Thermal Stability and Electrical Properties of Ag(Al) Metallization

Abstract

AbstractThe thermal stability and electrical resistivity of Ag(Al) alloy thin films on SiO2 are investigated and compared to pure Ag thin films by performing various analyses: Rutherford backscattering spectrometry (RBS), X-ray diffractometry (XRD), transmission electron microscopy (TEM), and four-point probe. The susceptibility to agglomeration of Ag on SiO2 layer is a drawback of Ag metallization. Ag(Al) thin films show good thermal stability on SiO2 layer without any diffusion barrier. The films are stable up to 600 °C for 1 hour in vacuum. Electrical resistivity of as-deposited Ag (5 at % Al) thin film is slightly higher than that of pure Ag thin film. However, the resistivity of Ag(Al) samples annealed at high temperatures (up to 600 °C for 1 hour in vacuum) remains constant due to the improvement of thermal stability (large reduction of agglomeration). This finding can impact metallization for thin film transistors (TFT) for displays, including flexible displays, and high-speed electronics due to lower resistivity value compared to Cu thin film.