ELASTIC PROPERTIES OF SEMICONDUCTOR a-ShH/a-SiN_x:H QUASIPERIODIC AND PERIODIC SUPERLATTICES

摘要

Surface Rayleigh acoustic waves and related elastic properties of quasiperiodic and periodic modulated a-SiiH/a-SiN_x:H superlattices have been studied by means of a light-scattering technique. Changes in the phase velocity of the surface Rayleigh acoustic waves as a function of sublayer (a-Si:H) thickness are interpreted using an effective medium model. Despite the existence of structural mismatch in the bond-length and coordination number and of structural disorder in the bond-angle for Si-N and Si-Si, no appreciable discrepancy between the measured results and the theoretical predictions has been found.