Nucleation method for atomic layer deposition of cobalt on bare silicon during the formation of a semiconductor device

摘要

A method used to form a cobalt metal layer on a silicon surface using an atomic layer deposition (ALD) process comprises a treatment of the silicon surface prior to cobalt formation. Treatment includes serial exposure to one or more cycles comprising a titanium nitride precursor or a tantalum nitride precursor, followed by an optional exposure to ammonia. After this treatment, the silicon surface is exposed to a metal organic cobalt such as cyclopentadienylcobalt dicarbonyl to form a cobalt precursor on the silicon surface, which is then exposed to hydrogen or ammonia to reduce the precursor to an ALD cobalt metal layer. Once this initial metal layer is formed, additional cobalt ALD layers may be completed to form a cobalt metal layer of a desired thickness.