Influence of the structure of the electrodeposited antimony substrate on indium diffusion

The influence of the morphology and structure of antimony substrates on the diffusion and reaction process of an electrodeposited indium overlayer was investigated. The formation of the InSb intermetallic compound was studied by SEM-EDS and X-ray diffraction, at temperatures of 40, 70, 110 and 140 degrees C. The antimony substrates, either crystalline or amorphous, were prepared by electrodeposition, the former being obtained in two different conditions, i.e. from a bath either not containing or containing the surface-active agent, Trylon B. The lowest indium diffusion coefficient was observed for the crystalline substrate prepared in the presence of the organic compound and the highest for the amorphous substrate, in spite of the higher surface roughness of the crystalline material. The values ranged from 0.35x10(-19) to 17.1 x 10(-19) m(2) s(-1), at 70 degrees C. This behaviour was ascribed to the lower activation energy for In diffusion in the amorphous phase (53 instead of 65 kJ mol(-1)) which has a more open structure and lower density than the crystalline structure, due to the larger interatomic distances. (C) 1999 Elsevier Science S.A. All rights reserved.