Observation of stacking faults in strained Si layers

Defects in strained Si layers grown on relaxed SiGe layers were studied using chemical etching and transmission electron microscopy. Defect densities were measured in strained Si layers formed on SiGe buffer layers grown on bulk Si, as well as silicon–germanium-on-insulator substrates. It is found that, in addition to threading dislocations and dislocation pile ups, stacking faults are present in nearly all of the materials studied. The stacking faults are shown to originate in the relaxed SiGe alloy suggesting that they form during the relaxation of the SiGe layer.