Tisin coating method

Abstract

A method for ALD coating of a substrate with a layer containing Ti, Si, N, wherein a reaction gas and then a flushing gas are introduced into a process chamber holding the substrate in a plurality of successive steps, each in one or more cycles, wherein TiN is deposited in a first step with a reaction gas containing Ti and a reaction gas containing N, TiSi is deposited in a second step with a reaction gas containing Ti and a reaction gas containing Si, and in a third step following the second step, TiSiN is deposited with a reaction gas containing Ti, with a reaction gas containing N and with a reaction gas containing Si.

1 . A method for forming a contact structure of a semiconductor device the method comprising:
 providing in a reaction chamber a substrate comprising an exposed silicon surface;   forming a conductive diffusion barrier on the exposed silicon surface by cyclic thermal deposition, forming the conductive diffusion barrier comprising:
 forming a nitrogen-free high conductivity region by alternatingly exposing the substrate to a first titanium-containing precursor and a first silicon-containing precursor; and 
 forming a nitrogen-containing high diffusion barrier region on the high conductivity region by alternatingly exposing the substrate to a second titanium-containing precursor, a nitrogen-containing precursor and a second silicon-containing precursor. 
   
     
     
         2 . The method of  claim 1 , wherein the exposed silicon surface is a polysilicon surface. 
     
     
         3 . The method of  claim 2 , wherein forming the high conductivity region comprises forming a titanium silicide (TiSi 2 ) layer. 
     
     
         4 . The method of  claim 3 , wherein forming the high diffusion barrier region comprises forming a titanium silicon nitride (TiSiN) layer. 
     
     
         5 . The method of  claim 4 , wherein forming the TiSiN layer comprises directly contacting the TiSi 2  layer with the TiSiN without an intervening layer. 
     
     
         6 . The method of  claim 5 , wherein forming the TiSiN layer comprises forming a plurality of TiN sublayers alternating with a plurality of Si sublayers. 
     
     
         7 . The method of  claim 6 , wherein forming the TiSiN layer comprises forming the TiN sublayers and the Si sublayers that are intermixed to form a homogeneous layer. 
     
     
         8 . The method of  claim 6 , wherein forming the TiSiN layer comprises forming the TiN sublayers and the Si sublayers that remain as discrete and alternating layers. 
     
     
         9 . The method of  claim 8 , wherein forming the TiSiN layer comprises forming a first one of the TiN sublayers to contact the TiSi 2  layer. 
     
     
         10 . The method of  claim 8 , wherein forming the TiSiN layer comprises terminating with a Si layer that is free of nitrogen. 
     
     
         11 . The method of  claim 10 , further comprising forming a metallic layer on the Si layer to form the contact structure. 
     
     
         12 . The method of  claim 4 , further comprising forming a TiN layer interposed between the polysilicon surface and the TiSi 2  layer. 
     
     
         13 . A method for forming a contact structure of a semiconductor device, the method comprising:
 forming a nitrogen-free high conductivity region on a silicon surface by alternatingly exposing the substrate to a first titanium-containing precursor and a first silicon-containing precursor; and   forming a nitrogen-containing high diffusion barrier region on the high conductivity region, forming the high diffusion barrier region comprising:
 alternatingly exposing the substrate to a second titanium-containing precursor and a nitrogen-containing precursor to form a TiN sublayer, and 
 exposing the substrate to a second silicon-containing precursor to form a Si sublayer. 
   
     
     
         14 . The method of  claim 13 , wherein the silicon surface is a polysilicon surface. 
     
     
         15 . The method of  claim 13 , wherein forming the high conductivity region forms a titanium silicide (TiSi 2 ) layer. 
     
     
         16 . The method of  claim 13 , wherein forming the high diffusion barrier region comprises forming a plurality of TiN sublayers alternating with a plurality of Si sublayers to form a titanium silicon nitride (TiSiN) layer. 
     
     
         17 . The method of  claim 16 , wherein forming the TiSiN layer comprises forming a homogeneous TiSiN. 
     
     
         18 . The method  claim 17 . wherein forming the TiSiN layer comprises forming a plurality of discrete TiN sublayers alternating with a plurality of discrete Si sublayers. 
     
     
         19 . The method of  claim 18 , wherein the TiSiN layer terminates with a Si layer that is free of nitrogen. 
     
     
         20 . The method of  claim 19 , further comprising forming a metallic layer on the Si layer to form the contact structure.