Surfactant-mediated epitaxy of silicon germanium films on silicon (001) substrates

We report on the surfactant-mediated epitaxy (SME) of Si1 -xGex films with x = 0.23-1 on Si(001) using antimony as surfactant. We observe a transition in strain relaxation at a critical composition xT = 0.58-0.66. Above this value full relaxation is achieved by a network of full edge dislocation confined to the interface in analogy to SME of pure germanium on Si(001). 100 nm thick Si1 −xGex films with surface roughness values less than 1 nm and abrupt interfaces are obtained, as the surfactant reduces strain induced roughening and hinders interdiffusion.