STRUCTURAL CHARACTERIZATION OF THE CUIN INTERMETALLIC PHASE PRODUCED BY INTERFACIAL REACTIONS IN CU IN BIMETALLIC FILMS/

The composition, morphology and structure of the new CuIn intermetalli c produced by interfacial reactions in Cu/In bimetallic films have bee n studied by X-ray diffraction and transmission electron microscopy (T EM). Besides development of the CuIn intermetallic, the formation of t he Cu9In4 (delta phase) intermetallic has also been noticed on anneali ng the films at higher temperatures. The CuIn intermetallic has been i ndexed as a monoclinic lattice with cell dimensions a = 0.8234 nm, b = 1.4490 nm, c = 1.0280 nm and beta = 133.79-degrees, and as having a s pace group P12(1)1(4) or P12(1/m)1(ll). The film composition shows Cu and In in a 1:1 ratio. TEM study reveals the mechanism of the developm ent of CuIn grains of average size 250 nm, through grain-boundary inte rstitial diffusion of Cu and In on annealing at 393 K.