The microstructure of polymer-derived amorphous silicon carbide layers

In this work we present studies on the structure of the layers and of bulk material, which were carried out by XRD, MAS NMR and Raman spectroscopy, depending on pyrolysis conditions. Following results were obtained: Both, silicon carbide layers and bulk material, pyrolysed at 800 °C, were amorphous. Increase of the temperature to 1200 °C leads to a partial amorphous-to-crystalline transition forming β-SiC. Moreover, derivations from stoichiometric SiC were observed: Free silicon was found in thin layers, whereas crystallites of graphite were detected in the bulk material. The amount of excess carbon can be influenced by addition of hydrogen to the pyrolysis atmosphere.