Characterization of silver selenide thin films grown on Cr-covered Si substrates

Abstract

Thermal stability of silver selenide thin films formed from the solid-state reaction of Ag-Se diffusion couples on Si substrates covered with a thin Cr film, is investigated. Glancing angle X-ray diffraction (GXRD), XPS, atomic force microscopy (AFM) and Rutherford backscattering spectrometry (RBS) are used to characterize the as-deposited films and those annealed at 100, 200, 300, and 400 °C. The results reveal the formation of polycrystalline orthorhombic silver selenide films that remain stable without compositional change upon thermal annealing, in marked contrast to the agglomeration exhibited by silver selenide films deposited on Si without Cr film. The improvement in the thermal stability is attributed to compressive stress relief by a grainy morphology with large surface area, the formation of which is promoted by partially oxidized Cr adhesion film.