ELASTIC PROPERTIES OF SEMICONDUCTOR A-SI-H A-SINX-H QUASI-PERIODIC AND PERIODIC SUPERLATTICES/

Surface Rayleigh acoustic waves and related elastic properties of quas iperiodic and periodic modulated a-Si:H/a-SiNx:H superlattices have be en studied by means of a light-scattering technique. Changes in the ph ase velocity of the surface Rayleigh acoustic waves as a function of s ublayer (a-Si:H) thickness are interpreted using an effective medium m odel. Despite the existence of structural mismatch in the bond-length and coordination number and of structural disorder in the bond-angle f or Si-N and Si-Si, no appreciable discrepancy between the measured res ults and the theoretical predictions has been found.