Process for Structuring Silicon

Abstract

A process for etching a silicon-containing substrate to form structures is provided. In the process, a metal is deposited and patterned onto a silicon-containing substrate (commonly one with a resistivity above 1-10 ohm-cm) in such a way that the metal is present and touches silicon where etching is desired and is blocked from touching silicon or not present elsewhere. The metallized substrate is submerged into an etchant aqueous solution comprising about 4 to about 49 weight percent HF and an oxidizing agent such as about 0.5 to about 30 weight percent H 2 O 2 , thus producing a metallized substrate with one or more trenches. A second silicon etch is optionally employed to remove nanowires inside the one or more trenches.

1 . A silicon substrate having an etched pattern which comprises features that have an aspect ratio larger than about 80:1, smooth sidewalls without a zigzag pattern, and features arranged along more than one crystallographic direction. 
     
     
         2 . A substrate as described in  claim 1 , wherein a bottom of the etched pattern is coated with silver metal. 
     
     
         3 . A substrate as described in  claim 1 , wherein the minimum dimension of the features in the etched pattern is greater than about 100 nm. 
     
     
         4 . A substrate as described in  claim 1 , wherein the minimum dimension of the features in the etched pattern is less than about 100 nm. 
     
     
         5 . A substrate as described in  claim 4 , wherein either a width or a length of the etched pattern is below the coherence length of electrons or holes in silicon. 
     
     
         6 . A substrate as described in  claim 4 , wherein either a width or a length of the etched pattern is below the de Broglie wavelength of electrons or holes in silicon.