Non-linearity of diffusion in amorphous Si-Ge multilayers

Compositionally modulated amorphous Si-Ge thin films with repeat lengths be tween 2.5 and 9 nm have been prepared using magnetron sputtering. The inter diffusion coefficient (D) was determined from the change in the small angle X-ray diffraction satellite (SAXRD) intensities. Experimental results conf irm the theoretically predicted strong concentration dependence of the inte rdiffusion coefficient. It is illustrated that it is possible to determine the concentration dependence of D from one (curved) decay plot of SAXRB int ensities as well as from Rutherford backscattering measurements. (C) 2001 E lsevier Science Ltd. All rights reserved.