Composition dependent structural modification in relaxed Si1−xGex films by 100 MeV Au beam

We report the modification of molecular beam epitaxy grown strain-relaxed single crystalline Si1−xGex layers for x=0.5 and 0.7 as a result of irradiation with 100 MeV Au ions at 80 K. The samples were structurally characterized by Rutherford backscattering spectrometry/channeling, transmission electron microscopy (TEM) and high-resolution X-ray diffraction before and after irradiation with fluences of 5×1010, 1×1011 and 1×1012 ions/cm2, respectively. No track formation was detected in both the samples from TEM studies and finally, the crystalline to amorphous phase transformation at 1×1012 ions/cm2 was examined to be higher for Si0.3Ge0.7 layers compared to Si0.5Ge0.5 layers.