Novel method to introduce uniaxial tensile strain in Ge by microfabrication of Ge/Si1−xGex structures on Si(0 0 1) substrates

We have proposed a novel method to form by microfabrication a uniaxial tensile strained Ge layer due to the elastic strain relaxation of a Si1−xGex buffer layer on a Si(0 0 1) substrate. A fully strain-relaxed Ge layer on a compressive strained Si0.60Ge0.40 was epitaxially grown on Si(0 0 1) substrate and striped mesa lines were fabricated with a line width of 250 nm along the [1 1 0] direction. The strain of the Si0.60Ge0.40 layer was found to be elastically relaxed only along the direction perpendicular to the lines and a uniaxial tensile strained Ge layer was thus formed. The value of tensile strain of the Ge layer is estimated to be 0.25%.