Photoyield spectromicroscopy of silicon surfaces using monochromatic synchrotron radiation

A photoemission electron microscope has been used to generate spatial maps of silicon surfaces, along with chemical spectroscopy of the silicon core levels at micron-scale spatial resolution. The electron optics permits scanned photon energy imaging of the sample surface, with image capture at video rates in a 512×512 pixel buffer memory. The image is generated primarily by low-energy secondary electrons produced by photoabsorption. Near-edge structure in the image photoyield as a function of photon energy is used to determine the oxidation state of microscopic regions of the surface of a single-crystal Si(111) sample. These measurements show that spectroscopic imaging with 100-nm resolution will be possible using undulator generated synchrotron radiation.