X-ray absorption micro spectroscopy using Kelvin force microscopy with an X-ray source

To investigate the electronic states of surface electron-trapping centers, Kelvin force microscopy with an X-ray source (X-KFM) was developed. An X-KFM signal with respect to the X-ray photon energy represents the X-ray absorption spectrum in a specific sample-bias condition, minimizing secondary electrons from bulk. The X-KFM signal is generated by photoionization of the surface trapping center under the probe, and this bias condition emphasizes the local information. The absorption spectrum of a trapping center on a Si wafer with native oxide was explained from a structural model proposed in a previous study: the trapping center is Si with insufficient 0 termination at the atomic step edge. The X-KFM image emphasized the electronic states intrinsic to the trapping center, enabling the chemical states on the sample surface to be mapped. (c) 2005 Elsevier B.V. All rights reserved.