TEMPERATURE-DEPENDENT SEGREGATION OF METALS AT SI-SIO2 INTERFACES DURING OXYGEN-ION BOMBARDMENT

Rutherford backscattering and channeling techniques have been used to study temperature-dependent segregation of Cu, Au, and Pd at Si-SiO2 i nterfaces during high dose 15 keV O+ bombardment of Si. Results illust rate a strong tendency for metals to be retained in an amorphous Si la yer adjacent to the continuous SiO2 layer formed by O+ bombardment of Si. The magnitude of segregation depends on the bombardment temperatur e. We explain our temperature-dependent data in terms of a thermodynam ic model whereby the segregation is driven by a large solubility diffe rence between metals in amorphous Si and SiO2. Segregation is enhanced when the metal diffusivity in amorphous Si is high. (C) 1997 American Institute of Physics.