Ukugeleza kwenqubo ye-semiconductor

Ungakuqonda noma ungakaze ufunde i-physics noma izibalo, kodwa ilula kakhulu futhi ifanele abaqalayo. Uma ufuna ukwazi okwengeziwe nge-CMOS, kufanele ufunde okuqukethwe kwalolu daba, ngoba kuphela ngemva kokuqonda ukugeleza kwenqubo (okungukuthi, inqubo yokukhiqiza ye-diode) ungaqhubeka nokuqonda okuqukethwe okulandelayo. Khona-ke ake sifunde ukuthi le CMOS ikhiqizwa kanjani enkampanini esungulwe kulolu daba (kuthatha inqubo engathuthuki njengesibonelo, i-CMOS yenqubo ethuthukisiwe ihlukile ngesakhiwo kanye nesimiso sokukhiqiza).

Okokuqala, kufanele wazi ukuthi ama-wafers atholwa yi-Foundry kumphakeli (isicwecwana se-siliconumphakeli) ngamunye ngamunye, anendawo engaba ngu-200mm (8-intshiimboni) noma 300mm (12-intshiifektri). Njengoba kuboniswe esithombeni esingezansi, empeleni kufana nekhekhe elikhulu, esiyibiza ngokuthi i-substrate.

Nokho, akulula ngathi ukukubheka ngale ndlela. Sibheka ukusuka phansi kuya phezulu futhi sibheke umbono we-cross-sectional, okuba isibalo esilandelayo.

Okulandelayo, ake sibone ukuthi imodeli ye-CMOS ivela kanjani. Njengoba inqubo yangempela idinga izinkulungwane zezinyathelo, ngizokhuluma ngezinyathelo eziyinhloko ze-wafer elula engu-8-intshi lapha.

 

 

Ukwenza kahle kanye ne-Inversion Layer:

Okusho ukuthi, umthombo utshalwa ku-substrate ngokufakwa kwe-ion (I-Ion Implantation, kamuva ebizwa ngokuthi imp). Uma ufuna ukwenza i-NMOS, udinga ukutshala imithombo yohlobo lwe-P. Uma ufuna ukwenza i-PMOS, udinga ukutshala imithombo yohlobo lwe-N. Ukuze kube lula kuwe, ake sithathe i-NMOS njengesibonelo. Umshini wokufakelwa kwe-ion ufaka izakhi zohlobo lwe-P ukuthi zifakwe ku-substrate ekujuleni okuthile, bese uzifudumeza ekushiseni okuphezulu kushubhu yesithando somlilo ukuze wenze la ma-ion asebenze futhi awasabalalise nxazonke. Lokhu kuqeda ukukhiqizwa komthombo. Yile ndlela ebukeka ngayo ngemva kokuqedwa kokukhiqizwa.

Ngemva kokwenza umthombo, kunezinye izinyathelo zokufakelwa kwe-ion, inhloso yazo ukulawula ubukhulu besiteshi samanje kanye ne-threshold voltage. Wonke umuntu angakubiza ngesendlalelo sokuguqula. Uma ufuna ukwenza i-NMOS, ungqimba oluguquguqukayo lufakwe ngama-ion ohlobo lwe-P, futhi uma ufuna ukwenza i-PMOS, isendlalelo sokuguqula sifakwe ngama-ion ohlobo lwe-N. Ngemva kokufakelwa, kuba imodeli elandelayo.

Kuningi okuqukethwe lapha, njengamandla, i-engeli, ukugxilwa kwe-ion ngesikhathi sokufakelwa kwe-ion, njll., okungafakiwe kulolu daba, futhi ngikholelwa ukuthi uma uzazi lezo zinto, kufanele ube umuntu wangaphakathi, futhi kumele abe nendlela yokuwafunda.

 

Ukwenza i-SiO2:

I-Silicon dioxide (i-SiO2, kamuva ebizwa ngokuthi i-oxide) izokwenziwa kamuva. Enqubweni yokukhiqiza ye-CMOS, ziningi izindlela zokwenza i-oxide. Lapha, i-SiO2 isetshenziswa ngaphansi kwesango, futhi ubukhulu bayo buthinta ngokuqondile ubukhulu be-threshold voltage kanye nobukhulu besiteshi samanje. Ngakho-ke, abasunguli abaningi bakhetha indlela ye-oxidation yeshubhu yomlilo enekhwalithi ephezulu kakhulu, ukulawula ukushuba okunembe kakhulu, kanye nokufana okuhle kakhulu kulesi sinyathelo. Eqinisweni, kulula kakhulu, okungukuthi, ku-tube yesithando somlilo nge-oksijeni, izinga lokushisa eliphezulu lisetshenziselwa ukuvumela umoya-mpilo ne-silicon ukuba zisabele ngamakhemikhali ukuze zikhiqize i-SiO2. Ngale ndlela, ungqimba oluncane lwe-SiO2 lukhiqizwa ebusweni buka-Si, njengoba kuboniswe esithombeni esingezansi.

Yebo, kukhona nolwazi oluningi oluqondile lapha, njengokuthi mangaki amadigri adingekayo, ukuthi kungakanani ukugxiliswa komoyampilo okudingekayo, ukuthi izinga lokushisa eliphezulu lidingeka isikhathi esingakanani, njll. Lokhu akukona esikucabangela manje, lezo kucace kakhulu.

Ukwakhiwa kwe-gate end Poly:

Kodwa akukapheli. I-SiO2 ivele ilingane nentambo, futhi isango langempela (i-Poly) alikaqali okwamanje. Ngakho-ke isinyathelo sethu esilandelayo ukubeka ungqimba lwe-polysilicon ku-SiO2 (i-polysilicon nayo yakhiwe ngento eyodwa ye-silicon, kodwa ukuhlelwa kwe-lattice kuhlukile. Ungangibuzi ukuthi kungani i-substrate isebenzisa i-silicon eyodwa yekristalu futhi isango lisebenzisa i-polysilicon. Lapho yincwadi ebizwa ngokuthi iSemiconductor Physics Ungafunda ngayo Kuyaphoxa. I-Poly futhi iyisixhumanisi esibucayi kakhulu ku-CMOS, kodwa ingxenye ye-poly i-Si, futhi ayikwazi ukukhiqizwa ngokusabela okuqondile nge-Si substrate njengokukhula kwe-SiO2. Lokhu kudinga i-CVD yenganekwane (Chemical Vapor Deposition), okuwukusabela ngamakhemikhali ku-vacuum futhi kushelele into ekhiqiziwe ku-wafer. Kulesi sibonelo, into ekhiqiziwe i-polysilicon, bese iwa phezu kwe-wafer (lapha kufanele ngisho ukuthi i-poly ikhiqizwa ku-tube yesithando somlilo nge-CVD, ngakho-ke ukukhiqizwa kwe-poly akwenziwa umshini we-CVD ohlanzekile).

Kodwa i-polysilicon eyakhiwe ngale ndlela izokwenyuka kuyo yonke i-wafer, futhi ibukeka kanjena ngemva kwemvula.

 

Ukuvezwa kwe-Poly ne-SiO2:

Kulesi sinyathelo, isakhiwo esime mpo esisifunayo senziwe ngempela, sine-poly phezulu, i-SiO2 ngezansi, kanye ne-substrate phansi. Kodwa manje yonke i-wafer ifana nalokhu, futhi sidinga kuphela isikhundla esithile ukuze sibe isakhiwo "sompompo". Ngakho kunesinyathelo esibaluleke kakhulu kuyo yonke inqubo - ukuchayeka.
Siqala ukusabalalisa ungqimba lwe-photoresist ebusweni be-wafer, futhi iba kanje.

Bese ubeka imaski echaziwe (iphethini yesifunda ichazwe kumaski) kuyo, futhi ekugcineni uyikhanyise ngokukhanya kwe-wavelength ethile. I-photoresist izosebenza endaweni ene-radiated. Njengoba indawo evinjwe imaski ingakhanyiswa umthombo wokukhanya, lolu cezu lwe-photoresist aluvulwanga lusebenze.

Njengoba i-photoresist ecushiwe kulula kakhulu ukugezwa uketshezi oluthile lwekhemikhali, kuyilapho i-photoresist engacushiwe ayikwazi ukugezwa, ngemva kokushiswa kwemisebe, kusetshenziselwa uketshezi oluthile ukugeza i-photoresist ecushiwe, futhi ekugcineni iba kanje, ishiya i-photoresist lapho i-Poly ne-SiO2 idinga ukugcinwa, futhi isusa i-photoresist lapho ingadingi ukugcinwa khona.