Spectro-microscopy of ultra-thin SiN films on Si (111)

Silicon nitride layers grown on Si (111) by atomic nitrogen exposure at elevated substrate temperatures have been investigated in situ by photoemission spectro-microsopy. From the X-ray photo emission spectra taken at various sample areas, the chemical composition of samples grown at 800 degreesC is found to be homogenous all over the surface, with a stoichiometry according to Si3N4. Due to attenuation of the photo electrons, the images also provide information about the morphology of the nitride films. For 800 degreesC, a smooth film is observed, whereas for growth temperatures exceeding 900 degreesC, an increased roughness is observed.