Copper-alloy barrier layers for metallization in thin-film transistors and flat panel displays

Abstract

In various embodiments, electronic devices such as thin-film transistors incorporate electrodes featuring a conductor layer and, disposed below the conductor layer, a barrier layer comprising an alloy of Cu and one or more refractory metal elements selected from the group consisting of Ta, Nb, Mo, W, Zr, Hf, Re, Os, Ru, Rh, Ti, V, Cr, and Ni.

What is claimed is: 
     
         1 .- 38 . (canceled) 
     
     
         39 . A thin-film transistor comprising:
 a substrate comprising at least one of silicon or glass; and   an electrode comprising:
 (i) disposed on the substrate, a barrier layer consisting essentially of at least one metal, the at least one metal comprising an alloy of Cu and one or more refractory metal elements selected from the list consisting of Ta, Nb, Mo, W, Zr, Hf, Re, Os, Ru, Rh, Ti, V, Cr, and Ni, and 
 (ii) disposed on the barrier layer, a conductor layer comprising at least one of Cu, Ag, Al, or Au. 
   
     
     
         40 . The thin-film transistor of  claim 39 , wherein the substrate comprises glass. 
     
     
         41 . The thin-film transistor of  claim 39 , wherein the substrate comprises silicon. 
     
     
         42 . The thin-film transistor of  claim 41 , wherein the substrate comprises amorphous silicon. 
     
     
         43 . The thin-film transistor of  claim 39 , wherein the at least one metal of the barrier layer comprises an alloy of Cu, Ta, and Cr. 
     
     
         44 . The thin-film transistor of  claim 43 , wherein the barrier layer consists essentially of 1 weight %-12 weight % Ta, 1 weight %-5 weight % Cr, and the balance Cu. 
     
     
         45 . The thin-film transistor of  claim 43 , wherein the barrier layer consists essentially of approximately 5 weight % Ta, approximately 2 weight % Cr, and the balance Cu. 
     
     
         46 . The thin-film transistor of  claim 43 , wherein the barrier layer consists essentially of approximately 2 weight % Ta, approximately 1 weight % Cr, and the balance Cu. 
     
     
         47 . The thin-film transistor of  claim 39 , wherein the at least one metal of the barrier layer comprises an alloy of Cu, Ta, and Ti. 
     
     
         48 . The thin-film transistor of  claim 47 , wherein the barrier layer consists essentially of 1 weight %-12 weight % Ta, 1 weight %-5 weight % Ti, and the balance Cu. 
     
     
         49 . The thin-film transistor of  claim 47 , wherein the barrier layer consists essentially of approximately 5 weight % Ta, approximately 2 weight % Ti, and the balance Cu. 
     
     
         50 . The thin-film transistor of  claim 39 , wherein the at least one metal of the barrier layer comprises an alloy of Cu, Nb, and Cr. 
     
     
         51 . The thin-film transistor of  claim 50 , wherein the barrier layer consists essentially of 1 weight %-10 weight % Nb, 1 weight %-5 weight % Cr, and the balance Cu. 
     
     
         52 . The thin-film transistor of  claim 50 , wherein the barrier layer consists essentially of approximately 5 weight % Nb, approximately 2 weight % Cr, and the balance Cu. 
     
     
         53 . The thin-film transistor of  claim 39 , wherein (i) the electrode comprises a sidewall comprising (a) an exposed portion of the barrier layer, (b) an exposed portion of the conductor layer, and (c) an interface between the exposed portion of the barrier layer and the exposed portion of the conductor layer, and (ii) the sidewall of the electrode is substantially free of discontinuities notwithstanding the interface. 
     
     
         54 . The thin-film transistor of  claim 39 , wherein the substrate is substantially free of Cu diffusion from the barrier layer. 
     
     
         55 . The thin-film transistor of  claim 39 , wherein (i) the barrier layer comprises a plurality of crystalline grains separated by grain boundaries, (ii) at least one of the grain boundaries comprises a particulate therein, and (iii) the particulate comprises a reaction product of silicon and at least one of the refractory metal elements. 
     
     
         56 . The thin-film transistor of  claim 39 , wherein:
 the barrier layer comprises a plurality of crystalline grains separated by grain boundaries; and   a concentration of the one or more refractory metal elements within the grain boundaries is larger than a concentration of the one or more refractory metal elements within the crystalline grains.