Identification of the Structure of Nanoscale Layers of Multilayer Heterocomposites using Transmission Electron Microscopy

The methods of transmission electron microscopy and high-resolution electron microscopy, used to study multilayer heterocomposites, have limitations in resolution, do not allow for the effective investigation of amorphous materials and require the analysis of many local areas in the case of samples consisting of individual crystallites. In this work, we investigate a multilayer heterocomposite, which is a phase-shift photomask consisting of layers of nanoscale thickness on the surface of a glass substrate. Focused-ion-beam methods are used to study a thin foil of cross and longitudinal sections. To identify the structure and determine the composition of the layers, the methods of transmission electron microscopy and energy-dispersive X-ray microanalysis are used. The analysis of cross-sectional foils prepared using standard approaches allows visualization, thickness measurements, and determination of the layer compositions. It is shown that on the SiO 2 substrate an amorphous layer of Mo 0.06 Si 0.31 N 0.63 93 nm thick is formed, which is successively coated with polycrystalline layers of Cr 0.56 N 0.44 , Cr 0.74 C 0.06 N 0.2 , and Cr 0.4 N 0.26 O 0.3 with thicknesses of 22, 37, and 8 nm, respectively. A thin foil with a planar cross-section, prepared at a slight inclination to the surface of the photomask, makes it possible to form sections of all layers with dimensions sufficient for their study by electron microdiffraction. The performed electrographic analysis confirmed the amorphous structure of the substrate and Mo 0.06 Si 0.31 N 0.63 layer, and also showed that polycrystalline layers of Cr 0.56 N 0.44 , Cr 0.74 C 0.06 N 0.2 , and Cr 0.4 N 0.26 O 0.3 formed by crystallites with a cubic lattice and parameters of 3.92, 4.18, and 4.12 Å, respectively.