NOVEL METHOD OF STRAIN-RELAXED SI1-XGEX GROWTH ON SI(100) BY MBE

In order to realize high quality strain-relaxed Si1-xGex layers withou t island growth, the Si1-xGex layers with Ge fractions of 0.3 to 1 hav e been grown on Si(100) substrates by a two-step growth method. The fi rst Si1-xGex layer was grown on Si substrates with a thickness of 50 n m at room temperature. After the growth, the substrate was annealed at 710 degrees C for 20 min and then the 200 nm thick second layer was g rown at 710 degrees C. By this method, the strain-relaxation is well a chieved in the Ge fraction range from x = 0.3 to 1. This method has be en found to have also the advantages that the atomic mixing at the Si1 -xGex/Si interface is prevented and the crystalline quality of Si1-xGe x layers is improved.