COMPOSITIONAL EFFECTS ON THE RADIATION-DAMAGE OF 2 MEV SI ION-IMPLANTED RELAXED SI1-XGEX ALLOYS

The radiation damage of relaxed Si1-xGex alloys with 0.04 less than or equal to x less than or equal to 0.36 after 2 MeV Si ion implantation at 300 K has been studied as a function of dose. Optical reflectivity depth profiling (ORDP) is used to determine quantitatively depth prof iles of the lattice damage. While for sufficiently low doses the shape of damage profiles is similar to that of the nuclear stopping power, composition dependent changes in profile shape are observed at doses w here defects produced in different collision cascades may interact. Da mage at any depth is observed to increase with increasing Ge content o f the alloy. The dose dependence of damage is described by a damage ac cumulation model for the depth of damage maximum. From the model param eters it is concluded that the stronger damage in the more Ge-rich all oys is mainly due to a stronger production of amorphous volume portion s in individual collision cascades.