Random walk of liquid droplets migrating in silicon

The dislocation-induced randum walk of an aluminum-rich droplet migrating in a thermal gradient along the 〈100〉 axis in silicon is shown to lead to an appreciable mean square displacement of the droplet from is original 〈100〉 thermal trajectory over migration distances of about 1 cm. When ordered arrays of droplets are migrated to produce columnar diode arrays in silicon, this random walk causes disregistry in the arrays. The disregistry can be minimized by introducing a small off-〈100〉-axis thermal gradient superimposed on the major 〈100〉 thermal gradient. This off-axis component of the thermal gradient overwhelms dislocation intersection effects which cause random walk and leads to a uniform nonrandom displacement which preserves the registry in the columnar diode arrays.