Retrograde doped layer for device isolation

Abstract

Embodiments herein provide device isolation in a complimentary metal-oxide fin field effect transistor. Specifically, a semiconductor device is formed with a retrograde doped layer over a substrate to minimize a source to drain punch-through leakage. A set of high mobility channel fins is formed over the retrograde doped layer, each of the set of high mobility channel fins comprising a high mobility channel material (e.g., silicon or silicon-germanium). The retrograde doped layer may be formed using an in situ doping process or a counter dopant retrograde implant. The device may further include a carbon liner positioned between the retrograde doped layer and the set of high mobility channel fins to prevent carrier spill-out to the high mobility channel fins.

1 . A method for forming a device, the method comprising:
 forming a retrograde doped layer over a substrate, the retrograde doped layer comprising one of:   doped silicon (Si), and doped silicon-germanium (Si—Ge);   forming a set of high mobility channel fins over the retrograde doped layer, wherein each of the set of high mobility channel fins comprises at least one of: Si, and Si—Ge, and a retrograde doped layer comprising one of: doped silicon (Si), and doped silicon-germanium (Si—Ge); and   forming a set of silicon fins adjacent the set of high mobility channel fins.   
     
     
         2 . The method according to  claim 1 , further comprising forming a carbon liner over the retrograde doped layer. 
     
     
         3 . The method according to  claim 1 , the forming the retrograde doped layer comprising performing an in situ doping process. 
     
     
         4 . The method according to  claim 3 , the forming the set of high mobility channel fins comprising:
 depositing the a high mobility channel material over the retrograde doped layer;   patterning the high mobility channel material, the retrograde doped layer, and the a substrate; and   etching the high mobility channel material, the retrograde doped layer, and the substrate.   
     
     
         5 . The method according to  claim 4 , the depositing comprising growing the high mobility channel material using a chemical vapor deposition of at least one of: Si, and Si—Ge. 
     
     
         6 . The method according to  claim 2 , the forming the retrograde doped layer comprising:
 forming an opening in the a substrate;   depositing the a high mobility channel material in the opening; and   performing a counter dopant retrograde implant to form the retrograde doped layer over the substrate in the opening.   
     
     
         7 . The method according to  claim 6 , further comprising performing a retrograde carbon implant to form the carbon liner over the retrograde doped layer. 
     
     
         8 . The method according to  claim 1 , the forming the retrograde doped layer comprising performing a counter dopant retrograde implant to form the retrograde doped layer within the a substrate. 
     
     
         9 . The method according to  claim 8 , further comprising:
 patterning an opening in a hardmask formed over the substrate prior to formation of the retrograde doped layer; and   performing a retrograde carbon implant to form the a carbon liner over the retrograde doped layer.   
     
     
         10 . A method for providing device isolation in a complementary metal-oxide semiconductor fin field effect transistor, the method comprising:
 forming a retrograde doped layer over a substrate, the retrograde doped layer comprising one of:   doped silicon (Si), and doped silicon-germanium (Si—Ge);   forming a set of high mobility channel fins over the retrograde doped layer, wherein each of the set of high mobility channel fins comprises at least one of: Si, and Si—Ge, and the retrograde doped layer comprising one of: doped silicon (Si), and doped silicon-germanium (Si—Ge); and   forming a set of silicon fins adjacent the set of high mobility channel fins.   
     
     
         11 . The method according to  claim 10 , further comprising forming a carbon liner over the retrograde doped layer. 
     
     
         12 . The method according to  claim 10 , the forming the retrograde doped layer comprising performing an in situ doping process. 
     
     
         13 . The method according to  claim 12 , the forming the set of high mobility channel fins comprising:
 depositing the a high mobility channel material over the retrograde doped layer;   patterning the high mobility channel material, the retrograde doped layer, and the a substrate; and   etching the high mobility channel material, the retrograde doped layer, and the substrate.   
     
     
         14 . The method according to  claim 13 , the depositing comprising growing the high mobility channel material using a chemical vapor deposition of at least one of: Si, and Si—Ge. 
     
     
         15 . The method according to  claim 11 , the forming the retrograde doped layer comprising:
 forming an opening in the a substrate;   depositing the a high mobility channel material in the opening; and   performing a counter dopant retrograde implant to form the retrograde doped layer over the substrate in the opening.   
     
     
         16 . The method according to  claim 15 , further comprising performing a retrograde carbon implant to form the carbon liner over the retrograde doped layer. 
     
     
         17 . The method according to  claim 10 , the forming the retrograde doped layer comprising performing a counter dopant retrograde implant to form the retrograde doped layer within the a substrate. 
     
     
         18 . The method according to  claim 17 , further comprising:
 patterning an opening in a hardmask formed over the substrate prior to formation of the retrograde doped layer; and   performing a retrograde carbon implant to form the carbon liner over the retrograde doped layer.   
     
     
         19 . A semiconductor device comprising:
 a retrograde doped layer formed over a substrate, the retrograde doped layer comprising one of:   doped silicon (Si), and doped silicon-germanium (Si—Ge);   a set of high mobility channel fins formed over the retrograde doped layer, wherein each of the set of high mobility channel fins comprises at least one of: Si, and Si—Ge, and a retrograde doped layer comprising one of: doped silicon (Si), and doped silicon-germanium (Si—Ge); and   a set of silicon fins adjacent the set of high mobility channel fins.   
     
     
         20 . The semiconductor device according to  claim 19 , further comprising a carbon liner formed over the retrograde doped layer, wherein the set of high mobility channel fins and the set of silicon fins are formed over the carbon liner.