Selective area growth carbon nanotubes by metal imprint method

Abstract

Manufacturing methods of using a metal imprint technique for growing carbon nanotubes on selective areas and the structures formed thereof are provided. One of the manufacturing methods includes steps of forming a first substrate with tapered structures applied with a metal catalyst, imprinting a second substrate on the first substrate for being a growth substrate, and growing carbon nanotubes on the growth substrate. The other manufacturing method includes steps of forming a first substrate with tapered structures, imprinting the first substrate on a second substrate applied with a metal catalyst for forming a second growth substrate, and growing carbon nanotubes on the second grown substrate. And, the formed structures of the present invention include a substrate, plural carbon nanotubes, and plural imprinted vestiges.

1 . A method for growing a plurality of carbon nanotubes on a selective area, comprising steps of: 
 a) forming a first masking layer on a first substrate;    b) photolithographing said first masking layer for forming a plurality of specific areas on said first substrate;    c) etching said plurality of specific areas for forming a second masking layer on said first substrate;    d) etching said second masking layer and said first substrate for forming a plurality of tapered structures;    e) applying a catalyst on said plurality of tapered structures;    f) imprinting a second substrate on said first substrate having said catalyst thereon for being a growth substrate with a plurality of vestiges of said catalyst; and    g) growing said plurality of carbon nanotubes on said growth substrate.    
     
     
         2 . The method as claimed in  claim 1 , wherein both said first substrate and said second substrate are silicon substrates.  
     
     
         3 . The method as claimed in  claim 1 , wherein said first masking layer is a first silicon oxide masking layer formed at a temperature ranged from 800 to 1200° C. and has a thickness ranged from 2000 to 7000 Å.  
     
     
         4 . The method as claimed in  claim 1 , wherein said step c) is performed by a BOE (Buffer Oxide Etching) solution containing a hydrofluoric acid.  
     
     
         5 . The method as claimed in  claim 1 , wherein said step d) is performed by a chemical solution containing a potassium hydroxide.  
     
     
         6 . The method as claimed in  claim 1 , wherein said step e) is performed by a physical deposition method.  
     
     
         7 . The method as claimed in  claim 1 , wherein said second masking layer is formed just on said plurality of specific areas.  
     
     
         8 . The method as claimed in  claim 1 , wherein said plurality of tapered structures are a plurality of sharp silicon structures.  
     
     
         9 . The method as claimed in  claim 1 , wherein said step b) further comprises steps of: 
 b1) providing a mask;    b2) forming a first photoresist layer on said first masking layer; and    b3) etching said first photoresist layer with said mask for forming a second photoresist layer.    
     
     
         10 . The method as claimed in  claim 9 , wherein said second masking layer comprises said second photoresist layer and a second silicon oxide masking layer.  
     
     
         11 . The method as claimed in  claim 10 , wherein said step c) further comprises a step of c1) removing said second photoresist layer by an acetone.  
     
     
         12 . The method as claimed in  claim 1 , wherein said catalyst is a metal catalyst selected from a group consisting of a ferrum, a cobalt, and a nickel.  
     
     
         13 . The method as claimed in  claim 1 , wherein each of said plurality of vestiges of said catalyst has a diameter ranged from 10 to 200 nanometers.  
     
     
         14 . The method as claimed in  claim 13 , wherein each of said plurality of vestiges of said catalyst introduces a growth of each of said carbon nanotubes.  
     
     
         15 . A method for growing a plurality of carbon nanotubes on a selective area, comprising steps of: 
 a) forming a first masking layer on a first substrate;    b) photolithographing said first masking layer for forming a plurality of specific areas on said first substrate;    c) etching said plurality of specific areas for forming a second masking layer on said first substrate;    d) etching said second masking layer and said first substrate for forming a plurality of tapered structures on said first substrate;    e) applying a catalyst on a second substrate;    f) imprinting said first substrate on said second substrate for respectively obtaining a residuum on a tip of each of said plurality of tapered structures; and    g) respectively growing each of said carbon nanotubes on each of said plurality of tapered structures having said residuum.    
     
     
         16 . The method as claimed in  claim 15 , wherein said catalyst is a metal catalyst selected from a group consisting of a ferrum, a cobalt, and a nickel.  
     
     
         17 . The method as claimed in  claim 15 , wherein said step b) further comprises steps of: 
 b1) providing a mask;    b2) forming a first photoresist layer on said first masking layer; and    b3) etching said first photoresist layer with said mask for forming a second photoresist layer.    
     
     
         18 . A method for growing a plurality of carbon nanotubes, comprising steps of: 
 a) providing a first substrate having a plurality of tapered structures;    b) applying a catalyst on said plurality of tapered structures;    c) imprinting a second substrate on said first substrate for obtaining a plurality of vestiges of said catalyst on said second substrate; and    d) growing said plurality of carbon nanotubes on said plurality of vestiges.    
     
     
         19 . The method as claimed in  claim 18 , wherein said catalyst is a metal catalyst selected from a group consisting of a ferrum, a cobalt, and a nickel.  
     
     
         20 . A carbon nanotube structure, comprising: 
 a silicon substrate;    at least an imprinted vestige deposited on said silicon substrate; and    at least a carbon nanotube grown on said imprinted vestige.    
     
     
         21 . The structure as claimed in  claim 20 , wherein said imprinted vestige is formed by a metal imprint technique.  
     
     
         22 . A carbon nanotube structure, comprising: 
 a silicon substrate with a plurality of tapered structures; and    a plurality of carbon nanotubes respectively grown on a tip of each of said plurality of tapered structures.    
     
     
         23 . The structure as claimed in  claim 22 , wherein said plurality of carbon nanotubes are grown along a same direction.  
     
     
         24 . The structure as claimed in  claim 22 , wherein said plurality of tapered structures are formed by steps of a photolithography, a first etching, and a second etching.  
     
     
         25 . The structure as claimed in  claim 22 , wherein said plurality of carbon nanotubes are introduced to grow by a metal catalyst.