Methods For Forming Cobalt Layers Including Introducing Vaporized Cobalt Precursors And Methods For Manufacturing Semiconductor Devices Using The Same

Abstract

The present invention provides methods for forming cobalt silicide layers, including introducing a vaporized cobalt precursor onto a silicon substrate to form a cobalt layer. The vaporized cobalt precursor has the formula Co 2 (CO) 6 (R 1 —C≡C—R 2 ), wherein R 1 is H or CH 3 , and R 2 is H, t-butyl, methyl or ethyl. The silicon substrate is thermally treated so that silicon is reacted with cobalt to form a cobalt silicide layer. Methods for manufacturing semiconductor devices including the cobalt silicide layers described herein and such devices are also provided.

1 . A method of manufacturing a semiconductor device comprising: 
 forming a gate structure including a gate oxide layer pattern and a polysilicon layer pattern on a silicon substrate;    forming a nitride spacer on a sidewall of the gate structure;    forming source/drain regions at surface portions of the silicon substrate that are positioned at both sides of the gate structure;    introducing a vaporized cobalt precursor having a formula Co 2 (CO) 6 (R 1 —C≡C—R 2 ), wherein R 1  is H or CH 3 , and R 2  is H, t-butyl, methyl or ethyl, onto the silicon substrate to form a cobalt layer on a native oxide layer that is naturally formed on the silicon substrate;    forming a titanium layer on the cobalt layer; and    thermally treating the silicon substrate to diffuse titanium into the native oxide layer to reduce the native oxide layer and/or to react silicon with cobalt to form a cobalt silicide (CoSi 2 ) layer on the gate structure and the source/drain regions.    
   
   
       2 . The method of  claim 1 , wherein the titanium layer is formed by a chemical vapor deposition (CVD) process, an atomic layer deposition (ALD) process or a physical vapor deposition (PVD) process.  
   
   
       3 . The method of  claim 1 , wherein the titanium has a thickness at least about 5 Å.  
   
   
       4 . The method of  claim 1 , further comprising forming a titanium nitride layer on the titanium layer.  
   
   
       5 . The method of  claim 1 , wherein the titanium nitride layer has a thickness at least about 100 Å.  
   
   
       6 . The method of  claim 1 , wherein the cobalt precursor comprises Co 2 (CO) 6 :(HC≡CtBu), Co(MeCp) 2 , Co(CO) 3 (NO), Co(CO) 2  Cp, CoCp 2 , Co 2 (CO) 6 : (HC≡CPh), Co 2 (CO) 6 :(HC≡CH), Co 2 (CO) 6 :(HC≡CCH 3 ), Co 2 (CO) 6 :(CH 3 C≡CCH 3 ) or a mixture thereof.  
   
   
       7 . The method of  claim 1 , wherein the cobalt precursor comprises dicobalt hexacarbonyl t-butyl acetylene.  
   
   
       8 . The method of  claim 1 , wherein the silicon substrate is thermally treated in a furnace or subjected to a rapid thermal process (RTP).  
   
   
       9 . The method of  claim 1 , wherein thermally treating the silicon substrate comprises: 
 performing a first thermal treatment of the silicon substrate in an atmosphere having a temperature in a range of about 300° C. to about 600° C. to convert the cobalt layer into an initial cobalt silicide layer by partially reacting silicon and cobalt; and    at least partially removing the titanium layer and un-reacted cobalt remaining on the substrate.    
   
   
       10 . The method of  claim 9  further comprising performing a second thermal treatment of the silicon substrate in an atmosphere having a temperature in a range of about 700° C. to about 1,000° C. to form a final cobalt silicide.  
   
   
       11 . The method of  claim 9 , wherein the final cobalt silicide layer has a low resistance, improved stability and/or improved step coverage relative to the initial cobalt silicide layer.  
   
   
       12 . The method of  claim 9 , wherein the titanium layer and un-reacted cobalt remaining on the substrate are substantially removed.  
   
   
       13 . The method of  claim 1 , wherein the cobalt silicide layer extends into the silicon substrate less than a junction depth of the source/drain regions.  
   
   
       14 . A method of manufacturing a semiconductor device comprising: 
 forming a polysilicon layer on a silicon substrate;    forming an insulating interlayer on the polysilicon layer;    etching the insulating interlayer to form a contact hole partially exposing the polysilicon layer;    introducing a vaporized cobalt precursor having a formula Co 2 (CO) 6 (R 1 —C≡C—R  2 ), wherein R 1  is H or CH 3 , and R 2  is H, t-butyl, methyl or ethyl, onto the silicon substrate to form a cobalt layer on a native oxide layer that is naturally formed on the silicon substrate;    forming a titanium layer on the cobalt layer; and    thermally treating the silicon substrate to diffuse titanium into the silicon substrate and the cobalt silicide layer.    
   
   
       15 . The method of  claim 14 , wherein the titanium reduces the formation of an oxide layer at an interface between the silicon substrate and the cobalt silicide layer.  
   
   
       16 . The method of  claim 14 , wherein the contact hole is cleaned using a plasma treatment comprising hydrogen gas.