sithatha i-silicon njengesibonelo: incazelo yokukhula kwe-silicon epitaxial ikwi-substrate yekristalu eyodwa ye-silicon enokuqondisa okuthile kwekristalu. Ungqimba lwekristalu olunobuqotho obuhle besakhiwo se-lattice kanye nokumelana okuhlukile kanye nobukhulu obunokuqondisa okufanayo kwekristalu njenge-substrate ekhuliswe), kanti i-substrate enengqimba ye-epitaxial ibizwa ngokuthi i-epitaxial wafer (epitaxial wafer = ungqimba lwe-epitaxial + substrate). Lapho idivayisi yenziwe kungqimba lwe-epitaxial, ibizwa ngokuthi i-positive epitaxy. Uma idivayisi yenziwe ku-substrate, ibizwa ngokuthi i-reverse epitaxy. Ngalesi sikhathi, ungqimba lwe-epitaxial ludlala indima esekelayo kuphela.

I-wafer epholishiwe

Izindlela zokukhula kwe-Epitaxial

I-epitaxy ye-molecular beam (MBE): Iwubuchwepheshe bokukhula kwe-epitaxial ye-semiconductor okwenziwa ngaphansi kwezimo ze-vacuum eziphezulu kakhulu. Kule ndlela, izinto zomthombo ziyahwamuka ngesimo somsebe wama-athomu noma ama-molecule bese zifakwa ku-substrate ekristalu. I-MBE iwubuchwepheshe bokukhula kwefilimu encane ye-semiconductor obunembile kakhulu futhi obulawulwayo obungalawula ngokunembile ukujiya kwezinto ezibekwe ezingeni le-athomu.
I-Metal organic CVD (MOCVD): Enqubweni ye-MOCVD, igesi ye-organic metal kanye ne-hydride gas N equkethe izakhi ezidingekayo inikezwa ku-substrate ekushiseni okufanele, ibhekane nokusabela kwamakhemikhali ukuze ikhiqize izinto ze-semiconductor ezidingekayo, bese ifakwa ku-substrate, kuyilapho ama-compounds asele kanye nemikhiqizo yokusabela ikhishwa.
I-vapor phase epitaxy (VPE): I-vapor phase epitaxy ubuchwepheshe obubalulekile obuvame ukusetshenziswa ekukhiqizweni kwamadivayisi e-semiconductor. Isimiso esiyisisekelo ukuthutha umusi wezinto eziyisisekelo noma ama-compounds kugesi ethwalayo, bese ubeka amakristalu ku-substrate ngokusebenzisa ukusabela kwamakhemikhali.

Yiziphi izinkinga ezixazululwa yinqubo ye-epitaxy?

Izinto zekristalu eyodwa kuphela ezingakwazi ukuhlangabezana nezidingo ezikhulayo zokukhiqiza amadivayisi ahlukahlukene e-semiconductor. Ngakho-ke, ukukhula kwe-epitaxial, ubuchwepheshe bokukhula kwezinto zekristalu eyodwa obunezingqimba ezincane, kwasungulwa ekupheleni kuka-1959. Ngakho-ke yimuphi umnikelo oqondile ubuchwepheshe be-epitaxy obunawo ekuthuthukisweni kwezinto?

Ku-silicon, lapho ubuchwepheshe bokukhula kwe-silicon epitaxial buqala, kwakuyisikhathi esinzima ngempela ekukhiqizweni kwama-transistors e-silicon anemvamisa ephezulu kanye namandla aphezulu. Ngokombono wezimiso ze-transistor, ukuze kutholakale imvamisa ephezulu kanye namandla aphezulu, i-voltage yokuqhekeka kwendawo yokuqoqa kumele ibe phezulu futhi ukumelana nochungechunge kumele kube kuncane, okungukuthi, ukwehla kwe-voltage yokugcwala kumele kube kuncane. Okokuqala kudinga ukuthi ukumelana kwezinto endaweni yokuqoqa kufanele kube phezulu, kanti okwesibili kudinga ukuthi ukumelana kwezinto endaweni yokuqoqa kufanele kube kuphansi. Izifundazwe ezimbili ziyaphikisana. Uma ubukhulu bezinto endaweni yokuqoqa buncishisiwe ukuze kuncishiswe ukumelana nochungechunge, i-silicon wafer izoba mncane kakhulu futhi ibe buthakathaka ukuthi ingacutshungulwa. Uma ukumelana kwezinto kuncishisiwe, kuzophikisana nesidingo sokuqala. Kodwa-ke, ukuthuthukiswa kobuchwepheshe be-epitaxial kuphumelele.

Isixazululo: Khulisa ungqimba lwe-epitaxial olumelana nokumelana okuphezulu ku-substrate emelana nokumelana okuphansi kakhulu, bese wenza idivayisi ku-epitaxial ungqimba. Lo ngqimba lwe-epitaxial olumelana nokumelana okuphezulu luqinisekisa ukuthi ithubhu line-voltage ephezulu yokuqhekeka, kuyilapho i-substrate emelana nokumelana okuphansi Iphinde inciphise ukumelana kwe-substrate, ngaleyo ndlela inciphise ukwehla kwe-voltage yokugcwala, ngaleyo ndlela ixazulule ukungqubuzana phakathi kwalokhu okubili.

Ngaphezu kwalokho, ubuchwepheshe be-epitaxy njenge-vapor phase epitaxy kanye ne-liquid phase epitaxy ye-GaAs kanye nezinye izinto ze-III-V, II-VI kanye nezinye izinto ze-molecular compound semiconductor nazo zithuthukiswe kakhulu futhi seziyisisekelo samadivayisi amaningi e-microwave, amadivayisi e-optoelectronic, amandla. Kuwubuchwepheshe benqubo obubalulekile ekukhiqizweni kwamadivayisi, ikakhulukazi ukusetshenziswa ngempumelelo kobuchwepheshe be-molecule be-bio kanye ne-metal organic vapor phase epitaxy ezingqimbeni ezincane, ama-superlattice, ama-quantum wells, ama-superlattice acindezelwe, kanye ne-atomic-level thin-layer epitaxy, okuyisinyathelo esisha ocwaningweni lwe-semiconductor. Ukuthuthukiswa "kobunjiniyela bebhande lamandla" emkhakheni kubeke isisekelo esiqinile.

Ezisetshenzisweni ezisebenzayo, amadivayisi e-semiconductor e-wide bandgap cishe ahlala enziwa kungqimba lwe-epitaxial, kanti i-silicon carbide wafer ngokwayo isebenza kuphela njenge-substrate. Ngakho-ke, ukulawulwa kwengqimba ye-epitaxial kuyingxenye ebalulekile embonini ye-wide bandgap semiconductor.

Amakhono ayi-7 amakhulu kubuchwepheshe be-epitaxy

1. Izingqimba ze-epitaxial ezimelana nokumelana okuphezulu (okuphansi) zingatshalwa nge-epitaxial ezindaweni ezimelana nokumelana okuphezulu (okuphezulu).
2. Ingqimba ye-epitaxial yohlobo lwe-N (P) ingakhuliswa nge-epitaxial ku-substrate yohlobo lwe-P (N) ukuze kwakheke i-PN junction ngqo. Ayikho inkinga yokukhokha uma usebenzisa indlela yokusabalalisa ukwenza i-PN junction ku-substrate eyodwa yekristalu.
3. Kuhlanganiswe nobuchwepheshe bemaski, ukukhula kwe-epitaxial okukhethayo kwenziwa ezindaweni ezikhethiwe, okudala izimo zokukhiqizwa kwamasekethe ahlanganisiwe namadivayisi anezakhiwo ezikhethekile.
4. Uhlobo kanye nokuhlushwa kwe-doping kungashintshwa ngokuya ngezidingo ngesikhathi senqubo yokukhula kwe-epitaxial. Ushintsho ekuhlushweni kungaba ushintsho oluzumayo noma ushintsho oluhamba kancane.
5. Ingakhula izakhi ezingafani, ezinezingqimba eziningi, ezinezakhi eziningi kanye nezendlalelo ezincane kakhulu ezinezakhi eziguquguqukayo.
6. Ukukhula kwe-epitaxial kungenziwa ekushiseni okuphansi kunephuzu lokuncibilika kwezinto, izinga lokukhula lingalawuleka, futhi ukukhula kwe-epitaxial kobukhulu bezinga le-athomu kungafinyelelwa.
7. Ingakhulisa izinto zekristalu eyodwa ezingenakudonswa, njenge-GaN, izendlalelo zekristalu eyodwa zamakhemikhali e-tertiary kanye ne-quaternary, njll.