Arrays of high-aspect-ratio germanium nanostructures with nanoscale pitch and methods for the fabrication thereof

Abstract

Methods for fabricating thin, high-aspect-ratio Ge nanostructures from high-quality, single-crystalline Ge substrates are provided. Also provided are grating structures made using the methods. The methods utilize a thin layer of graphene between a surface of a Ge substrate, and an overlying resist layer. The graphene passivates the surface, preventing the formation of water-soluble native Ge oxides that can result in the lift-off of the resist during the development of the resist.

What is claimed is: 
     
         1 . A grating structure comprising:
 a substrate; and   a plurality of single-crystalline germanium fins on a surface of the substrate, the germanium fins having widths in the range from 5 nm to 50 nm and aspect ratios in the range from 5 to 10.   
     
     
         2 . The grating structure of  claim 1 , wherein the germanium fins are arranged in parallel on the surface of the substrate. 
     
     
         3 . The grating structure of  claim 2 , wherein the germanium fins have widths of less than 40 nm and aspect ratios of at least 6. 
     
     
         4 . The grating structure of  claim 2 , wherein the germanium fins have a pitch of 100 nm or less. 
     
     
         5 . The grating structure of  claim 4 , wherein the germanium fins have a pitch in the range from 20 nm to 100 nm. 
     
     
         6 . The grating structure of  claim 1 , wherein the germanium fins form a non-epitaxial interface with the surface of the substrate. 
     
     
         7 . The grating structure of  claim 6 , wherein the substrate is a silicon substrate. 
     
     
         8 . The grating structure of  claim 1  comprising at least ten germanium fins. 
     
     
         9 . The grating structure of  claim 1 , wherein the germanium fins have widths in the range from 10 nm to 50 nm. 
     
     
         10 . A germanium fin field effect transistor comprising:
 a substrate;   a plurality of germanium fins arranged in parallel along their lengths on a surface of the substrate, each fin in the plurality having a base, a top, and two opposing side-walls, wherein the germanium fins have widths in the range from 5 nm to 50 nm and aspect ratios in the range from 5 to 10;   a dielectric material that provides lateral electrical isolation of the germanium fins;   a gate wrapped around the top and the two opposing side-walls of each germanium fin; and   a gate dielectric disposed between the gate and the germanium fins.