1. Njira zazikulu za plasma zowonjezera mpweya wamankhwala
Plasma enhanced chemical vapor deposition (PECVD) ndi ukadaulo watsopano wokulitsa mafilimu opyapyala pogwiritsa ntchito zinthu za gaseous mothandizidwa ndi plasma yotulutsa kuwala. Chifukwa ukadaulo wa PECVD umakonzedwa ndi kutulutsa kwa gasi, mawonekedwe a plasma osalingana amagwiritsidwa ntchito bwino, ndipo njira yoperekera mphamvu yamachitidwe imasinthidwa. Nthawi zambiri, ukadaulo wa PECVD ukagwiritsidwa ntchito pokonzekera makanema owonda, kukula kwa makanema owonda makamaka kumaphatikizapo njira zitatu zotsatirazi.
Choyamba, mu plasma sanali equilibrium, ma elekitironi anachita ndi anachita mpweya mu gawo loyamba kuwola anachita mpweya kupanga osakaniza ayoni ndi yogwira magulu;
Kachiwiri, mitundu yonse yamagulu yogwira ntchito imafalikira ndikuyendetsa pamwamba ndi khoma la filimuyo, ndipo zochitika zachiwiri pakati pa ma reactants zimachitika nthawi imodzi;
Pomaliza, mitundu yonse yazinthu zoyambirira ndi zachiwiri zomwe zimafika pamtunda wakukula zimadyedwa ndikuchitapo kanthu, ndikutulutsanso ma molekyulu a mpweya.
Makamaka, teknoloji ya PECVD yochokera pa njira yowunikira yowunikira imatha kupanga zomwe gasi ionize kupanga madzi a m'magazi pansi pa chisangalalo chamunda wamagetsi akunja. Mu plasma yotulutsa kuwala, mphamvu ya kinetic ya ma elekitironi yofulumizitsidwa ndi gawo lamagetsi lakunja nthawi zambiri imakhala pafupifupi 10ev, kapena kupitilira apo, zomwe zimakwanira kuwononga zomangira zamakemikolo a mamolekyu amafuta amafuta. Chifukwa chake, chifukwa cha kugunda kwamphamvu kwa ma elekitironi amphamvu kwambiri komanso mamolekyu amafuta a gasi, mamolekyu a gasi amapangidwa ndi ionized kapena kuwola kuti apange maatomu osalowerera ndale ndi zinthu zamagulu. Ma ion abwino amafulumizitsidwa ndi gawo la ion lomwe limathamangitsa gawo lamagetsi ndikugundana ndi electrode yapamwamba. Palinso gawo lamagetsi laling'ono la ion laling'ono pafupi ndi electrode yapansi, kotero gawo lapansili limawomberedwanso ndi ma ion pamlingo wina. Chotsatira chake, chinthu chosalowerera ndale chopangidwa ndi kuwonongeka chimafalikira ku khoma la chubu ndi gawo lapansi. M'kati mwa kugwedezeka ndi kufalikira, tinthu tating'onoting'ono ndi magulu (maatomu osalowerera ndale ndi mamolekyu amatchedwa magulu) amakumana ndi ma ion molecule reaction ndi gulu la molekyulu chifukwa cha njira yayifupi yaulere. The mankhwala katundu wa mankhwala yogwira zinthu (makamaka magulu) kuti kufika gawo lapansi ndi adsorbed akugwira ntchito kwambiri, ndipo filimu amapangidwa ndi kugwirizana pakati pawo.
2. Chemical zochita mu plasma
Chifukwa chisangalalo cha momwe gasi pakutulutsa kowala kumakhala kugundana kwa ma elekitironi, zomwe zimachitika mu plasma ndizosiyanasiyana, komanso kulumikizana pakati pa plasma ndi malo olimba kumakhala kovuta kwambiri, zomwe zimapangitsa kuti zikhale zovuta kuphunzira makinawo. Njira ya PECVD. Pakadali pano, machitidwe ambiri ofunikira adakongoletsedwa ndi zoyeserera kuti apeze mafilimu okhala ndi zinthu zabwino. Pakuyika kwamakanema owonda opangidwa ndi silicon kutengera ukadaulo wa PECVD, ngati njira yoyikayo ingawululidwe mozama, kuchuluka kwa mafilimu opangidwa ndi silicon kumatha kukulitsidwa kwambiri pakuwonetsetsa kuti zinthu zili bwino kwambiri.
Pakalipano, mu kafukufuku wa mafilimu owonda kwambiri a silicon, hydrogen diluted silane (SiH4) amagwiritsidwa ntchito kwambiri ngati gasi wamagetsi chifukwa pali kuchuluka kwa haidrojeni m'mafilimu owonda kwambiri a silicon. H amatenga gawo lofunikira kwambiri pamakanema owonda opangidwa ndi silicon. Ikhoza kudzaza zomangira zolendewera muzinthu zakuthupi, kuchepetsa kwambiri mphamvu ya chilema, ndikuzindikira mosavuta kulamulira kwa valence electron ya zipangizo Popeza spear et al. Poyamba anazindikira zotsatira za doping za silicon woonda mafilimu ndipo anakonza choyamba PN mphambano mu, kafukufuku pa kukonzekera ndi kugwiritsa ntchito silicon-based mafilimu woonda kutengera luso PECVD wapangidwa ndi kulumpha ndi malire. Choncho, machitidwe a mankhwala m'mafilimu owonda kwambiri a silicon omwe amaikidwa ndi teknoloji ya PECVD adzafotokozedwa ndikukambidwa m'munsimu.
Pansi pa kutulutsa kowala, chifukwa ma electron mu plasma ya silane ali ndi mphamvu zambiri za EV, H2 ndi SiH4 zidzawola pamene ziwombana ndi ma electron, omwe ali a zomwe zimayambira. Ngati sitiganizira zachisangalalo chapakati, titha kupeza zotsatirazi za sihm (M = 0,1,2,3) ndi 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)
e+H2→2H+e (2.5)
Malinga ndi kutentha kwanthawi zonse kwa kupanga mamolekyu a dziko lapansi, mphamvu zomwe zimafunikira pazigawo zomwe zili pamwambazi (2.1) ~ (2.5) ndi 2.1, 4.1, 4.4, 5.9 EV ndi 4.5 EV motsatana. Ma electron amphamvu kwambiri mu plasma amathanso kukumana ndi zotsatirazi
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)
Mphamvu yofunikira pa (2.6) ~ (2.9) ndi 11.9, 12.3, 13.6 ndi 15.3 EV motsatana. Chifukwa cha kusiyana kwa mphamvu zamachitidwe, kuthekera kwa (2.1) ~ (2.9) kuyankhidwa kumakhala kosagwirizana. Kuphatikiza apo, sihm yopangidwa ndi machitidwe (2.1) ~ (2.5) idzakumana ndi zotsatirazi zotsatirazi kuti ionize, monga
SiH+e→SiH++2e (2.10)
SiH2+e→SiH2++2e (2.11)
SiH3+e→SiH3++2e (2.12)
Ngati zomwe tafotokozazi zikuchitika pogwiritsa ntchito ma elekitironi imodzi, mphamvu yofunikira ndi pafupifupi 12 eV kapena kupitilira apo. Poona kuti chiwerengero cha ma elekitironi amphamvu kwambiri pamwamba pa 10ev mu plasma yofooka ya ionized ndi kachulukidwe ka elekitironi ya 1010cm-3 ndi yaying'ono pansi pa kupanikizika kwamlengalenga (10-100pa) pokonzekera mafilimu opangidwa ndi silicon, The cumulative. mwayi wa ionization nthawi zambiri umakhala wocheperako kuposa mwayi wosangalatsa. Choncho, chiwerengero cha mankhwala omwe ali pamwambawa mu silane plasma ndi ochepa kwambiri, ndipo gulu losalowerera ndale la sihm ndilopambana. Zotsatira za kusanthula kwa misala zimatsimikiziranso izi [8]. Bourquard et al. Komanso adanenanso kuti kuchuluka kwa sihm kunatsika mu dongosolo la sih3, sih2, Si ndi SIH, koma kuchuluka kwa SiH3 kunali katatu kuposa SIH. Robertson ndi al. Adanenedwa kuti muzinthu zopanda ndale za sihm, silane yoyera imagwiritsidwa ntchito makamaka pakutulutsa mphamvu zambiri, pomwe sih3 idagwiritsidwa ntchito makamaka pakutulutsa mphamvu zochepa. Kukonzekera kwa ndende kuchokera pamwamba mpaka pansi kunali SiH3, SiH, Si, SiH2. Choncho, magawo a plasma amakhudza kwambiri mapangidwe a sihm ndale.
Kuphatikiza pa kulekanitsidwa kwapamwambaku ndi machitidwe a ionization, zochitika zachiwiri pakati pa mamolekyu a ionic ndizofunikira kwambiri.
SiH2＋+SiH4→SiH3++SiH3 (2.13)
Chifukwa chake, potengera kuchuluka kwa ion, sih3 + ndiyoposa sih2 +. Ikhoza kufotokoza chifukwa chake pali ma sih3 + ions ambiri kuposa sih2 + ions mu SiH4 plasma.
Kuphatikiza apo, padzakhala kugunda kwa ma atomu a molekyulu momwe maatomu a haidrojeni mu plasma amatenga hydrogen mu SiH4.
H+ SiH4→SiH3+H2 (2.14)
Ndi exothermic anachita ndi kalambulabwalo kwa mapangidwe si2h6. Zoonadi, maguluwa sali pamtunda wokha, komanso amasangalala ndi mkhalidwe wokondwa mu plasma. Kutulutsa kwa silane plasma kukuwonetsa kuti pali maiko osangalatsa a Si, SIH, h, ndi SiH2, SiH3
Nthawi yotumiza: Apr-07-2021