Selenium containing electrodeposition solution and methods

Abstract

The present inventions relate to selenium containing electrodeposition solutions used to manufacture solar cell absorber layers. In one aspect is described an electrodeposition solution to electrodeposit a Group IB-Group VIA thin film that includes a a solvent; a Group IB material source; a Group VIA material source; and at least one complexing that forms a complex ion of the Group IB material. Also described are methods of electroplating using electrodeposition solutions.

1 . An electrodeposition solution to electrodeposit a Group IB-Group VIA thin film, comprising:
 a solvent;   a Group IB material source that dissolves in the solvent and provides a Group IB material;   a Group VIA material source that dissolves in the solvent and provides a Group VIA material; and   at least one complexing that forms a complex ion of the Group IB material wherein such complex ion dissolves in the solvent;   an adhesion promoting agent;   a corrosion inhibitor; and   wherein the pH of the electrodeposition solution is in the range of 1-13.   
     
     
         2 . The electrodeposition solution of  claim 1 , wherein the Group IB material source comprises a copper source and the Group VIA material comprises a selenium source. 
     
     
         3 . The electrodeposition solution of  claim 2 , wherein the copper source of copper ions comprises at least one of dissolved copper metals and dissolved copper salts, wherein the copper salts include copper-chloride, copper-sulfate, copper-acetate, copper-oxide, copper-hydroxide, copper-nitrate, copper-phosphate, copper-tetraflouroborate, copper-citrate, copper-gluconate, copper-sulfamate, and copper-carbonate. 
     
     
         4 . The solution of  claim 1 , wherein the Group Se material source comprises at least one of dissolved elemental Se, acids of Se, and dissolved Se compounds, wherein the Se compounds include oxides, chlorides, sulfates, nitrates, perchlorides and phosphates of Se. 
     
     
         5 . The solution of  claim 4  wherein the complexing agent includes at least one of a carboxylate functional group and an amine functional group. 
     
     
         6 . The solution of  claim 5  wherein the complexing agent comprises one of an acid and an alkali metal salt of the acid and an ammonium salt of the acid, and wherein the acid comprises one of tartaric acid, citric acid, acetic acid, malonic acid, malic acid, succinic acid, ethylenediamine (EN), ethylenediamine tetraacetic acid (EDTA), nitrilotriacetic acid (NTA), and hydroxyethylethylenediaminetriacetic acid (HEDTA). 
     
     
         7 . The solution of  claim 6  wherein the complexing agent comprises an alkali metal salt of the acid is selected from the group of sodium and potassium salts tartaric acid, citric acid, acetic acid, malonic acid, malic acid, succinic acid, ethylenediamine (EN), ethylenediamine tetraacetic acid (EDTA), nitrilotriacetic acid (NTA), and hydroxyethylethylenediaminetriacetic acid (HEDTA). 
     
     
         8 . The solution of  claim 6  wherein the complexing agent comprises an ammonium salt of the acid is selected from the group of ammonium salts of tartaric acid, citric acid, acetic acid, malonic acid, malic acid, succinic acid, ethylenediamine (EN), ethylenediamine tetraacetic acid (EDTA), nitrilotriacetic acid (NTA), and hydroxyethylethylenediaminetriacetic acid (HEDTA). 
     
     
         9 . The electrodeposition solution of  claim 4 , wherein the amount of the complexing agent is in the range of 5 mM/L to 0.55 M/L. 
     
     
         10 . The electrodeposition solution of  claim 1 , wherein the adhesion promoting agent comprises organic compounds with at least one amine functional group and at least one aminopropyl group. 
     
     
         11 . The electrodeposition solution of  claim 11 , wherein the adhesion promoting agent comprises at least one of 1,4-Bis(3-aminopropyl) piperazine and N,N′ Bis(3-aminopropyl) ethylenediamine and any possible mixture of these. 
     
     
         12 . The electrodeposition solution of  claim 7 , wherein the amount of the adhesion promoting agent is in the range of 1.0 mM/L to 40 mM/L. 
     
     
         13 . The electrodeposition solution of  claim 1 , wherein the corrosion inhibitor comprises a multihydric alcohol. 
     
     
         14 . The electrodeposition solution of  claim 13 , wherein the corrosion inhibitor is glycerol. 
     
     
         15 . The electrodeposition solution of  claim 13 , wherein the amount of the corrosion inhibitor is in the range of 20 mM/L to 500 mM/L. 
     
     
         16 . The electrodeposition solution of  claim 1  further comprising a grain refiner including one of chloride, pyrophosphate and sulfite. 
     
     
         17 . The electrodeposition solution of  claim 1  further comprising a conductivity improving agent including ammonium sulfate. 
     
     
         18 . The electrodeposition solution of  claim 1 , wherein the amount of the conductivity improving agent is in the range of 5 mM/L to 0.55 M/L. 
     
     
         19 . A method of electrodepositing an adherent film comprising copper selenide alloy material on a conductive layer, comprising:
 providing an electrodeposition solution comprising a solvent, a copper ion source, a selenium ion source, at least one complexing agent and at least one adhesion promoting agent, the adhesion promoting agent suppressing the formation of colloidal particles on the substrate and in the plating solution, wherein the electrodeposition solution has a pH value in the range of 1-13;   contacting the electrodeposition solution with the surface of the conductive layer and an anode;   establishing a potential difference between the anode and the conductive layer; and   electrodepositing the copper selenide film on the surface of the conductive layer.   
     
     
         20 . The method of  claim 19 , wherein the conductive layer is one of indium, gallium, selenium copper and their alloys. 
     
     
         21 . The method of  claim 19  wherein the copper ion source is copper sulfate pentahydrate, and the selenium ion source is selenium oxide. 
     
     
         22 . The method of  claim 19 , wherein said adhesion promoting agent comprises organic compounds with at least one amine functional group and at least one aminopropyl group. 
     
     
         23 . The method of  claim 19 , wherein the step of electrodepositing includes varying electrodeposition current density during the electrodeposition. 
     
     
         24 . The method of  claim 19 , wherein the step of electrodepositing includes pulsing the current density between a high and a low current density for desirable time intervals to electrodeposit laminated selenide films containing different copper concentrations. 
     
     
         25 . The method of  claim 19  wherein said copper selenide film has a graded copper composition within the film thickness. 
     
     
         26 . The method of  claim 19  wherein the step of electrodepositing is performed using one of galvanostatic electrodeposition, potentiostatic electrodeposition , and various combinations of current and voltage mode. 
     
     
         27 . A method of electrodepositing a precursor on a conductive layer, comprising:
 electrodepositing a copper selenide film on the conductive layer using an electrodeposition solution, the electrodeposition solution comprising a copper ion source, a selenium ion source, at least one complexing agent, at least one adhesion promoting agent;   depositing a thin film including a Group IB material, at least one Group IIIA material onto the copper selenide film, wherein the step of depositing uses a physical vapor deposition technique.   
     
     
         28 . The method of  claim 27  wherein the thin film further includes a sodium salt. 
     
     
         29 . The method of  claim 27  wherein the Group IB material includes copper, and the Group IIIA material includes gallium and indium.