Tip-induced large-area oxide bumps and composition stoichiometry test via atomic force microscopy

Using atomic force microscope (AFM) tip, local large-area oxide bumps were induced on a native SiO2 layer applied with a static 10 V in an ambient surrounding. It can be seen in the backscattered electron (BE) images that the oxide bumps were SiOx layer, not the native SiO2 layer. Also, the spectra of energy dispersive X-ray spectrometer (EDS) displayed that the oxide bumps contained oxygen more than did the native SiO2 layer, indicating that the O/Si ratio of the oxide bump is greater than two. A comparison of the growth rates of the point oxide protrusions on the oxide bumps and on the native SiO2, can be used to directly determined the composition stoichiometry (the O/Si ratio (=x)) of the oxide bumps.