Features of Inelastic and Elastic Characteristics of Si and SiO2/Si Structures

Measurement of temperature dependences of internal friction (IF) was performed on identical Si p-type substrates, orientation (100), doped with boron B, with specific resistivity ρ ≈ 7.5 Ohm×cm and thickness h ≈ 4.7·10⁵ nm. The samples passed the same technological route after deposition of a SiO₂ layer with thickness h ≈ 600 nm because of high-temperature oxidation in dry O₂ at T₀ ≈ 1300 K. It was found that the annealing of structural defects in Si changes the shape of the IF temperature spectrum Q ^– 1(T). The IF peaks Q_M ^– 1 formed by point defects could be observed under the condition that Si was heated at a rate V = ΔT/Δt ≤ 0.1 K/s. After X-ray irradiation with a dose γ ≈ 10⁴ R, the IF maximum at T_M1 ≈ 320 K increases sharply; its height Q ^– 1_M1 increases almost threefold with a twofold decrease in the width ΔQ ^– 1_M1, which testifies to the process of relaxation of radiation defects of the same type. The activation energy value H₁ ≈ 0.63 eV was obtained for the IF peak Q_M ^– 1 in the Si plate at T_M1 ≈ 320 K. The proximity of the obtained activation energy H₁ at T_M1 ≈ 320 K to the migration energy H₀ ≈ 0.85 eV for positively charged interstitial atoms Sii+ suggests a relaxation mechanism due to the reorientation of interstitial atoms Sii. Upon electron irradiation, as a result of the collision of electrons with Si atoms, Frenkel defects are formed. Calculations show that the electron energy W ≈ 1 MeV, which corresponds to the experiment, is sufficient to shift Si atoms from their equilibrium positions. After irradiation with a dose γ ≈ 10⁵ R, the IF Q ^– 1_M1 maximum height at T_M1 ≈ 320 K did not change significantly in comparison with the IF Q ^– 1(T) spectrum before irradiation that indicates a special effect of the dose γ ≈ 10⁵ R.