Conductive oxide film, display device, and method for forming conductive oxide film

Abstract

One embodiment of the present invention provides a conductive oxide film having high conductivity and high transmittance of visible light. The conductive oxide film having high conductivity and high transmittance of visible light can be obtained by forming a conductive oxide film at a high substrate temperature in the film formation and subjecting the conductive oxide film to nitrogen annealing treatment. The conductive oxide film has a crystal structure in which c-axes are aligned in a direction perpendicular to a surface of the film.

What is claimed is: 
     
         1 . A method for forming a conductive oxide film comprising the steps of:
 forming a conductive oxide film over a substrate by a sputtering method at a substrate temperature of 200° C. or higher; and   performing nitrogen annealing treatment on the conductive oxide film.   
     
     
         2 . The method for forming a conductive oxide film according to  claim 1 , wherein the step of forming the conductive oxide film is performed in an atmosphere including an argon gas. 
     
     
         3 . The method for forming a conductive oxide film according to  claim 2 , wherein a percentage of the argon gas is more than or equal to 70%. 
     
     
         4 . The method for forming a conductive oxide film according to  claim 1 , wherein a temperature in the nitrogen annealing treatment is higher than or equal to 350° C.