Thermal Stability of Strained Si on Relaxed SiGe Buffer Layers

The thermal stability of strained Si on relaxed Si1-xGex structures annealed at 1000 oC
was investigated using high-resolution x-ray diffraction, Raman spectroscopy and transmission
electron microscopy. Interdiffusion at the Si/Si1-xGex interface is negligible for annealing times
<30 sec and is independent of the initial Si layer thickness and the composition of the Si1-xGex
layer. In all cases the Si layers remained nearly fully strained, but a significant density of misfit
dislocations was seen in layers that exceeded the critical thickness for dislocation glide. The Si
layer thickness could be measured for layers as thin as 7 nm.