Study on Stem EDS for GESI Atomic Layer Interface Identified and Concentration Quantified

The Transmission Electron Microscope (TEM) with its high spatial resolution, combines morphology observation, crystal structure identification, and chemical composition analysis functions, enabling direct observations of morphology, interfaces, and crystal defects from the micron to atomic scale. This technology is essential for analyzing the nano-scale GeSi Film and its 2-3 Dumbbell atoms interface distribution in Finfet advanced process to achieve corresponding process optimization. However, traditional Secondary Ion Mass Spectrometry (SIMS) is limited to analyzing the GeSi concentration of bare wafer due to its micrometer scanning spot. Atom Probe Tomography (APT) offers great advantages for quantitative analysis of GeSi concentration in devices, but it has a low success rate and high cost due to the necessary Focused Ion Beam (FIB) sample preparation and on-board APT analysis. X-ray Energy Dispersive Spectroscopy (EDS) is generally limited to qualitative and semi-quantitative analysis, making accurate quantitative analysis of GeSi concentration in devices leads to a key challenge in EPI process development. In this study, we focused on developing High-Angle Annular Dark Field (HAADF) imaging technology based on spherical aberration-corrected scanning transmission electron microscopy (STEM), as well as utilizing EDS and Electron Energy Loss Spectroscopy (EELS) component characterization techniques for ultra-high resolution interface analysis of GeSi films. By optimizing FIB sample preparation methods, combined with EELS Zero Loss monitoring of sample thickness and SIMS calibration of GeSi bare wafer concentrations, EDS can achieve comparable accuracy with SIMS in quantitatively analyzing the GeSi concentration in devices with deviation values less than 1% and maintaining stability across multiple tested data. Currently, a single EDS analysis method can be used for quantitative analysis of GeSi in devices.