Subsurface measurement of nanostructures on GaAs by electrostatic force microscopy

The size of surface buried oxide nanostructures are measured by electrostatic force microscopy (EFM). In contrast to atomic force microscopy that cannot probe subsurface structures and thickness, we show that EFM data include information about the thickness of individual nanostructures, consequently allowing us to determine the thickness of buried nanostructures on semiconductor substrates. We further show that this measurement can be performed simultaneously with AFM using EFM modulation spectroscopy.

► We showed how the thickness of buried nanostructures beneath the semiconductor substrate can be measured by modified electrostatic force microscopy. ► The electrostatic force between the tip and the substrate depends on the height of individual nanoparticles. ► The electrostatic force depends strongly on the distance between the tip and the surface. ► We can estimate the thickness of the surface nanostructures from the fit curve for the experimental results.