Non-linearity of diffusion in amorphous Si–Ge multilayers

Abstract

Compositionally modulated amorphous Si–Ge thin films with repeat lengths between 2.5 and 9 nm have been prepared using magnetron sputtering. The interdiffusion coefficient ( D) was determined from the change in the small angle X-ray diffraction satellite (SAXRD) intensities. Experimental results confirm the theoretically predicted strong concentration dependence of the interdiffusion coefficient. It is illustrated that it is possible to determine the concentration dependence of D from one (curved) decay plot of SAXRD intensities as well as from Rutherford backscattering measurements.