Surface analyses of Zr (film)/4H-SiC (substrate) by synchrotron radiation induced-PEEM

Abstract

Photoemission electron microscopy (PEEM) has been applied to systems such as Fe, Cu, Ti and Zr on SiC substrates. The products on the surface that result from SiC decomposition and reaction with the deposited metal films can be well imaged by PEEM using synchrotron radiation, 40–130eV and a high-pressure Hg arc-discharge lamp as light sources. Although some PEEM systems have an energy filter, we have explored the capability of PEEM without such a filter in determining the surface structure and composition. We do this by observing the image contrast as we varied the sample temperature and by tuning the photon energy of the synchrotron radiation, which causes a variation of the photoelectron yield corresponding to different surface products. A 5nm Zr film was evaporated in ultra-high-vacuum (UHV) on a 4H-SiC substrate. The sample temperature was raised from room temperature (RT) to 1000°C at the rate of 20°C/min. The PEEM images observed and recorded in real time gave information that no reaction occurred between Zr and SiC, which was not the case for several metals, e.g., Fe, Cu, Ti, etc. Soft X-ray fluorescence spectroscopy (SXFS) study supported the above conclusion.