Structural and Mechanical Properties of Sintered Porous Silicon

Inhalt:
Significant structural changes occur when porous silicon is thermally annealed in hydrogen environment. We investigate the mechanical properties of sintered porous silicon in terms of biaxial elastic modulus for (001) wafer surface orientations. Our analytical calculations using the effective media theory show that the biaxial modulus gradually decreases as the fraction of void space in the material increases and also that the shape of the voids have a considerable effect on the results. X-ray diffraction measurements and bi-layer bending experiments indicate that the unstrained lattice constant of sintered porous silicon is smaller than that of bulk silicon and hence a sintered porous silicon layer on a bulk substrate is tensily stressed. Finally, finite element simulation analysis is used to verify the previously determined values of elastic constants and misfit strain of sintered porous silicon.