Study of solid surfaces by metastable electron emission microscopy: Energy-filtered images and local electron spectra at the outermost surface layer of silicon oxide on Si(100)

Abstract

We have observed images and local electron spectra of an oxide pattern on Si(100) using metastable electron emission microscopy (MEEM) recently developed at our laboratory. Low-energy electron microscopy (LEEM) was also used. For both MEEM and LEEM, the energy-filtered images were obtained for the first time. It was shown that MEEM gives the information on the outermost surface layer selectively, while LEEM provides averaged information on several surface layers. The intensity of the band in the local electron spectrum of MEEM can be related to the distribution of the relevant orbitals exposed outside the surface, with which metastable atoms interact effectively. Thus, using energy-filtered MEEM, we can observe the map reflecting the distribution of individual orbitals at the outermost surface layer.