IN SITU STRESS MAPPING DURING SILICON INDENTATION USING RAMAN SPECTROSCOPY

Due to the features of the transparent diamond indenter-objective, it became possible to study in situ the areas of elastic deformations of materials under the tip both in contact and outside the contact area, without the use of special immersion liquids. In this regard, it has become possible to effectively point-scan these regions down to 1 µm using Raman spectroscopy. In this work, relative volume changes and their corresponding pressures, which are the average of all three normal stress components, were pointwise calculated from Raman mode shifts (LO modes) due to the concept of the Grüneisen phonon mode tensor in deformed silicon. The transition from mapping of optical properties to determination of mechanical properties of the investigated material with spatial referencing of the obtained data with micron precision was demonstrated. The possibility of studying the type of deformation in crystals (tension or compression) during indentation using Raman spectroscopy in backscattering geometry is discussed. The possibility of determining the strain direction using polarization techniques is also being discussed the use of which will allow the longitudinal TO modes to be measured. In this work, a silicon chip sample with orientation (100) was investigated. Indentation was carried out at loads of 250 and 1500 mN. Using the data obtained for a load of 250 mN for one of the sectors under the indenter, a pressure distribution map with a step of 1 µm of the elastic deformation region outside the indentation was plotted. Conclusions were made about the homogeneity and inhomogeneity of deformations at the measured points based on the character of changes in Raman spectra. Stress mapping of the deformed region using the proposed technique is effective at low loads. For citation: Votyakov S.A., Kudryashov I.A., Budich C., Kirichenko A.N., Useinov A.S., Sultanova G.Kh. In situ stress mapping during silicon indentation using Raman spectroscopy. ChemChemTech [Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol.]. 2024. V. 67. N 10. P. 22-28. DOI: 10.6060/ivkkt.20246710.10y.