MECHANISMS OF ION-BEAM MIXING IN METALS AND SEMICONDUCTORS

Ion beam mixing was investigated in crystalline and amorphous semicond uctors and metals using molecular dynamics simulations. The magnitude of mixing in an amorphous element compared to its crystalline counterp art was found to be larger by a factor of 2 or more. Mixing in semicon ductors was found to be significantly larger than in a face-centered-c ubic (fcc) metal of corresponding mass and atomic density. The differe nce in mixing between amorphous and crystalline materials is attribute d to local relaxation mechanisms occurring during the cooling down pha se of the cascade. Comparison of mixing in semiconductors and metals s hows that short range structural order also has a significant influenc e on mixing. The mixing results in fee metals indicate that the role o f the electron-phonon coupling in the evolution of collision cascades may be less significant than previously thought. (C) 1998 American Ins titute of Physics. [S0021-8979(98)02903-X].