TEST OF VEGARDS LAW IN THIN EPITAXIAL SIGE LAYERS

Ultrametastable pseudomorphic Si1-xGex layers (on (100) Si) with Ge co ntents x up to 32% and partly relaxed SiGe layers with Ge contents bet ween 35% and 75% were grown by molecular beam epitaxy at growth temper atures between 310 and 575 degrees C. The relation between lattice con stant of the alloy layers and chemical composition (Ge content) was me asured by X-ray methods (reciprocal space mapping) and by Rutherford b ackscattering. Slight negative deviations from the linear relationship (Vegard's law) were found which confirm. very early bulk data gained by Dismukes.