Thermal stability of amorphous Zn-In-Sn-O films

Isochronal annealing of amorphous Zn and Sn codoped In2O3 (a-ZITO) films was performed at the Synchrotron so that to extract, in situ, important kinetic nucleation and growth parameters from a single constant-rate heating experiment. First, amorphous Zn and Sn codoped In2O3 films were deposited via pulsed laser deposition and subjected to postdeposition annealing treatments to study their stability against crystallization. Crystallization on glass and ĉ-sapphire occurred near the same temperature, however higher codoping levels resulted in increased crystallization temperatures. Postdeposition anneal crystallization temperatures were found to be higher than the substrate temperatures required to grow crystalline films during deposition. Then, a-ZITO films were subjected to a constant temperature ramp during in situ grazing-incidence X-ray diffraction experiments. Crystallization of films on both glass and ĉ-sapphire showed similar gradual crystallization behavior between 300 and 345 °C and strong (111) texturing, which suggests the influence of surface energy minimization during crystallization. The activation energy was found to be 2.87 eV using Johnson-MehlAvrami analysis. This work presents the advantages of in situ experiments to study nucleation and growth during crystallization of transparent conducting oxides.