SYNTHESIS OF SILICON-CARBIDE THIN-FILMS WITH POLYCARBOSILANE (PCS)

Polycarbosilane (PCS) thin films were deposited on silicon (and other) substrates and heat treated under vacuum (similar to 10(-6) torr) at temperatures in the range of 200 degrees-1200 degrees C. At temperatur es in the range of 1000 degrees-1200 degrees C, the initially amorphou s PCS films transformed to polycrystalline beta-silicon carbide (beta- SiC). Although PCS films could be deposited at thickness up to 2 mu m, the films with thicknesses >1 mu m could not be transformed to SiC wi thout extensive cracking, The resulting SiC coatings were characterize d using Fourier transform infrared spectroscopy, glancing-angle X-ray diffractometry, secondary-ion mass spectroscopy, Raman spectoscopy, tr ansmission electron microscopy, and scanning electron microscopy. The temperature and time dependence of the amorphous-to-crystalline transi tion could be associated with the evolution of free carbon, oxygen, an d hydrogen in the films.