Characterization of Nanoscale Layers of Heterocomposites Using the Digital Processing of Transmission Electron Microscopy Data

Modern transmission electron microscopy makes it possible to carry out comprehensive studies of the structure and determine the composition of layers in various heterocomposites. The use of transmission electron microscopy to characterize layers of nanoscale thickness requires the development of quantitative methods for analyzing electron microscopy data. In this work, the layers of a phase-shift photomask, which is used in lithography operations in microelectronics, are studied using electron microscopy data analysis methods. It is determined that in the cross-sectional samples, layers of Mo0.03Si0.36N0.61, Cr0.49C0.03N0.48, and Cr0.38C0.05N0.28O0.29 are located on the surface of the SiO2 substrate. It is found that quantitative analysis of one-dimensional intensity profiles calculated by averaging its distribution in electron microscopy images along the substrate provides a precise measurement of the thickness of the heterocomposite layers, which amounts to (69.91 ± 0.12) nm for the molybdenum-containing layer, (26.42 ± 0.17) nm and (20.00 ± 0.20) nm for the chromium-containing layers. The analysis of high-resolution electron micrographs and electron diffraction patterns obtained from planar-section samples shows that the molybdenum-containing Mo0.03Si0.36N0.61 layer is amorphous, and the chromium-containing layers Cr0.49C0.03N0.48 and Cr0.38C0.05N0.28O0.29 have a polycrystalline structure and are formed by crystallites with a cubic lattice with parameters of 0.406 and 0.408 nm, respectively. As a result of digital image processing, it is revealed that in the Cr0.49C0.03N0.48 and Cr0.38C0.05N0.28O0.29 layers the average lateral sizes of crystallites are close to 6.7 and 7.4 nm, the average pore sizes are approximately 1.7 and 2.5 nm, and their porosity is 6.4 and 16.6%, respectively. The obtained results demonstrate the effectiveness of the proposed methods for quantitatively assessing the thickness and porosity of photomask layers and can be used in the electron microscopy studies of various heterocomposites with nanoscale layers.