Three‐Dimensional Atomic‐Scale Tomography of Buried Semiconductor Heterointerfaces

Abstract

yields two-dimensional projections and hence does not resolve the third dimension of the interface.Atom probe tomography (APT) with its capability of imaging the local chemistry in three-dimensions at the near atomic scale is a prime candidate for achieving atomic-scale characterization of buried interfaces. [12][13][14][15] However, limitations arising from the comparatively simple algorithms to reconstruct APT data are known to cause significant aberrations near interfaces, limiting accuracy. [12,[16][17][18] One way to address this issue is to improve APT data reconstruction using simulations or calibrations from electron tomography. [19,20] Both approaches are however time consuming and rely on information not readily available from an APT analysis.Here, we propose an alternative approach. Instead of trying to correctly reconstruct the entire volume analyzed in the tomography, we develop a protocol that allows us to choose a set of reconstruction parameters for one interface at a time by combining brute force search with a simple, standard reconstruction algorithm [16] from data exclusively acquired during APT. We present a fully automated process that is highly reproducible and enables us to characterize interface widths and roughness on a sub-nanometer scale.

Modeling Si/SiGe quantum dot variability induced by interface disorder reconstructed from multiperspective microscopy

“…1b, c, and diffuse alloy disorder essentially ruling out abrupt stepped interfaces. Reported interface widths span 0.7-1.0 ± 0.3 nm, i.e., several atomic layers, with alloy number fluctuations adding variability 28,49,50 . Hence, recent theory, simulation, and experiment focus primarily on VS variability owing to random alloy disorder and alloy fluctuations 23,25,28,51 .…”