Low Temperature Silicides for Poly-Silicon Thin Film Transistor Applications

Abstract

AbstractThin films of cobalt, nickel, and tungsten were sputtered on three types of silicon materials to explore their potential for use as silicides in thin film transistor technologies for active matrix liquid crystal displays. The metals were sputtered onto single-crystal, polycrystalline, and amorphous silicon. The metals were annealed in vacuum after deposition over temperatures ranging from 250°C to 750°C. The sheet resistance of the resulting silicide films was measured using a four point probe apparatus. Cobalt silicides with sheet resistance of less than 4 Ω/ were formed at 600°C. Nickel produced films with sheet resistance below 10 Ω/▪ at 350°C, though the surface was required to be vacuum-clean. In this study, tungsten did not produce silicides. Surface preparation has been found to be an important factor in tungsten and nickel silicidation.