Methods of forming metastable replacement fins for a finfet semiconductor device by performing a replacement growth process

Abstract

Various methods are disclosed herein for forming alternative fin materials that are in a stable or metastable condition. In one case, a metastable replacement fin is grown to a height that is greater than an unconfined stable critical thickness of the replacement fin material and it has a defect density of 10 5 defects/cm 2 or less throughout at least 90% of its entire height. In another case, a metastable replacement fin is grown to a height that is greater than an unconfined metastable critical thickness of the replacement fin material and it has a defect density of 10 5 defects/cm 2 or less throughout at least 90% of its entire height.

What is claimed: 
     
         1 . A method, comprising:
 forming a trench in a layer of insulating material that is positioned above a substrate comprised of a first semiconductor material, said trench exposing a surface of said substrate and said trench having a width at a bottom of said trench that is less than or equal to 20 nm and a depth that is 60 nm or less; and   performing an epitaxial deposition process to form a metastable replacement fin material in said trench above said exposed surface of said substrate, wherein said replacement fin has a height that is 60 nm or less and it is partially strained in a direction that corresponds to an axial length direction of said replacement fin, wherein said replacement fin is comprised of a second semiconductor material that is different than said first semiconductor material and wherein said replacement fin material has a defect density of 10 5  defects/cm 2  or less throughout at least 90% of its entire height.   
     
     
         2 . The method of  claim 1 , wherein said replacement fin material futher comprises a defect-containing interface region in contact with said substrate that has a defect density greater than 10 5  defects/cm 2 . 
     
     
         3 . The method of  claim 1 , wherein said height of said replacement fin is greater than an unconfined metastable critical thickness of said second semiconductor material. 
     
     
         4 . The method of  claim 1 , wherein said replacement fin is substantially strain-free in directions that correspond to a height direction and a lateral width direction of said replacement fin. 
     
     
         5 . The method of  claim 1 , wherein said exposed surface of said substrate is an exposed upper surface of a substrate fin. 
     
     
         6 . A method, comprising:
 forming a trench in a layer of insulating material that is positioned above a substrate comprised of a first semiconductor material, said trench exposing a surface of said substrate and said trench having a width at a bottom of said trench that is less than or equal to 20 nm; and   performing an epitaxial deposition process to form a metastable replacement fin material above said exposed surface of said substrate, wherein said replacement fin is comprised of a second semiconductor material that is different than said first semiconductor material, and wherein said replacement fin has a height that is greater than an unconfined metastable critical thickness of said second semiconductor material and wherein said replacement fin has a defect density of 10 5  defects/cm 2  or less throughout at least 90% of its entire height.   
     
     
         7 . The method of  claim 6 , wherein said replacement fin is partially strained in a direction that corresponds to an axial length direction of said replacement fin. 
     
     
         8 . The method of  claim 7 , wherein said replacement fin is substantially strain-free in directions that correspond to a height direction and a lateral width direction of said replacement fin. 
     
     
         9 . The method of  claim 6 , wherein said replacement fin material further comprises a defect-containing interface region in contact with said substrate that has a defect density greater than 10 5  defects/cm 2 . 
     
     
         10 . The method of  claim 6 , wherein said exposed surface of said substrate is an exposed upper surface of a substrate fin. 
     
     
         11 . A method, comprising:
 forming a trench in a layer of insulating material that is positioned above a substrate comprised of a first semiconductor material, said trench exposing a surface of said substrate and said trench having a width at a bottom of said trench that is less than or equal to 20 nm; and   performing an epitaxial deposition process to form a metastable replacement fin material above said exposed surface of said substrate, wherein said replacement fin is comprised of a second semiconductor material that is different than said first semiconductor material, wherein said replacement fin:
 is partially strained in a direction that corresponds to an axial length direction of said replacement fin; 
 has a height that is greater than an unconfined metastable critical thickness of said second semiconductor material; 
 has a defect density of 10 5  defects/cm 2  or less throughout at least 90% of its entire height; and 
 comprises a defect-containing interface region in contact with said substrate that has a defect density greater than 10 5  defects/cm 2 . 
   
     
     
         12 . The method of  claim 11 , wherein said replacement fin is substantially strain-free in directions that correspond to a height direction and a lateral width direction of said replacement fin. 
     
     
         13 . The method of  claim 11 , wherein said exposed surface of said substrate is an exposed upper surface of a substrate fin.