Imaging of Si nano-patterns embedded in SiO2 using scanning electron microscopy

Detailed shapes of embedded Si nanostructures were clearly observed through a SiO2 layer using scanning electron microscopy (SEM). We Pound a new imaging mechanism by which secondary electron (SE) yield from the oxide surface is greater where an embedded Si structure exists. In the range of acceleration voltages from 5 to 200 kV, we found that 30 kV provides high contrast and high resolution. Controlling the surface contrast by depositing a contaminated film using electron beam irradiation yields a clear, high-resolution SEM image of sub-10-nm Si structures embedded in a 60-nm-thick oxide. The combination of a non-destructive observation method based on SEM with a method based on AFM, which was demonstrated previously, provides detailed information on the three-dimensional shape of embedded Si nanodevices.