Stress reduction and bond stability during thermal annealing of tetrahedral amorphous carbon

A comprehensive study of the stress release and structural changes caused b y postdeposition thermal annealing of tetrahedral amorphous carbon (ta-C) o n Si has been carried out. Complete stress relief occurs at 600-700 degrees C and is accompanied by minimal structural modifications, as indicated by electron energy loss spectroscopy, Raman spectroscopy, and optical gap meas urements. Further annealing in vacuum converts sp(3) sites to sp(2) with a drastic change occurring after 1100 degrees C. The field emitting behavior is substantially retained up to the complete stress relief, confirming that ta-C is a robust emitting material. (C) 1999 American Institute of Physics . [S0021-8979(99)05910-1].