Dry etch method for texturing silicon and device

Abstract

A method for texturing silicon includes loading a silicon wafer into a vacuum chamber, heating the silicon wafer and thermal cracking a gas to generate cracked sulfur species. The silicon wafer is exposed to the cracked sulfur species for a time duration in accordance with a texture characteristic needed for a surface of the silicon wafer.

1 .- 14 . (canceled) 
     
     
         15 . A photovoltaic device, comprising:
 a textured silicon substrate including pyramidal shaped recesses formed in a surface thereof, the pyramidal shaped recesses including exposed (111) silicon surfaces;   a junction layer formed in accordance with the textured silicon substrate;   a first electrode layer formed in contact with the silicon substrate; and   a second electrode layer formed over the junction layer.   
     
     
         16 . The device as recited in  claim 15 , wherein the pyramidal shaped recesses are formed by exposing the silicon wafer to cracked sulfur species to etch the wafer to expose the (111) silicon surfaces. 
     
     
         17 . The device as recited in  claim 15 , wherein the pyramidal shaped recesses are randomly located across the surface. 
     
     
         18 . The device as recited in  claim 15 , wherein the pyramidal shaped recesses formed in the wafer have a depth of between about 10 nm and about 300 nm. 
     
     
         19 . The device as recited in  claim 15 , wherein the pyramidal shaped recesses formed in the wafer have a size of between about 20 nm and about 100 nm. 
     
     
         20 . The device as recited in  claim 15 , wherein the junction layer include one of a p-i-n stack, n-i-p stack, a p-n junction or n-p junction.