Dislocation engineering without oxide masks was demonstrated. By using finite-element simulations, it was showd how nanopatterning of Si substrates with {111} trenches provided anisotropic elastic relaxation in a SiGe film, generated preferential nucleation sites for dislocation loops, and allowed for dislocation trapping; leaving wide areas free of threading dislocations. These predictions were confirmed by atomic force and transmission electron microscopy performed on . overcritical Si0.7Ge0.3 films. These were grown by molecular beam epitaxy on a Si(001) substrate patterned with periodic arrays of selectively etched {111}-terminated trenches.

Dislocation Engineering in SiGe Heteroepitaxial Films on Patterned Si (001) Substrates. R.Gatti, F.Boioli, M.Grydlik, M.Brehm, H.Groiss, M.Glaser, F.Montalenti, T.Fromherz, F.Schäffler, L.Miglio: Applied Physics Letters, 2011, 98[12], 121908