Internal strain distribution in free-standing porous silicon

YU. A. PUSEP; A. D. RODRIGUES; J. C. GALZERANI; R. D. ARCE; R. R. KOROPECKI; D. COMEDI

JOURNAL OF THE ELECTROCHEMICAL SOCIETY

ELECTROCHEMICAL SOC INC

Lugar: New Jersey; Año: 2009 vol. 156 p. 215 - 217

0013-4651

Elastic properties of free-standing porous silicon layers fabricated by electrochemical anodization were studied by Raman scattering. Different anodization currents provided different degrees of porosity in the nanometer scale. Raman lines corresponding to the longitudinal optical phonons of crystalline and amorphous phases were observed. The amorphous volume fraction increased and the phonon frequencies for both phases decreased with increasing porosity. A strain distribution model is proposed whose fit to the experimental results indicates that the increasing nanoscale porosity causes strain relaxation in the amorphous domains and strain build-up in the crystalline ones. The present analysis has significant implications on estimation of the crystalline Si domains characteristic size from Raman scattering data.