Scanning capacitance microscopy study of carrier depletion within grains of n-type polycrystalline silicon

The local electrical properties and corresponding surface topography for phosphorus-doped n-type polycrystalline (n-poly) silicon layers were investigated using scanning capacitance microscopy (SCM) of chemical mechanical polishing (CMP) and backside-etched samples. Applying negative bias stress between a sample and a scanning SCM probe tip was found to induce a depleted region within the CMP n- poly-Si sample. In contrast, bias stressing does not intrinsically change the backside-etched n-poly-Si sample. By combining our results with the results of energy dispersive x-ray spectroscopy measurement, we can conclude that the active dopant concentration within n-poly-Si grains is inhomogeneous. Copyright © 2008 John Wiley & Sons, Ltd.