(Invited) Epitaxial Growth of Low Defect SiGe Buffer Layers for Integration of New Materials on 300 mm Silicon Wafers

We report on the structural characterization of state-of-the-art SiGe graded buffers on Si(001) substrates with a diameter of 300 mm with and without a backside stressor. The main beneficial effect of the backside stressor is a clear improvement in surface morphology in terms of reduced surface roughness and substantially decreased density of threading dislocation pile-ups all across the wafer. X-ray diffraction furthermore proves that the relaxation of the various layers in the SiGe buffer is triggered by the misfit stress of the subsequently deposited layer. In addition, spatially resolved micro-Raman studies demonstrate that the formed cross hatch pattern surface morphology is clearly correlated with strain field and not with Ge concentration fluctuations.