Depth sensitivity of subsurface imaging using atomic force acoustic microscopy: FEA Study

Atomic force acoustic microscopy makes it possible to image objects below the surface of a sample. Such subsurface imaging capabilities are of great interest in electronics, semiconductors, (bio)materials and manufacturing, polymers and microbiology. In this article, we report a numerical method to study the subsurface depth sensitivity. We calculated the depth sensitivity of atomic force microscopy and atomic force acoustic microscopy for subsurface objects of different heights and elasticity, as well as for different probe radii, applied forces and indentation depths. We also conducted experiments to validate the simulations. The results indicate that atomic force acoustic microscopy has higher subsurface depth sensitivity than atomic force microscopy.