Multi-region diffusion barrier containing titanium, silicon and nitrogen

A method of forming an electrically conductive diffusion barrier, the method comprising:

• providing a substrate comprising an exposed silicon surface formed of monocrystalline silicon or polycrystalline silicon in a reaction chamber;
• forming a first region directly on the exposed silicon surface by exposing the substrate first to a titanium precursor, followed by alternatingly exposing the substrate to a nitrogen precursor and the titanium precursor;
• forming a second region over the first region by exposing the substrate to a silicon precursor;
• and
• forming a third region comprising TiSiN over the second region by alternatingly exposing the substrate to the titanium precursor and the nitrogen precursor to form TiN, followed by exposing the substrate to the silicon precursor,
• wherein a combined thickness of the first to third regions does not exceed 10 nm.

A method of forming an electrically conductive diffusion barrier, the method comprising:

• providing a substrate comprising an exposed silicon surface formed of monocrystalline silicon or polycrystalline silicon in a reaction chamber;
• forming a first region directly on the exposed silicon surface of the substrate by alternatingly exposing the substrate to a titanium precursor and a nitrogen precursor;
• forming a second region over the first region by exposing the substrate to a silicon precursor;
• and
• forming a third region comprising TiSiN over the second region by alternatingly exposing the substrate to the titanium precursor and the nitrogen precursor to form TiN, followed by exposing the substrate to the silicon precursor,
• wherein forming the first to third regions comprises thermally reacting respective precursors without using plasma.