Integrated system and method for source/drain engineering

Abstract

Implementations described herein generally provide a method of processing a substrate. Specifically, the methods described are used for cleaning and etching source/drain regions on a silicon substrate in preparation for precise Group IV source/drain growth in semiconductor devices. Benefits of this disclosure include precise fin size control in devices, such as 10 nm FinFET devices, and increased overall device yield. The method of integrated clean and recess includes establishing a low pressure processing environment in the processing volume, and maintaining the low pressure processing environment while flowing a first gas over a substrate in a processing volume, depositing a salt on the substrate, heating the processing volume to greater than 90° C., purging the processing volume with a second inert gas, and recessing a source/drain region disposed on the substrate.

1 . A method of processing a workpiece, comprising:
 flowing a first gas mixture into a processing chamber;   forming a first plasma from the first gas mixture;   exposing the workpiece to the first plasma, wherein the workpiece comprises:
 a substrate comprising a source/drain region; and 
 a fin layer extending from a surface of the source/drain region; and 
   depositing a salt on one or more surfaces of the source/drain region and the fin layer.   
     
     
         2 . The method of  claim 1 , wherein the first gas mixture comprises NH 3  and NF 3 . 
     
     
         3 . The method of  claim 1 , wherein source/drain region is disposed between a plurality of dielectric material features. 
     
     
         4 . The method of  claim 1 , further comprising:
 flowing a second gas mixture into the processing chamber before flowing the first gas mixture, the second gas mixture comprising hydrogen gas and argon gas;   forming a second plasma of the second gas mixture; and   exposing the workpiece to the second plasma before exposing the workpiece to the first plasma.   
     
     
         5 . The method of  claim 1 , wherein the fin layer comprises silicon. 
     
     
         6 . The method of  claim 1 , further comprising:
 heating the workpiece to about 90° C. or more; and   purging the processing chamber of the first gas mixture by flowing a purge gas mixture thereinto.   
     
     
         7 . The method of  claim 6 , wherein heating the workpiece to about 90° C. or more removes the salt or reaction byproducts of the salt from the one or more surfaces of the source/drain region and the fin layer. 
     
     
         8 . The method of  claim 7 , wherein depositing the salt and removing the salt or reaction byproducts of the salt cleans one or both of a native oxide or contaminates disposed on the one or more surfaces of the source/drain region and the fin layer. 
     
     
         9 . The method of  claim 8 , wherein the workpiece further comprises a dielectric material layer disposed on the fin layer. 
     
     
         10 . The method of  claim 9 , wherein the dielectric material layer is a dummy gate. 
     
     
         11 . The method of  claim 6 , further comprising:
 flowing an etchant gas mixture into the processing chamber;   forming an etching plasma from the etchant gas mixture; and   exposing the workpiece to the etching plasma to reduce a width of the fin layer.   
     
     
         12 . The method of  claim 11 , wherein exposing the workpiece to the etching plasma reduces the width of the fin layer by up to about 2 nm. 
     
     
         13 . The method of  claim 11 , wherein the etchant gas mixture comprises chlorine. 
     
     
         14 . The method of  claim 1 , further comprising:
 depositing an Si:As layer on one or more surfaces of the source/drain region.   
     
     
         15 . The method of  claim 14 , further comprising:
 depositing an Si:P layer on one or more surfaces of the source/drain region.   
     
     
         16 . A method of processing a substrate, comprising:
 flowing a first processing gas mixture comprising NH 3  and NF 3  into a processing chamber;   forming a first plasma from the first processing gas mixture;   exposing the substrate to the first plasma, wherein the substrate comprises:
 a source/drain region disposed between a plurality of dielectric material features; and 
 a fin layer extending from a surface of the source/drain region; 
   depositing a salt on one or more surfaces of the source/drain region and the fin layer; and   removing one or both of the salt or reaction byproducts of the salt from the one or more surfaces of the source/drain region and the fin layer, comprising:
 heating the substrate to 90° C. or more; and 
 purging the processing chamber of the first processing gas mixture by flowing a purging gas thereinto. 
   
     
     
         17 . The method of  claim 16 , wherein depositing the salt on the one or more surfaces of the source/drain region and the fin layer and removing one or both of the salt or reaction byproducts of the salt and the one or more surfaces of the source/drain region and the fin layer includes removing a native oxide layer formed on the one or more surfaces of the source/drain region and the fin layer. 
     
     
         18 . The method of  claim 16 , further comprising:
 flowing a second processing gas mixture comprising H 2  and Cl 2  into the processing chamber;   forming a second plasma from the second processing gas mixture; and   exposing the substrate to the second plasma.   
     
     
         19 . The method of  claim 18 , wherein exposing the substrate to the second plasma removes a material thickness of up to about 2 nm from the one or more surfaces of the source/drain region and the fin layer. 
     
     
         20 . The method of  claim 19 , further comprising:
 depositing an Si:P layer on one or more surfaces of the source/drain region.   
     
     
         21 . The method of  claim 5 , wherein the fin layer further comprises at least one of germanium, carbon, boron, and phosphorous.