Thermomigration in indium films

Thermomigration in indium films of thickness 0.5–3 μm was studied between 94 and 145 °C in a scanning electron microscope, using a 10‐μm‐wide Mo heater underneath the In. Transport was from hot to cold. The amount of transported In was determined by measuring the size of the holes appearing in the In above the heater. The activation energy is 0.8 eV. The transport starts after an incubation time and is faster for thinner films, probably because of grain boundary diffusion.