Feasible atomic-resolution electron tomography for general crystal surfaces by quantitative reconstruction from a high-resolution image

Whether or not the 3-dimensional surface morphologies of a crystal sample can be reconstructed at atomic-scale from a single 2-dimensional image becomes an interesting issue in high-resolution transmission electron microscopy, after the work by Jia et al. [1]. Here we propose an improved and self-validated algorithm to enhance such an electron tomography method and to make it applicable to more general crystal surfaces even with thin amorphous layers. Our study shows that a resolution in the beam (z) direction and a confidence level have to be defined and estimated after performing tomographic reconstruction in order to evaluate the quality and the reliability of its result. Applying the proposed procedure to the Si[110] image to recover the surface morphologies of a silicon crystal with amorphous contamination, the obtained results show that an atomic-resolution of 0.384 nm in the z-direction and a high confidence level of 95% are achieved for imaging the Si-surface structures, quantitatively described by tomographic parameters, i.e., the height (defocus) and the thickness (atom number) of Si-atomic columns.