X-ray diffraction analysis of SiGe/Si heterostructures on sapphire substrates

Si/Si1-xGex heterostructures on improved silicon-on-sapphire substrates were grown epitaxially by ultrahigh vacuum chemical vapor deposition for application as p-channel field effect transistors. High-resolution triple-axis x-ray diffraction was used to analyze these structures quantitatively and to evaluate their thermal stability. Outdiffusion of Ge from the strained Si1-xGex quantum well was observed after annealing at 850 °C. The amount of outdiffusion was comparable to that observed in Si1-xGex structures on bulk Si wafers. © 1998 American Institute of Physics.