25 KB118 KB23 KB200020242011Cvelbar, Urošštevilka:3letnik:45str. 179-183ISSN:1580-2949COBISSID:857514URN:URN:NBN:SI:doc-ZBWZUA4LenInštitut za kovinske materiale in tehnologijeMateriali in tehnologijeAugerjeva spektroskopijahidrogeniranjekisikmetanogljikplazmaRemoval of a thin hydrogenated carbon film by oxygen plasma treatment| Odstranjevanje tanke plasti hidrogeniranega ogljika s kisikovo plazmo|Capability of low pressure oxygen as a medium for removal of hydrogenated carbon thin films is demonstrated. The film was deposited onto polished iron discs by CVD method. Discs were mounted into a discharge chamber which was evacuated to the ultimate pressure of about 5 Pa. Methane of commercial puritywas leaked into the chamber during continuous pumping so the pressure of 100 Pa was established. Weakly ionized plasma was then created in the chamber by an inductively coupled RF generator operating at the frequency of 27.12 MHz and the power of about 200 W. The methane molecules dissociated in the plasma forming CHx radicals that adsorbed on the sample surface causing formation of a thin film of hydrogenated carbon. AES depth profiling showed that a 3 nm thick film was formed after 200 s of plasma treatment. Samples were then exposed to oxygen plasma in the same chamber, and characterized by AES as well as water drop contact angle. After 12 s of oxygen plasma treatmentthe samples were visually free of carbon and the AES depth profiling proved it. The contact angle of a water drop decreased from initial 80° to about 10° indicating a rapid transformation of the surface properties from hydrophobic to hydrophilic character. The experiments allowed for estimation of the cleaning efficiency which was about 0.25 nm/sPrispevek opisuje možnosti, ki jih daje kisikova plazma pri odstranjevanju tankih plasti hidrogeniranega ogljika. Plasti so bile pripravljene na železnih poliranih vzorcih z nanosom iz parne faze. Vzorci so bili postavljeni v razelektritveno posodo vakuumskega sistema. Sistem je bil najprej izčrpan dokončnega tlaka okoli 5 Pa, potem pa smo ob stalnem črpanju dovajali metan pri tlaku 100 Pa. V metanu smo ustvarili plinsko plazmo z razelektritvijo, ki smo jo vzbujali z radiofrekvenčnim generatorjem moči okoli 200 W in frekvence 27,12 MHz. Molekule metana v plazmi disociirajo, nastali radikali CHx pa se lahko vežejo na površino vzorca in počasi tvorijo tanko plast hidrogeniranega ogljika. Profilna analiza s spektroskopijo Augerjevih elektronov (AES) je pokazala, da je po 200 s obdelave nastala plast debeline okoli 3 nm. Vzorci sobili potem izpostavljeni delovanju kisikove plazme v istem rektorju. Po izpostavitvi so bili analizirani z AES, izmerili pa smo tudi kontaktne kote vodnih kapljic v odvisnosti od časa izpostavitve kisikovi plazmi. Globinski profili AES so pokazali izredno veliko stopnjo čistosti vzorcev po okoli 12-sekundni obdelavi. Kontaktni kot vodne kapljice je bil sprva 80°, kar kaže na hidrofobnost plasti hidrogeniranega ogljika, že po 1 s obdelave s kisikovo plazmo pa se je zmanjšal na okoli 10°, kar kaže na hitro funkcionalizacijo s polarnimi skupinami. Rezultati raziskav so omogočili izračun hitrosti jedkanja, ki je za navedene vzorce okoli 0,25 nm/sTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaInštitut za kovinske materiale in tehnologije