Silicon nano wire having a silicon-nitride shell and method of manufacturing the same

Abstract

Silicon nano wires having silicon nitride shells and a method of manufacturing the same are provided. Each silicon nano wire has a core portion formed of silicon, and a shell portion formed of silicon nitride surrounding the core portion. The method includes removing silicon oxide formed on the shell of the silicon nano wire and forming a silicon nitride shell.

1 . A silicon nano wire comprising: 
 a core portion formed of silicon; and    a shell portion formed of silicon nitride surrounding the core portion.    
     
     
         2 . The silicon nano wire of  claim 1 , wherein the core portion is formed of amorphous silicon.  
     
     
         3 . The silicon nano wire of  claim 1 , wherein the core portion is formed of crystalline silicon.  
     
     
         4 . A silicon nano wire comprising: 
 a core portion formed of amorphous silicon in a linear shape; and    a shell portion formed of silicon nitride surrounding the core portion.    
     
     
         5 . The silicon nano wire of  claim 4 , wherein the silicon nitride shell is formed of Si 3 Ni 4 .  
     
     
         6 . A method of manufacturing a silicon nano wire, comprising: 
 forming a silicon nano wire having a silicon oxide shell;    removing the silicon oxide shell from the silicon nano wire to leave only a core portion; and    forming a silicon nitride shell.    
     
     
         7 . The method of  claim 6 , wherein the silicon oxide shell is removed by wet etching.  
     
     
         8 . The method of  claim 6 , wherein the silicon oxide shell is removed by dry etching.  
     
     
         9 . The method of  claim 6 , wherein the silicon nitride shell is formed by thermal nitridation.  
     
     
         10 . The method of  claim 6 , wherein the silicon nano wire having the silicon oxide shell is grown by a vapor-liquid-solid (VLS) mechanism.  
     
     
         11 . The method of  claim 6 , wherein the silicon nano wire having the silicon oxide shell is grown by a solid-liquid-solid (SLS) mechanism.  
     
     
         12 . The method of  claim 11 , wherein the growing of the silicon nano wire by the SLS mechanism comprises: 
 forming catalyst metal particles having a diameter of a few nanometers to a few tens of nanometers on a silicon substrate; and    growing the silicon nano wire on the silicon substrate by heating the substrate so the catalyst metal particles maintain a eutectic alloy state with silicon.    
     
     
         13 . The method of  claim 12 , wherein the forming of the catalyst metal particles comprises: 
 forming a catalyst metal thin film on the silicon substrate; and    forming the catalyst metal into particles by annealing the substrate.    
     
     
         14 . The method of claims of  12 , wherein the catalyst metal is a transition metal.  
     
     
         15 . The method of  claim 6 , wherein the forming of the silicon nitride shell comprises reducing the diameter of the core portion by growing the silicon nitride shell radially toward the center of the silicon nano wire.  
     
     
         16 . The method of  claim 6 , wherein the forming of the silicon nitride shell comprises supplying ammonia gas around the silicon nano wire while the silicon nano wire is heated.  
     
     
         17 . A method of manufacturing an amorphous silicon nano wire, comprising: 
 forming an amorphous silicon nano wire having a silicon oxide shell;    removing the silicon oxide shell from the amorphous silicon nano wire to leave only the core portion; and    forming a silicon nitride shell using thermal nitridation.    
     
     
         18 . The method of  claim 17 , wherein the forming of the amorphous silicon nano wire comprises: 
 forming a transition metal thin film on the silicon substrate;    forming transition metal particles having a diameter of a few nanometers to a few tens of nanometers by annealing the silicon substrate; and    growing the amorphous silicon nano wire on the silicon substrate while maintaining a eutectic alloy state of the transition metal particles and silicon by heating the substrate.    
     
     
         19 . The method of  claim 18 , wherein the growing of the amorphous silicon nano wire is performed by heating the silicon substrate to a temperature of 900 to 993° C.  
     
     
         20 . The method of  claim 17 , wherein the forming of the silicon nitride shell comprises reducing the diameter of the silicon core portion by growing the silicon nitride shell radially toward the center of the amorphous silicon nano wire.  
     
     
         21 . The method of  claim 17 , wherein the forming of the silicon nitride shell comprises supplying NH 3  gas around the amorphous silicon nano wire while the amorphous silicon nano wire is heated.  
     
     
         22 . A method of manufacturing silicon nano wires, comprising: 
 growing the silicon nano wires under a non-oxidative atmosphere; and    growing silicon nitride shells on the silicon nano wire using a thermal nitridation method under a non-oxidative atmosphere.