Si acoustic delay lines and the effect of current on accoustic wave attenuation and speed

We studied the effect of excess carriers, temperature and current on acoustic waves in silicon delay lines. Heat and excess carriers reduce the acoustic velocity by respectively reducing the Young´s modulus and through the deformation potential. Electrical current, on the other hand, can increase the acoustic velocity depending on their drift velocity. In addition to current, acoustic waves can also be controlled through field effect and modulation of depletion width in periodic p-n junctions embedded in the delay line.