Etching solution for wet chemical pyramidal texture etching of silicon surfaces

Abstract

A new and improved etching solution and etching method provide wet chemical pyramidal texture etching of (100) silicon surfaces. A uniform and completely pyramidal texture etching of silicon surfaces is achieved with an etching solution including water, an alkaline reagent, and isopropanol together with an aqueous alkaline ethylene glycol solution.

What is claimed is:  
     
         1 . A free-standing etching solution for the wet chemical pyramidal texture etching of silicon surfaces comprising: water, an alkaline reagent, isopropanol and an aqueous alkaline ethylene glycol solution.  
     
     
         2 . The free-standing etching solution as in  claim 1 , wherein the etching solution further comprises silicate.  
     
     
         3 . The free-standing etching solution as in  claim 1 , wherein the etching solution contains 0.5 to 5 vol % isopropanol.  
     
     
         4 . The free-standing etching solution as in  claim 1 , wherein the proportion of isopropanol present in the etching solution is greater than the proportion of ethylene glycol.  
     
     
         5 . The free-standing etching solution as in  claim 4 , wherein the ratio of isopropanol the ethylene glycol is at maximum 1:1.  
     
     
         6 . The free-standing etching solution as in  claim 1 , wherein the aqueous alkaline ethylene glycol solution is reacted with oxygen.  
     
     
         7 . A free-standing etching solution for the wet chemical pyramidal texture etching of silicon surfaces comprising: water, sodium or potassium hydroxide, isopropanol and an aqueous alkaline ethylene glycol solution.  
     
     
         8 . The free-standing etching solution as in  claim 7 , further comprising silicate.  
     
     
         9 . The free-standing etching solution as in  claim 7 , wherein the etching solution contains 0.5 to 5 vol. % isopropanol.  
     
     
         10 . The free-standing etching solution as in  claim 7 , wherein the proportion of isopropanol present in the etching solution is greater than the proportion of ethylene glycol.  
     
     
         11 . The free-standing etching solution as in  claim 10 , wherein the ratio of isopropanol to ethylene glycol is at maximum 1:1.  
     
     
         12 . The free-standing etching solution as in  claim 7 , wherein the aqueous alkaline ethylene glycol solution is reacted with oxygen.