Kungani sidinga ukwenza i-epitaxy kuma-silicon wafer substrates?

Ochungechungeni lwemboni ye-semiconductor, ikakhulukazi kuchungechunge lwezimboni ze-semiconductor yesizukulwane sesithathu (i-wide bandgap semiconductor), kukhona ama-substrates kanyei-epitaxializendlalelo. Kuyini ukubaluleka kwe-i-epitaxialungqimba? Uyini umehluko phakathi kwe-substrate ne-substrate?

I-substrate iyi-aisilucwecwanaeyenziwe nge-semiconductor single crystal materials. I-substrate ingangena ngokuqondileisilucwecwanaisixhumanisi sokukhiqiza ukukhiqiza amadivaysi e-semiconductor, noma singasetshenzwa yii-epitaxialinqubo yokukhiqiza ama-wafers e-epitaxial. I-substrate ingaphansi kwe-substrateisilucwecwana(sika isinkwa esilucwecwana, ungathola ukufa okukodwa ngemva kokunye, bese usipakisha ukuze sibe i-chip edumile) (eqinisweni, phansi kwe-chip ngokuvamile kuhlanganiswe ungqimba lwegolide elingemuva, elisetshenziswa njengokuxhumana "nomhlabathi", kodwa yenziwa ngenqubo yangemuva), futhi isisekelo esithwala wonke umsebenzi wokusekela (i-skyscraper ku-chip yakhelwe ku-substrate).

I-Epitaxy isho inqubo yokukhulisa ikristalu entsha ku-crystal substrate eyodwa eye yacutshungulwa ngokucophelela ngokusikwa, ukugaya, ukupholishwa, njll. Ikristalu eyodwa entsha ingaba yinto efanayo ne-substrate, noma ingaba into ehlukile. (i-homoepitaxial noma i-heteroepitaxial).
Njengoba ungqimba olusanda kwakhiwa lwekristalu olulodwa lukhula eduze kwesigaba sekristalu engaphansi, kubizwa ngokuthi ungqimba lwe-epitaxial (imvamisa ugqinsi lwama-microns ambalwa. Thatha i-silicon njengesibonelo: incazelo ye-silicon epitaxial ukukhula ukukhulisa ungqimba lwekristalu enobuqotho besakhiwo se-lattice. ku-silicon single crystal substrate ene-crystal orientation ethile kanye nokumelana okuhlukile nokuqina njenge-substrate), futhi i-substrate ene-epitaxial layer ibizwa ngokuthi i-epitaxial wafer (i-epitaxial wafer = i-epitaxial layer + substrate). Ukukhiqizwa kwedivayisi kwenziwa kungqimba lwe-epitaxial.

I-Epitaxiality ihlukaniswe yaba yi-homoepitaxiality kanye ne-heteroepitaxiality. I-homoepitaxiality iwukukhulisa ungqimba lwe-epitaxial lwento efanayo ne-substrate ku-substrate. Kuyini ukubaluleka kwe-homoepitaxiality? - Thuthukisa ukuzinza nokuthembeka komkhiqizo. Nakuba i-homoepitaxiality iwukukhulisa ungqimba lwe-epitaxial lwento efanayo njenge-substrate, nakuba impahla iyafana, ingathuthukisa ukuhlanzeka kwezinto ezibonakalayo nokufana kwe-wafer surface. Uma kuqhathaniswa namawafa aphucuziwe acutshungulwa ukupholishwa komshini, i-substrate ecutshungulwa nge-epitaxiality inokusitha okuphezulu kwendawo, ukuhlanzeka okuphezulu, ukonakala okuncane okumbalwa, nokungcola okumbalwa kwendawo. Ngakho-ke, i-resistivity ifana kakhulu, futhi kulula ukulawula ukukhubazeka okungaphezulu njengezinhlayiya ezingaphezulu, amaphutha wokupakisha, nokuhlukaniswa. I-Epitaxy ayigcini nje ngokuthuthukisa ukusebenza komkhiqizo, kodwa futhi iqinisekisa ukuzinza nokuthembeka komkhiqizo.
Yiziphi izinzuzo zokwenza olunye ungqimba lwama-athomu e-silicon epitaxial ku-silicon wafer substrate? Kunqubo ye-silicon ye-CMOS, ukukhula kwe-epitaxial (EPI, epitaxial) ku-wafer substrate kuyisinyathelo esibucayi kakhulu.
1. Thuthukisa ikhwalithi yekristalu
Ukukhubazeka kokuqala kwe-substrate nokungcola: I-wafer substrate ingaba nokukhubazeka okuthile nokungcola phakathi nenqubo yokukhiqiza. Ukukhula kongqimba lwe-epitaxial kungakhiqiza ungqimba lwe-silicon yekhwalithi ephezulu, enesici esiphansi kanye nokungcola-okugxilwa kwe-single-crystalline ku-substrate, okubaluleke kakhulu ekukhiqizeni idivayisi elandelayo. Isakhiwo se-crystal esilinganayo: Ukukhula kwe-Epitaxial kungaqinisekisa isakhiwo se-crystal esifana kakhulu, ukunciphisa umthelela wemingcele yokusanhlamvu kanye nokukhubazeka ku-substrate material, futhi ngaleyo ndlela kuthuthukise ikhwalithi ye-crystal ye-wafer yonke.
2. Thuthukisa ukusebenza kukagesi
Lungiselela izici zedivayisi: Ngokukhulisa ungqimba lwe-epitaxial ku-substrate, ukugxiliswa kwe-doping nohlobo lwe-silicon kungalawulwa ngokunembile ukuze kuthuthukiswe ukusebenza kukagesi kwedivayisi. Isibonelo, i-doping ye-epitaxial layer ingalungisa kahle i-threshold voltage namanye amapharamitha kagesi we-MOSFET. Yehlisa ukuvuza kwamanje: Izendlalelo ze-epitaxial zekhwalithi ephezulu zinesici esiphansi, esiza ukunciphisa ukuvuza kwamanje kudivayisi, ngaleyo ndlela kuthuthukiswe ukusebenza nokuthembeka kwedivayisi.
3. Sekela ama-node enqubo ethuthukisiwe
Ukunciphisa usayizi wesici: Kumanodi enqubo amancane (afana ne-7nm, 5nm), usayizi wesici sedivayisi uyaqhubeka nokuncipha, okudinga izinto ezicwengisiswe kakhulu nezinekhwalithi ephezulu. Ubuchwepheshe bokukhula kwe-Epitaxial bungahlangabezana nalezi zidingo futhi busekele ukukhiqizwa kwesekethe edidiyelwe kokusebenza okuphezulu nokuminyana okuphezulu. Thuthukisa i-voltage yokuphuka: Isendlalelo se-epitaxial singaklanywa ukuthi sibe ne-voltage ephezulu yokuphuka, ebalulekile ekukhiqizeni amandla aphezulu kanye namadivayisi anamandla kagesi. Isibonelo, kumadivayisi wamandla, isendlalelo se-epitaxial singakhuphula i-voltage yokuwohloka kwedivayisi futhi sandise ububanzi bokusebenza obuphephile.
4. Ukuhambisana kwenqubo kanye nesakhiwo sezendlalelo eziningi
Isakhiwo se-Multi-layer: Ubuchwepheshe bokukhula kwe-Epitaxial buvumela izakhiwo ezinezingqimba eziningi ukuthi zikhule ku-substrate, futhi izendlalelo ezihlukene zingaba nokugxilwa kwe-doping nezinhlobo ezahlukene. Lokhu kusiza kakhulu ekwenzeni amadivaysi e-CMOS ayinkimbinkimbi kanye nokuzuza ukuhlanganiswa kwezinhlangothi ezintathu. Ukuhambisana: Inqubo yokukhula kwe-epitaxial ihambisana kakhulu nezinqubo zokukhiqiza ze-CMOS ezikhona futhi ingahlanganiswa kalula nezinqubo ezikhona zokukhiqiza ngaphandle kokuguqula kakhulu imigqa yenqubo.