The growth of CoSi2 thin film in Co/W/Si(100) multilayer structures

The growth of a CoSi2 thin film has been studied for the Co/W/Si(100) system. The Co film with a thickness of about 30 nm was grown over 12 nm sputtered W interlayer using the evaporation technique. The deposited multilayer structure was annealed in an N2 (80%)+H2 (20%) environment in a temperature range from 400 to 1000 °C for 60 min. The samples were characterized by X-ray diffraction (XRD), four point probe sheet resistance (RS) measurement and scanning electron microscopy (SEM). Using the deposited Co/Si(100) system as a reference point, a CoSi2 layer was formed at 800 °C with undesirable crystalline structure and the RS value of about 1.6 Ω/□. Instead, for the Co/W/Si(100) system, it has been observed that CoSi2 layer grown at about 900 °C has a nearly single crystalline structure with a dominant (200) texture and the RS value of about 1.0 Ω/□. The presence of a W interlayer between Co and Si causes the CoSi2 layer to be thermally stable at high temperatures (900–1000 °C).