MAPPING OF ELNES ON A NANOMETER-SCALE BY ELECTRON SPECTROSCOPIC IMAGING

The amorphous interfacial layer between Si substrates, and diamond fil ms grown by plasma-assisted chemical vapour deposition has been studie d by electron spectroscopic imaging. The amorphous layer consists main ly of carbon, which can only be distinguished from the diamond film by analysis of the near-edge structure (ELNES) of the carbon K edge. Ser ies of electron spectroscopic images were acquired across the carbon K edge and were analysed in order to reveal the presence of the pi- an d sigma-excitations. After background removal from the corresponding images, phase maps for the distribution of sp(2) and sp(3) hybridized carbon can be obtained. From the whole series of images, electron, ene rgy-loss spectra can be extracted for any given area in the images. Th e results show that the amorphous layer covers large areas along the i nterface and that regions with only 1-2 nm layer thickness can clearly be analysed. The results obtained with the electron spectroscopic ima ging technique will be compared with results obtained on a field emiss ion gun scanning transmission electron microscope. .