LEEM and XPEEM studies of C-AFM induced surface modifications of thermally grown SiO2

The process of local anodic oxidation, where a positive voltage is applied between a sample and a conducting probe, is well understood. Here, conducting atomic force microscope (C-AFM) induced surface modifications of thermally grown SiO2 are investigated for opposite (i.e. negative) sample bias. Also at this polarity, surprisingly, the appearance of protrusions is observed. To obtain information on the nature of these protrusions, low-energy electron microscopy (LEEM) and X-ray photoemission electron microscopy (XPEEM) measurements were performed. Photoemission spectra reveal that the structures formed by C-AFM are chemically homogeneous, and that they are caused by the growth of additional SiO2 on the sample surface.