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 d egrees C. The antimony substrates, either crystalline or amorphous, were pr epared by electrodeposition, the former being obtained in two different con ditions, i.e. from a bath either not containing or containing the surface-a ctive agent, Trylon B. The lowest indium diffusion coefficient was observed for the crystalline substrate prepared in the presence of the organic comp ound and the highest for the amorphous substrate, in spite of the higher su rface 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 asc ribed to the lower activation energy for In diffusion in the amorphous phas e (53 instead of 65 kJ mol(-1)) which has a more open structure and lower d ensity than the crystalline structure, due to the larger interatomic distan ces. (C) 1999 Elsevier Science S.A. All rights reserved.