Reaction mechanisms in aluminum-indium tin oxide ohmic contact metallization with Co and Ni barrier layers for active-matrix-display applications

Reaction mechanisms within aluminum-indium tin oxide (Al-ITO) metallization schemes were investigated in this work using Xray photoelectron spectrosco py and X-ray diffraction. Examination of A1-ITO, aluminum-nickel-indium tin oxide (Al-Ni-ITO), and aluminum-cobalt-indium tin oxide (Al-Co-ITO) interf aces reveals that considerable atomic rearrangement at the ITO interface wi th Al or with barrier layer transition (CO or Ni) metals occurs due to reac tion. Metal-oxygen bonds in crystalline ITO are broken and the interface is rearranged. In Al-Co-ITO stacks, reduced intermetallic species were detect ed at the Co-ITO interface. In Al-Ni-ITO stacks, such species were not dete cted at the Ni-ITO interface, although Al3Ni formed at the Al-Ni interface. These reactions within metallization stacks are important because they det ermine the electrical quality of ITO contacts with Al alloy data lines in p olysilicon thin film transistor displays. (C) 1999 The Electrochemical Soci ety. S0013-4651(98)08-069-0. All rights reserved.