Observation of open-ended stacking fault tetrahedra in Si_0.85Ge_0.15 grown on V-grooved (001) Si and planar (111) Si substrates

A new strain relief mechanism was observed in lattice mismatched epitaxial layers grown on (111) surfaces. Thin films of Si_0.85Ge_0.15 were epitaxilly grown by rapid thermal chemical vapor deposition on patterned (001) and planar (111) Si substrates. The (001) Si substrates were lithographically patterned and anisotropically etched to produce a line pattern of V-shaped grooves running in the [110] direction where the walls of the grooves were the {111} crystal planes. Cross-section and plan-view transmission electron microscopy studies revealed the presence of open-ended stacking fault tetrahedra in Si_0.85Ge_0.15 grown both on (111) Si wafers and the {111} side walls of the patterned (001) Si wafers. No defects were observed in the (001) portions of the films grown on nonplanar substrates.