CVD mai zafi shine hanya ta farko kuma mafi shahara ta girma lu'u-lu'u a ƙarancin matsin lamba. 1982 Matsumoto et al. sun dumama filament na ƙarfe mai jurewa zuwa sama da 2000°C, wanda zafin jiki na iskar H2 da ke ratsa filament ɗin ke samar da atom ɗin hydrogen cikin sauƙi. Samar da hydrogen na atomic a lokacin pyrolysis na hydrocarbon ya ƙara yawan ajiyar fina-finan lu'u-lu'u. Ana ajiye lu'u-lu'u a zaɓi kuma ana hana samuwar graphite, wanda ke haifar da ƙimar ajiyar fim ɗin lu'u-lu'u akan tsari na mm/h, wanda shine babban ƙimar ajiyar bayanai ga hanyoyin da aka saba amfani da su a masana'antu. Ana iya yin HFCVD ta amfani da nau'ikan tushen carbon iri-iri, kamar methane, propane, acetylene, da sauran hydrocarbons, har ma da wasu hydrocarbons masu ɗauke da oxygen, kamar acetone, ethanol, da methanol. Ƙara ƙungiyoyi masu ɗauke da oxygen yana faɗaɗa kewayon zafin jiki don ajiyar lu'u-lu'u.
Baya ga tsarin HFCVD na yau da kullun, akwai sauye-sauye da dama ga tsarin HFCVD. Mafi yawansu shine haɗin plasma na DC da tsarin HFCVD. A cikin wannan tsarin, ana iya amfani da ƙarfin bias ga substrate da filament. Bias mai kyau koyaushe akan substrate da wani mummunan bias akan filament yana sa electrons su yi ruwan sama a kan substrate, wanda ke ba da damar hydrogen na saman ya ɓace. Sakamakon desorption shine ƙaruwa a cikin adadin ajiyar fim ɗin lu'u-lu'u (kimanin 10 mm/h), wata dabara da aka sani da HFCVD mai taimakawa electron. lokacin da ƙarfin bias ya isa ya haifar da kwararar plasma mai ƙarfi, rugujewar H2 da hydrocarbons yana ƙaruwa sosai, wanda a ƙarshe yana haifar da ƙaruwar yawan girma. Lokacin da polarity na bias ya juya (ƙasa yana da mummunan bias), fashewar ion yana faruwa akan substrate, wanda ke haifar da ƙaruwar nucleation na lu'u-lu'u akan substrates marasa lu'u-lu'u. Wani gyara kuma shine maye gurbin zare mai zafi guda ɗaya da zare daban-daban domin cimma daidaiton wurin ajiya da kuma babban yanki na zare mai lu'u-lu'u. Rashin kyawun HFCVD shine cewa ƙafewar zafi na zare na iya haifar da gurɓatawa a cikin zaren lu'u-lu'u.
(2) Microwave Plasma CVD (MWCD)
A shekarun 1970, masana kimiyya sun gano cewa yawan sinadarin hydrogen na atom zai iya ƙaruwa ta amfani da sinadarin DC. Sakamakon haka, sinadarin plasma ya zama wata hanya ta haɓaka samuwar fina-finan lu'u-lu'u ta hanyar wargaza H2 zuwa sinadarin hydrogen na atom da kuma kunna ƙungiyoyin atom na carbon. Baya ga sinadarin DC, wasu nau'ikan plasma guda biyu suma sun sami kulawa. Tsarin plasma na microwave CVD yana da mitar motsawa ta 2.45 GHZ, kuma tsarin plasma na RF CVD yana da mitar motsawa ta 13.56 MHz. Tsarin plasma na microwave na musamman ne saboda mitar microwave yana haifar da girgizar electron. Lokacin da electrons suka yi karo da kwayoyin iskar gas ko kwayoyin halitta, ana samar da babban adadin rabuwar. Ana kiran plasma na microwave sau da yawa a matsayin abu tare da electrons "zafi", ions "sanyi" da barbashi masu tsaka tsaki. A lokacin da aka ajiye fim mai siriri, microwaves suna shiga ɗakin haɗa CVD da aka inganta ta plasma ta taga. Plasma mai haske gabaɗaya siffarsa mai siffar ƙwallo ce, kuma girman spherical yana ƙaruwa da ƙarfin microwave. Ana shuka siraran furannin lu'u-lu'u a kan wani abu da ke kusurwar yankin mai haske, kuma ba dole ba ne substrate ya kasance yana hulɗa kai tsaye da yankin mai haske.
– An fitar da wannan labarin ne dagainjin shafa injin injinGuangdong Zhenhua
Lokacin Saƙo: Yuni-19-2024