Pyramidal structural defects in erbium silicide thin films

Pyramidal structural defects, 5–8μm wide, have been discovered in thin films of epitaxial ErSi2−x formed by annealing thin Er films on Si(001) substrates at temperatures of 500–800°C. The formation of these defects is not due to oxidation. We propose that they form as a result of the separation of the silicide film from the substrate and its buckling in order to relieve the compressive, biaxial epitaxial stresses. Silicon can then diffuse through the silicide or along the interface to fully or partially fill the void between the buckled erbium disilicide film and the substrate.