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 angasebenzi, futhi ibone kalula ukulawulwa kwe-electron ye-valence yezinto zokwakha Kusukela umkhonto et al. Okokuqala 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)
Ngokuya ngokushisa 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 kokucindezela komkhathi (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 isetshenziselwa ukukhishwa kwamandla 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
Isikhathi sokuthumela: Apr-07-2021