Ubuchwepheshe obuyisisekelo be-plasma enhanced chemical vapor deposition (PECVD)

1. Izinqubo eziyinhloko ze-plasma ezithuthukisa ukufakwa komhwamuko wamakhemikhali

 

I-Plasma enhanced chemical vapor deposition (PECVD) ubuchwepheshe obusha bokukhula kwamafilimu amancanyana ngokusabela kwamakhemikhali ezinto ezinegesi ngosizo lweplasma yokukhipha ukukhanya.Ngenxa yokuthi ubuchwepheshe be-PECVD bulungiswa ngokukhishwa kwegesi, izici zokusabela ze-plasma engalingani zisetshenziswa ngempumelelo, futhi imodi yokuphakela amandla yesistimu yokusabela iguqulwa ngokuyisisekelo.Ngokuvamile, lapho ubuchwepheshe be-PECVD busetshenziselwa ukulungisa amafilimu amancane, ukukhula kwamafilimu amancane ikakhulukazi kuhlanganisa izinqubo ezintathu eziyisisekelo ezilandelayo.

 

Okokuqala, ku-plasma engalingani, ama-electron asabela ngegesi yokusabela esigabeni sokuqala ukubola igesi yokusabela futhi enze ingxube yama-ion namaqembu asebenzayo;

 

Okwesibili, zonke izinhlobo zamaqembu asebenzayo zihlakazeka futhi zithuthelwe phezulu kanye nodonga lwefilimu, futhi ukusabela kwesibili phakathi kwama-reactants kwenzeka ngesikhathi esifanayo;

 

Ekugcineni, zonke izinhlobo zemikhiqizo yokusabela eyinhloko neyesibili efinyelela endaweni yokukhula iyakhangiswa futhi isabela phezulu, ephelezelwa ukukhishwa kabusha kwama-molecule egesi.

 

Ngokuqondile, ubuchwepheshe be-PECVD obusekelwe endleleni yokukhishwa kokukhanya bungenza igesi yokusabela i-ionize yakhe i-plasma ngaphansi kwenjabulo yensimu yangaphandle ye-electromagnetic.Ku-plasma ekhipha ukukhanya, amandla e-kinetic ama-electron asheshiswa inkambu kagesi yangaphandle ngokuvamile angaba ngu-10ev, noma ngisho nangaphezulu, okwanele ukucekela phansi izibopho zamakhemikhali zama-molecule egesi asebenzayo.Ngakho-ke, ngokushayisana kwe-inelastic kwama-electron anamandla amakhulu nama-molecule egesi asebenzayo, ama-molecule egesi azokwenziwa i-ionized noma aboliswe ukuze akhiqize ama-athomu angathathi hlangothi kanye nemikhiqizo yamangqamuzana.Ama-ion amahle asheshiswa ungqimba lwe-ion olusheshisa insimu kagesi futhi angqubuzane ne-electrode ephezulu.Kukhona futhi insimu kagesi encane ye-ion layer eduze kwe-electrode ephansi, ngakho-ke i-substrate iphinde iqhume ngama-ion ngezinga elithile.Ngenxa yalokho, into engathathi hlangothi ekhiqizwa ukubola isakazeka odongeni lweshubhu kanye ne-substrate.Enqubweni yokukhukhuleka nokusabalalisa, lezi zinhlayiya namaqembu (ama-athomu angathathi hlangothi namakhemikhali asebenzayo abizwa ngokuthi amaqembu) azobhekana nokusabela kwe-molecule ye-ion kanye nokusabela kwe-molecule yeqembu ngenxa yendlela emfushane ekhululekile emaphakathi.Izakhiwo zamakhemikhali zamakhemikhali asebenzayo (ikakhulukazi amaqembu) afinyelela ku-substrate futhi adsorbed asebenza kakhulu, futhi ifilimu yakhiwa ukuxhumana phakathi kwabo.

 

2. Ukusabela kwamakhemikhali ku-plasma

 

Ngenxa yokuthi isasasa legesi elisabelayo ohlelweni lokukhishwa kokukhanya ikakhulukazi ukushayisana kwe-electron, ukusabela okuyisisekelo ku-plasma kuhlukahlukene, futhi nokuxhumana phakathi kwe-plasma nendawo eqinile nakho kuyinkimbinkimbi kakhulu, okwenza kube nzima kakhulu ukufunda umshini. yenqubo ye-PECVD.Kuze kube manje, amasistimu amaningi okusabela athuthukisiwe ngokuhlolwa ukuze kutholwe amafilimu anezakhiwo ezifanele.Ukuze kufakwe amafilimu amancane asekelwe ku-silicon asekelwe kubuchwepheshe be-PECVD, uma indlela yokubeka ingadalulwa ngokujulile, izinga lokubekwa kwamafilimu amancane asekelwe ku-silicon lingakhuphuka kakhulu ngesisekelo sokuqinisekisa izakhiwo ezinhle kakhulu ezibonakalayo.

 

Njengamanje, ocwaningweni lwamafilimu amancane asekelwe ku-silicon, i-hydrogen diluted silane (SiH4) isetshenziswa kabanzi njengegesi yokusabela ngoba kunenani elithile le-hydrogen kumafilimu amancane asekelwe ku-silicon.U-H udlala indima ebaluleke kakhulu kumafilimu amancanyana asuselwa ku-silicon.Ingagcwalisa izibopho ezilengayo esakhiweni sezinto ezibonakalayo, inciphise kakhulu izinga lamandla esici, futhi ibone kalula ukulawulwa kwe-electron ye-valence yezinto zokwakha Kusukela umkhonto et al.Kuqale kwaqaphela umphumela we-doping wamafilimu amancanyana e-silicon futhi kwalungiselela ukuhlangana kwe-PN yokuqala, ucwaningo mayelana nokulungiswa kanye nokusetshenziswa kwamafilimu amancanyana asekelwe ku-silicon asekelwe kubuchwepheshe be-PECVD lwenziwe ngokuzumayo nemingcele.Ngakho-ke, ukusabela kwamakhemikhali kumafilimu amancane asekelwe ku-silicon afakwe ubuchwepheshe be-PECVD kuzochazwa futhi kuxoxwe kulokhu okulandelayo.

 

Ngaphansi kwesimo sokukhishwa kokukhanya, ngoba ama-electron ku-plasma ye-silane anamandla angaphezu kwe-EV amaningana, i-H2 ne-SiH4 izobola lapho ishayisana ngama-electron, okuyingxenye yokusabela okuyinhloko.Uma singazicabangeli izimo ezijabulisayo ezimaphakathi, singathola ukusabela okulandelayo kokuhlukaniswa kwe-sihm (M = 0,1,2,3) no-H

 

e+SiH4→SiH2+H2+e (2.1)

 

e+SiH4→SiH3+ H+e (2.2)

 

e+SiH4→Si+2H2+e (2.3)

 

e+SiH4→SiH+H2+H+e (2.4)

 

I-e+H2→2H+e (2.5)

 

Ngokokushisa okujwayelekile kokukhiqizwa kwama-molecule ezwe eliphansi, amandla adingekayo ezinqubweni zokuhlukanisa ezingenhla (2.1) ~ (2.5) angu-2.1, 4.1, 4.4, 5.9 EV kanye no-4.5 EV ngokulandelanayo.Ama-electron aphezulu ku-plasma nawo angabhekana nokusabela kwe-ionization okulandelayo

 

e+SiH4→SiH2++H2+2e (2.6)

 

e+SiH4→SiH3++ H+2e (2.7)

 

e+SiH4→Si++2H2+2e (2.8)

 

e+SiH4→SiH++H2+H+2e (2.9)

 

Amandla adingekayo ku-(2.6) ~ (2.9) yi-11.9, 12.3, 13.6 kanye no-15.3 EV ngokulandelanayo.Ngenxa yomehluko wamandla okusabela, amathuba okuthi (2.1) ~ (2.9) ukusabela awalingani kakhulu.Ngaphezu kwalokho, i-sihm eyakhiwe ngenqubo yokusabela (2.1) ~ (2.5) izobhekana nokusabela okulandelayo okulandelayo ukuze i-ionize, njenge

 

SiH+e→SiH++2e (2.10)

 

SiH2+e→SiH2++2e (2.11)

 

SiH3+e→SiH3++2e (2.12)

 

Uma ukusabela okungenhla kwenziwa ngenqubo ye-electron eyodwa, amandla adingekayo angaba ngu-12 eV noma ngaphezulu.Uma kubhekwa iqiniso lokuthi inani lama-electron anamandla angaphezu kuka-10ev ku-plasma ene-ionized ebuthakathaka ene-electron density engu-1010cm-3 lincane kakhulu ngaphansi kwengcindezi yomkhathi (10-100pa) ukulungiselela amafilimu asekelwe ku-silicon, The cumulative Amathuba e-ionization ngokuvamile mancane kunamathuba esasasa.Ngakho-ke, ingxenye yalezi zinhlanganisela ezingenhla ze-ionized ku-plasma ye-silane incane kakhulu, futhi iqembu elingathathi hlangothi le-sihm livelele.Imiphumela yokuhlaziywa kwe-mass spectrum nayo ifakazela lesi siphetho [8].Bourquard et al.Uphinde waveza ukuthi ukugxilwa kwe-sihm kwehle ngohlelo lwe-sih3, sih2, Si kanye ne-SIH, kodwa ukugxiliswa kwe-SiH3 okungenani kwakuphindwe kathathu kune-SIH.Robertson et al.Kubikwe ukuthi emikhiqizweni engathathi hlangothi ye-sihm, i-silane ehlanzekile yayisetshenziselwa ngokuyinhloko ukukhipha amandla aphezulu, kuyilapho i-sih3 yayisetshenziselwa ngokuyinhloko ukukhipha amandla aphansi.Ukuhleleka kokugxilisa ingqondo kusuka phezulu kuye phansi kwakuyi-SiH3, SiH, Si, SiH2.Ngakho-ke, imingcele yenqubo ye-plasma ithinta kakhulu ukwakheka kwemikhiqizo engathathi hlangothi ye-sihm.

 

Ngaphezu kokuhlukana okungenhla kanye nokusabela kwe-ionization, ukusabela kwesibili phakathi kwama-molecule e-ionic nakho kubaluleke kakhulu.

 

SiH2++SiH4→SiH3++SiH3 (2.13)

 

Ngakho-ke, ngokuya nge-ion concentration, i-sih3 + ingaphezu kwe-sih2 +.Ingachaza ukuthi kungani kukhona ama-sih3 + ions amaningi kune-sih2 + ions ku-plasma ye-SiH4.

 

Ngaphezu kwalokho, kuzoba khona ukungqubuzana kwe-athomu yamangqamuzana lapho ama-athomu e-hydrogen ku-plasma ethatha i-hydrogen ku-SiH4.

 

H+ SiH4→SiH3+H2 (2.14)

 

Iwukusabela kwe-exothermic kanye nesandulela sokwakheka kwe-si2h6.Yiqiniso, lawa maqembu awekho kuphela esimweni esingaphansi, kodwa futhi ajabule esimweni esijabulisayo ku-plasma.I-spectra ekhishwayo ye-silane plasma ibonisa ukuthi kunezimo ezijabulisayo ze-Si, SIH, h, kanye nezimo zokudlidliza ze-SiH2, SiH3

I-Silicon Carbide Coating (16)


Isikhathi sokuthumela: Apr-07-2021
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