Solid state reactions of TaW thin films and Si single crystals

Abstract

Contact reactions between a Si substrate and thin films of TaW bilayers and codeposited alloys have been studied. The interdiffusion and silicide formation have been analysed by Auger electron spectroscopy and X-ray diffraction. In the bilayer structures the formation of TaSi 2 and WSi 2 is observed at 700–750°C and 800–850°C, respectively. For the Ta-rich alloy of Ta 80W 20, TaSi 2 is formed at 700–750°C similarly to the bilayer case, but this is followed by the formation of Ta 5 Si 3 which disappears at higher temperatures. For the W-rich alloy of Ta 20W 80, silicide formation is delayed to higher temperatures due to alloying in the thin film.