From Porous Si to Patterned Si Substrates: Can Misfit Strain Energy in a Continuous Heteroepitaxial Film be Reduced?
13 September 1989
The use of patterned Si substrates (specifically porous Si) for the reduction of heteroepitaxial films strain energy (S. Luryi and E. Suhir, Appl. Phys. Lett. vol. 49(3), 140 (1986) has been studied recently by several research groups. It is the objective of this report to present the experimental result coming out of our studies and to discuss the validity of the original concept. We studied molecular beam epitaxial growth of continuous Ge sub x Si sub (1-x) films on porous Si substrates using Rutherford backscattering spectrometry, transmission electron microscopy, and x-ray rocking curve. The results show predominantly 60degree dislocations with long misfit segments and no reduction in either the strain in the films or the dislocation density is observed comparing to the samples with the same films grown on regular Si substrates.