Quantitative depth profiling of SiGe-multilayers with the Atom Probe

The laser-assisted Atom Probe has been proposed as ametrology tool for semiconductor technology to meet the requirements accompanying the analysis of the ever smaller and more complex structures targeted for fabrication. In order to support its routine application, we carried out a quantitative assessment of the performance of the Atom Probe (AP) on semiconductor compound multilayers. We analyzed a silicon, silicon-germanium multilayer structure with Atom Probe Tomography (APT), SIMS, Transmission Electron Microscopy (TEM) and high resolution X-ray diffraction (HRXRD), and studied the impact of the laser power on the accuracy. Under optimized conditions, the AP outperforms SIMS by a factor of 3 in terms of depth resolution providing a decay length of less than 0.4-0.6 nm/dec whereas the compositions and layer thicknesses are in close agreement with the SIMS, HRXRD and TEM results. Copyright (C) 2010 John Wiley & Sons, Ltd.