Significant reduction of crack propagation in the strained SiGe/Ge(111) induced by the local growth on the depth-controlled area patterning

We propose a method for obtaining crack-free fully-strained SiGe layers on Ge(111). To achieve the crack-free strained SiGe layers, we introduce a patterned area with a sufficient depth (step height) of more than 1 mu m on Ge(111) substrates. Because of the complete suppression of the crack propagation from the SiGe layer grown on the outside of the patterned area on Ge(111), we achieve crack-free fully strained SiGe layers on the inside of the patterned area. This approach will drastically expand the applicability of the strained SiGe to the fields of Si photonics and spintronics.