Changes in elastic deformation of strained Si by microfabrication

We have investigated microfabrication-associated changes in the elastic deformation of strained Si films by Raman microscopy. The Raman frequency of the Si-Si vibration mode of microstructured strained Si differed from that of the as-deposited film. This result was attributed to the relaxation of the strain by the appearance of the free surface of the structure. Strain parameters were calculated from the observed Raman frequency, with the asymmetric shape of the structure being taken into account. Dependences of the degree and symmetry of the strain, as well as their spatial distributions, on sample dimensions are discussed. Theoretical calculations of energy bands and hole effective mass were carried out to determine the effect of the fabrication-associated relief of elastic strain on the band structures.