X-RAY-DIFFRACTION ANALYSIS OF SIGE SI HETEROSTRUCTURES ON SAPPHIRE SUBSTRATES/

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