Diffusion and Segregation in Grain and Interphase Boundaries
Grain Boundary Diffusion and Segregation in Cu and Cu-Based Alloys
Grain boundaries present a short circuit path for diffusion which dominate the atomic transport in
nano-crystalline materials. Especially in the Cu metallization of modern microelectronic devices grain
boundaries are critical, as they accelerate the electromigration and thus limit the lifetime of the device. In order to
explore the diffusion and segregation properties of various impurities in Cu-based alloys, controlled radio-tracer
experiments were done in the type B and type C kinetic regimes. By a quantitative comparison of
these two regimes, the segregation factor and the segregation enthalpy of Fe and Ni could be determined in the
limit of a dilute system. Up to now, there is no alternative experimental method to determine segregation factors
with the required sensitivity. In the case of Fe extraordinarily high segregation factors in the range
105 to 106 were experimentally demonstrated for the first time.
