1. Introduction
Defect annealing leads to a change in the shape of the internal friction (IF) temperature spectrum Q-1(T) [1]. IF method allows to set the spectrum of structural defects on the analysis of positions of maximums IF, on duration of relaxation time τ and on their deposit in attenuation of elastic vibrations [2]. A non-destructive method for the technological control of the structure defects by measuring internal friction (IF) and elastic modulus E after laser radiation was developed.
2. Experimental procedure
Ultrasonic (US) pulse-phase method using USMV-LETI, modernized USMV-KNU and computerized “KERN-4” with frequencies f║ ≈ 1 MHz and f┴ ≈ 0,7 MHz, US invariant-polarization method for determining the effective acoustic μil and elastic constants Cijkl were used [3,4]. The measured velocity error was equal to ΔV/V = 0,5÷1,5%.
The study of influence of structure defects on damping of vibrations in Si/SiO2 wafer-plates by the diameter of D = 100÷60 mm and by the thickness of hSiO2 ≈ 600 nm, hSi ≈ 470 000 nm, allows to estimate the degree of perfection of crystalline structure
Metallography optical supervision of microstructure by means of the microscope ”LOMO MVT”, atomic-force microscopy (AFM) were used.
3. Results and discussion
The quasi-longitudinal US velocity V║[001] = 5870 m/s, elastic modulus E001 = ρV║[001]2 = 80,28 GPa for SiO2/Si from the oscillogram were determined. Temperature dependence of internal friction Q-1(T) in SiO2/Si wafer-plate p-type, doped with B, KDB-7.5(100) diameter D ≈ 76∙10-3 m, thickness hSi ≈ 460∙103 nm with SiO2 layer thickness hSiO2 ≈ 100 nm after X-ray irradiation with dose Dγ ≈ 102 Gy is showed.
4. Conclusions
1. The growth of internal friction maximum height QM-1 testifies the growth of the structural defects concentration n, and the broadening of internal friction maximum ΔQM-1 here represents the relaxation process of structural defects new types in SiO2/Si wafer-plate.
2. It was found that as the result of the structural defect annealing IF background Q0-1 significantly decreases during measuring of IF temperature dependence Q-1(T), which indicates the improvement of SiO2/Si crystal structure.
3. The elastic modulus Е, the shear modulus G, Poisson coefficient μ, IF Q-1 are dependent from SiO2/Si wafer-plate anisotropy.
4. The value of IF background Q-10 after temperature T, mechanical treatments describes the changes of the elastic stress σi fields in SiO2/Si wafer-plate.
5. The study of vibrations of disk wafer-plate Si/SiO2 at different harmonic frequencies f0, f2 made it possible to develop the technique for determining the structural defects density nD for semiconductor wafers-substrates.
6. The relationship between IF Q-1 value, the logarithmic decrement of ultrasound damping δ and the dislocations density nD was established for disk-shaped semiconductor wafers-substrates.
Acknowledgements
This work has been supported by Ministry of Education and Science of Ukraine: Grant of the Ministry of Education and Science of Ukraine for perspective development of a scientific direction "Mathematical sciences and natural sciences" at Taras Shevchenko National University of Kyiv.
References
[1] Golovin I. S. 2012 Internal friction and mechanical spectroscopy of metal materials (Moscow: Publishing company MISIS).
[2] Shpak A. P., Kunickiy Y. A. and Karbovskiy V. L. 2001 Cluster and nano structural materials (Kyiv: Academy periodicals).
[3] Onanko A. P., Kuryliuk V. V., Onanko Y. A. et al. 2020 Peculiarity of elastic and inelastic properties of radiation cross-linked hydrogels. J. Nano- Electron. Phys. 12, № 4, 04026(5).
DOI: https://doi.org/10.21272/jnep.12(4).04026.
[4] Onanko A. P., Kuryliuk V. V., Onanko Y. A. et al. 2021 Features of inelastic and elastic characteristics of Si and SiO2/Si structures. J. Nano- Electron. Phys. 13, № 5, 05017(5).
DOI: https://doi.org/10.21272/jnep.13(5).05017.
