Preparation of SiC thin film from polyamic acid by the reaction with SiO gas and its shape and property control

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Preparation method : Polyamic acid (PAA) solution was obtained by reacting pyromellitic dianhydride with equimolar aromatic diamine, 4, 4' -oxydianiline, cast on a glass plate, and then imidized. Polyimide film obtained was removed from the plate and was reacted with SiO gas for 1 hour under Argon or in vacuo. By this method, beta-SiC was formed depending on thickness of the starting film, reaction time and heat treatment temperature after imidization. In the case of 8 μm thickness polyimide film, the film was silicidized completely.Shape control : PAA solution was painted on several substrates with different shapes and was reacted with SiO gas to prepare SiC with controlled shape. Due to the stress caused by shrinkage during imidization, polyimide film obtained was broken. Therefore, although shape of the SiC obtained succeed the shape of the carbon source, we can't obtained desired SiC with controlled shape.Property control : By adding boron or lanthanum during PAA preparation, we could obtained foreign element bearing polyimide. By reacting foreign element bearing polyimide film with SiO gas, we also could obtained foreign element bearing SiC film. Electrical resistivity of lanthanum bearing SiC film increases with an increase of temperature up to 400℃.