Scanning capacitance microscopy (SCM) has been performed both in cross-sectional and in angle-beveling configurations on ultranarrow B spikes with a full width at the half maximum smaller than the SCM probe diameter. A relevant improvement in the SCM response has been observed passing from the cross section to ten times magnification, but a peculiar asymmetric shape characterizes all the profiles on the beveling configuration and broadening and peak lowering are observed for the narrowest spikes. Accurate two-dimensional simulations allowed us to reproduce the experimentally observed peculiar phenomena. (C) 2004 American Vacuum Society.