Selenium electroplating chemistries and methods

Abstract

An electroplating solution to electroplate a selenium containing film on a conductive surface is provided. The electroplating solution includes a solvent, a selenium source material that dissolves in the solvent; an anti-coagulation agent that inhibits Se particle growth and promotes Se particle dispersal. The pH value of the electroplating solution is in the range of 2-10.

1 . A solution to electroplate a selenium containing film on a conductive surface, comprising:
 a solvent,   a selenium source material that dissolves in the solvent, and   an anti-coagulation agent that inhibits growth of Se particles and promotes the dispersal of such Se particles when electroplating a selenium containing film onto a conductive surface; wherein the pH value of the solution is in the range of 2-10.   
     
     
         2 . The solution of  claim 1 , wherein the solution includes substantially no reducing agents. 
     
     
         3 . The solution of  claim 2  wherein the pH of the solution is in the range of 4-8. 
     
     
         4 . The solution of  claim 2 , wherein the solvent comprises water. 
     
     
         5 . The solution of  claim 4 , wherein the selenium source material comprises at least one of selenious acid, selenium oxide, and a metal selenide group material, wherein the metal selenide group material comprises a selenide selected from the group consisting of potassium selenide, sodium selenide, calcium selenide, copper selenide, indium selenide, and gallium selenide 
     
     
         6 . The solution of  claim 1 , wherein the anti-coagulation agent comprises a sulfonate based material. 
     
     
         7 . The solution of  claim 5 , wherein the anti-coagulation agent comprises a sulfonate based material. 
     
     
         8 . The solution of  claim 7 , wherein the sulfonate based material comprises one of lignosulfonate, sodium lignosulfonate, potassium lignosulfonate, calcium lignosulfonate, ammonium lignosulfonate and lignin sulfonic acids. 
     
     
         9 . The solution of  claim 6 , wherein the sulfonate based material has a concentration in the range of 2 parts per million to 500 parts per million. 
     
     
         10 . The solution of  claim 9  wherein the sulfonate based material has a concentration in the range of 5 parts per million to 125 parts per million. 
     
     
         11 . The solution of  claim 1 , wherein the selenium source comprises Se dissolved in one of sulfuric acid, nitric acid and hydrochloric acid. 
     
     
         12 . The solution of  claim 1  further comprising at least one of indium, gallium and copper ions. 
     
     
         13 . A method of electroplating a film comprising selenium on a surface of a conductive layer, comprising the steps:
 (a) providing an electroplating solution comprising a solvent, a selenium source to supply selenium ions to the solvent, and an additive that inhibits growth of Se particles and promotes the dispersal of such Se particles during the step of electroplating the selenium containing film on the surface of the conductive, wherein the electroplating solution has a pH value in the range of 2 and 10;   (b) contacting the electroplating solution with the surface of the conductive layer and the anode;   (c) establishing a potential difference between the anode and the conductive layer; and   (d) electroplating the Se containing film on the surface of the conductive layer.   
     
     
         14 . The method of  claim 13  wherein the Se containing film is substantially free of aggregated Se particles. 
     
     
         15 . The method of  claim 13  wherein the conductive layer is one of copper, indium and gallium. 
     
     
         16 . The method of  claim 13  wherein the pH value of the electroplating solution is in the range of 4-8. 
     
     
         17 . The method of  claim 13 , wherein the electroplating solution of step (a) comprises substantially no reducing agents. 
     
     
         18 . The method of  claim 13 , wherein the selenium source comprises at least one of selenious acid, selenium oxide, and a metal selenide group material, wherein the metal selenide group material is selected from the group consisting of potassium selenide, sodium selenide, calcium selenide copper selenide, indium selenide, and gallium selenide. 
     
     
         19 . The method of  claim 13 , wherein the additive comprises a sulfonate based material. 
     
     
         20 . The method of  claim 19 , wherein the sulfonate based material comprises at least one of lignosulfonate, sodium lignosulfonate, potassium lignosulfonate, calcium lignosulfonate, ammonium lignosulfonate, a lignin sulfonic acid, and an alkali metal salt of a lignin sulfonic acid. 
     
     
         21 . The method of  claim 19 , wherein the sulfonate based material has a concentration in the range of 2 parts per million to 500 parts per million. 
     
     
         22 . The method of  claim 21 , wherein the sulfonate based material has a concentration in the range of 5 parts per million to 125 parts per million. 
     
     
         23 . The method of  claim 13 , wherein the electroplating solution further comprises at least one of indium ions, gallium ions and copper ions. 
     
     
         24 . The method of  claim 13 , wherein the selenium source comprises Se dissolved in one of sulfuric acid, nitric acid and hydrochloric acid.