High depth resolution analysis of Si/SiGe multilayers with the atom probe

The laser assisted atom probe has been proposed as a metrology tool for next generation semiconductor technologies requiring subnanometer depth resolution. In order to support its routine application, we carried out a quantitative assessment of the performance of the atom probe on semiconductor stacks. We analyzed a silicon, silicon-germanium multilayer-structure with atom-probe tomography (APT), secondary ion mass spectroscopy (SIMS), transmission electron microscopy (TEM), and high-resolution x-ray diffraction (HRXRD). We demonstrate that APT outperforms SIMS by a factor of 3 in terms of depth-resolution providing a decay length of 0.2–0.6 nm/decade whereas the compositions and layer thicknesses are in close agreement with SIMS, HRXRD, and TEM.