The growth of CoSi 2 thin film in Co/W/Si(100) multilayer structures

Abstract

The growth of a CoSi 2 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 N 2 (80%)+H 2 (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 ( R S) measurement and scanning electron microscopy (SEM). Using the deposited Co/Si(100) system as a reference point, a CoSi 2 layer was formed at 800 °C with undesirable crystalline structure and the R S value of about 1.6 Ω/□. Instead, for the Co/W/Si(100) system, it has been observed that CoSi 2 layer grown at about 900 °C has a nearly single crystalline structure with a dominant (200) texture and the R S value of about 1.0 Ω/□. The presence of a W interlayer between Co and Si causes the CoSi 2 layer to be thermally stable at high temperatures (900–1000 °C).