Effect of Strain on the Epitaxy of B-Doped Si0.5Ge0.5 Source/Drain Layers

The impact of strain on the growth of in situ boron doped Si0.5Ge0.5 epitaxial layers is discussed. The lattice strain has been varied by changing the Si0.5Ge0.5 thickness and by growing the epitaxial layer on strain relaxed substrates with different Ge concentrations. With decreasing compressive strain, the B incorporation reduces, and the Ge concentration increases. Through density functional theory calculations, the dependence on the applied strain of the energetic cost for boron incorporation into the Si0.5Ge0.5 surface was investigated.