Alloying and electrical properties of evaporated Cu-In bilayer thin films

Structural and electrical properties of the Cu-In binary system have been s tudied in thin films. Samples were prepared via sequential vacuum depositio n and annealing. Copper of 10-40 nm thick was deposited on glass substrates first, and indium deposition was followed. The In thicknesses were chosen so as to make the atomic concentration of In 0-75%. Physical properties bec ame stable after annealing at 120 degrees C for 10 min. The X-ray diffracti on pattern of the alloy film exhibited the C16 structure near the 65 at.% I n, suggesting the formation of the intermetallic compound CuIn2. Electrical properties of films were evaluated with Hall measurement. The resistivity of the ahoy film increased with In concentration, had a maximum at similar to 35 at.%, then decreased and showed a minimum at similar to 65 at.%, refl ecting the CuIn2 formation. Hall coefficient of alloy films was naturally n egative at low concentrations of In. However, the value gradually decreased to zero with the increase in In content and finally became positive above 40-50 at.% of In. From the temperature dependence of these electrical prope rties in the alloyed films, the co-existence of the 'hole'-like and 'electr on'-Iike electron orbits has been speculated. (C) 1998 Elsevier Science S.A . All rights reserved.