Variation of Microstructure and Electrical Conductivity of Amorphous AgInSbTe and SbTe Films during Crystallization

Abstract

Two kinds of chalcogenide films with similar Sb/Te atomic ratios, AgInSbTe (AIST) and SbTe (ST) were deposited on alkali-free glass using the RF sputtering method. The microstructure characteristics of both ST and AIST films were demonstrated to correlate with the electrical properties. TEM observation and GI-XRD profiles revealed that the structures of as-deposited AIST and ST films were amorphous characteristics. The sheet resistance of the as-deposited AIST films was twice as high as that of ST films and the effect of Ag and In additives was proposed. After annealing at 523 K for 1 h, the sheet resistance of both chalcogenide films decreased by four orders of magnitude due to crystallizations and the sheet resistance of crystallized AIST film was still twice as large as that of crystallized ST film. DSC measurement was used to determine the crystallization temperature of AIST films as 476 K and that of ST films as 445 K. The activation energies of crystallization were determined using Kissinger’s method, and 0.94 eV and 0.84 eV were obtained for AIST and ST films, respectively. TEM observations showed that AgSbTe₂ phase exists in the AIST film after heat treatment in addition to δ-Sb phase. No indium compounds were discovered in the AIST film by the energy dispersive spectroscopy (EDS) and XRD measurements.