Synthesis of high-purity bulk copper indium gallium selenide materials

Abstract

A method for forming a high purity, copper indium gallium selenide (CIGS) sputtering target is disclosed. The method includes sealing precursor materials for forming the bulk material in a reaction vessel. The precursor materials include copper, at least one chalcogen selected from selenium, sulfur, and tellurium, and at least one element from group IIIA of the periodic table, which may be selected from gallium, indium, and aluminum. The sealed reaction vessel is heated to a temperature at which the precursor materials react to form the bulk material. The bulk material is cooled in the vessel to a temperature below the solidification temperature of the bulk material and opened to release the formed bulk material. A sputtering target formed by the method can have an oxygen content of 10 ppm by weight, or less.

1 . A sputtering target formed by the method comprising:
 sealing precursor materials for forming a bulk polycrystalline material in a reaction vessel, the precursor materials comprising copper, at least one chalcogen selected from selenium, sulfur, and tellurium, and at least one element selected from gallium, indium, and aluminum;   heating the sealed reaction vessel to a temperature at which the precursor materials react to form the bulk material, wherein the heating is to a maximum temperature of 776° C., wherein the heating includes:
 ramping the temperature of the sealed vessel to a first soak temperature; 
 maintaining the first soak temperature for a sufficient time for at least some chalcogen in at least one of liquid and vapor form to react with other precursor materials; 
 ramping the temperature from the first soak temperature to a second soak temperature; and 
 maintaining the second soak temperature for sufficient time to form the bulk material; and 
   at a temperature at which the bulk material is solid, opening the reaction vessel and removing the formed bulk material.   
     
     
         2 . A sputtering target comprising bulk CIGS material and having an oxygen content of less than 10 ppm by weight. 
     
     
         3 . The sputtering target of  claim 2 , wherein the target comprises chalcogen at greater than a stoichiometric amount of the CIGS material. 
     
     
         4 . The sputtering target of  claim 3 , wherein the chalcogen is at least 110% of the stoichiometric amount. 
     
     
         5 . The sputtering target of  claim 2 , wherein the target has a width of at least 0.5 cm. 
     
     
         6 . The sputtering target of  claim 2 , wherein the target has a weight of at least 10 grams.