Theoretical and experimental revision of surface acoustic waves on the (100) plane of silicon

Abstract

The phase velocity dispersion of the surface acoustic waves on a basal plane of Si(100) has been calculated in the whole range of the azimuthal angle of propagation. We present a detailed description of the calculations. These calculations are compared with the experimental data obtained by a laser acoustic method. Our data convincingly demonstrate the existence of a gap in the spectrum of the phase velocities. The gap means that in a definite range of the phase velocities the SAWs are absent in the whole interval of the azimuthal angles. There is an excellent coincidence between the numerical and experimental data.

Scanning Electron Microscopy Investigation of Surface Acoustic Wave Propagation in a 41° YX-Cut of a LiNbO3 Crystal/Si Layered Structure

“…The third resonance at f = 195.7 MHz corresponds to the SAW excitation in the LiNbO3/Si layered structure. In this case, the velocity of the SAW propagation is VSAW = 195.7 × 30 = 5871 m/s, which exceeds the value of the SAW and PSAW velocities in the Si(100) along the [110] direction (VSAW = 5080 m/s, VPSAW = 5570 m/s) [35][36][37][38].…”

“…The third resonance at f = 195.7 MHz corresponds to the SAW excitation in the LiNbO 3 /Si layered structure. In this case, the velocity of the SAW propagation is V SAW = 195.7 × 30 = 5871 m/s, which exceeds the value of the SAW and PSAW velocities in the Si(100) along the [110] direction (V SAW = 5080 m/s, V PSAW = 5570 m/s)[35][36][37][38].Only two resonances can be observed for the 41 • YX-cut of a LiNbO 3 crystal on Figure3. The first resonance at f = 123.1 MHz corresponds to the SAW with a velocity of V SAW = 3639 m/s, which correlates with the known velocity value for the 41 • YX-cut of a LiNbO 3 crystal[33].…”

“…The presence of a thin crystal LiNbO 3 layer allows the excitation of the SAW with higher velocity in the LiNbO 3 /Si layered structure, which should propagate along the [110] direction. The SAW velocity in the Si(100) along direction [110] did not exceed 5080 m/s [34,35]. A number of papers [6,36] have demonstrated that the SAW and PSAW velocities in layered structures can exceed the velocities of their respective bulk crystals.…”

Structural health monitoring through surface acoustic wave inspection deployed on capillaries embedded in additively manufactured components

“…Most of the surface acoustic energy is contained in the Rayleigh pulse, which propagates at a constant velocity 𝑣 𝑅 , independent of the frequency. Their amplitude typically decays exponentially into material with most energy concentrated in a one-wavelength thick waveguide just below the free surface [1,2].…”

“…These surface imperfections cause both dispersion, i.e. dependency of the phase velocity to the wave frequency and attenuation, providing a fingerprint of the inspected surface [2].…”