SEARCH FOR CARBON NITRIDE CNX COMPOUNDS WITH A HIGH-NITROGEN CONTENT BY ELECTRON-CYCLOTRON-RESONANCE PLASMA DEPOSITION

In order to synthesize and characterize the hypothetically hard compou nd C3N4, we used an ultrahigh-vacuum-compatible electron cyclotron res onance plasma source and an in-situ X-ray photoemission spectroscopy ( XPS) technique analysis. An N-2 plasma has been used to excite a hydro carbon gas (CH4) in the vicinity of an Si substrate maintained at a te mperature T-S. High-nitrogen-containing CNx:H (x greater than or equal to 1) coatings have been synthesized for the first time on substrates held at room temperature. However, binding energy analysis of the XPS C 1s and N 1s core level lines revealed a variety of local environmen ts (single and double C-N bonds, in addition to hydrogenated groups) n on-compatible with C3N4. Annealing of samples deposited at room temper ature and attempts to synthesize the material at a high substrate temp erature (above 500 degrees C) or by nitrogen bombardment of amorphous carbon evidenced the high thermal instability of the C-N bonds and led generally to a nitridation process limited to the surface of the Si s ubstrate.