Hetero-epitaxy of Ge sub x Si sub (1-x) on Porous Si Substrates.

Molecular beam epitaxial growth of Ge sub x Si sub (1-x) on 100> porous Si substrate was studied using Rutherford backscattering spectrometry, transmission electron microscopy, and defect etching. This study was stimulated by the theoretically predicted possibility of stress field reduction in a lattice mismatched film growth on a patterned substrate. The experimental results show predominantly 60degrees dislocations with long misfit segments, and no reduction of dislocation density is observed by the use of porous Si substrates. The nature of the interconnected growth area of the porous Si substrate is believed to be the reason for the ineffectiveness of the stress reduction.