Etchant for controlled etching of ge and ge-rich silicon germanium alloys

Abstract

The present disclosure provides a chemical etchant which is capable of removing Ge and Ge-rich SiGe alloys in a controlled manner. The chemical etchant of the present disclosure includes a mixture of a halogen-containing acid, hydrogen peroxide, and water. Water is present in the mixture in an amount of greater than 90% by volume of the entire mixture. The present disclosure also provides a method of making such a chemical etchant. The method includes mixing, in any order, a halogen-containing acid and hydrogen peroxide to provide a halogen-containing acid/hydrogen peroxide mixture, and adding water to the halogen-containing acid/hydrogen peroxide mixture. Also disclosed is a method of etching a Ge or Ge-rich SiGe alloy utilizing the chemical etchant of the present application.

1 . A chemical etchant for etching of Ge or a Ge-rich SiGe alloy in a controlled manner, said chemical etchant comprising a mixture of a halogen-containing acid, hydrogen peroxide, and water, wherein the water is present in an amount of greater than 90% by volume of the total mixture. 
     
     
         2 . The chemical etchant of  claim 1  wherein said halogen-containing acid comprises hydrofluoric (HF) acid, hydrochloric (HCl) acid, hydrobromic (HBr) acid, hydriodic (HI) acid or any mixtures thereof. 
     
     
         3 . The chemical etchant of  claim 2  wherein said halogen-containing acid is hydrofluoric (HF) acid. 
     
     
         4 . The chemical etchant of  claim 1  wherein said halogen-containing acid, said hydrogen peroxide and said water are present in a ratio from 1:15:150 to 1:15:10000 
     
     
         5 . The chemical etchant of  claim 1  wherein said halogen-containing acid, said hydrogen peroxide and said water are present in a ratio from 1:15:500 to 1:15:2000 
     
     
         6 . The chemical etchant of  claim 1  wherein said amount of water is greater than 98% by volume of the total mixture. 
     
     
         7 . The chemical etchant of  claim 1  wherein said water is deionized water. 
     
     
         8 . A chemical etchant for etching of Ge or a Ge-rich SiGe alloy in a controlled manner, said chemical etchant consisting essentially of a mixture of a halogen-containing acid, hydrogen peroxide, and water, wherein the water is present in an amount of greater than 90% by volume of the total mixture. 
     
     
         9 . The chemical etchant of  claim 8  wherein said halogen-containing acid is hydrofluoric (HF) acid. 
     
     
         10 . A method of making a chemical etchant for etching of Ge or a Ge-rich SiGe alloy in a controlled manner, said method comprising:
 mixing, in any order, a halogen-containing acid and hydrogen peroxide to provide a halogen-containing acid/hydrogen peroxide mixture; and   adding water to the halogen-containing acid/hydrogen peroxide mixture to provide a solution of the halogen-containing acid, hydrogen peroxide, and water, wherein the water is present in an amount of greater than 90% by volume of the total solution.   
     
     
         11 . The method of  claim 10  wherein said mixing comprises adding said halogen-containing acid to said hydrogen peroxide. 
     
     
         12 . The method of  claim 10  wherein said mixing comprises adding said hydrogen peroxide to said halogen-containing acid. 
     
     
         13 . The method of  claim 10  wherein said halogen-containing acid comprises hydrofluoric (HF) acid, hydrochloric (HCl) acid, hydrobromic (HBr) acid, hydriodic (HI) acid, or any mixtures thereof 
     
     
         14 . The method of  claim 10  wherein said halogen-containing acid is hydrofluoric (HF) acid. 
     
     
         15 . The method of  claim 10  wherein said amount of water in said solution is greater than 98% by volume of the total solution. 
     
     
         16 . The method of  claim 10  wherein said halogen-containing acid and said hydrogen peroxide are mixed in a ratio from 1:1 to 1:20. 
     
     
         17 . A method of etching Ge or a Ge-rich SiGe alloy in a controlled manner, said method comprising contacting a surface of Ge or a Ge-rich SGe alloy with a chemical etchant, said chemical etchant comprising a mixture of a halogen-containing acid, hydrogen peroxide, and water, wherein the water is present in an amount of greater than 90% by volume of the total mixture. 
     
     
         18 . The method of  claim 17  further comprising forming at least one damaged region within said Ge or Ge-rich SiGe alloy prior to said contacting, and wherein said contacting removes portions of said Ge or Ge-rich SiGe alloy that are undamaged relative to said at least one damaged region. 
     
     
         19 . The method of  claim 17  wherein said contacting is performed at a temperature from 5° C. to 60° C. 
     
     
         20 . The method of  claim 17  further comprising providing said chemical etchant prior to said contacting, wherein said providing the chemical etchant comprises mixing, in any order, the halogen-containing acid and the hydrogen peroxide to provide a halogen-containing acid/hydrogen peroxide mixture, and adding water to the halogen-containing acid/hydrogen peroxide mixture.