Systems and methods for forming selective metal electrode layers for resistive switching memories

Abstract

A method for selectively depositing a platinum layer on a substrate includes providing an electroless deposition solution including a platinum precursor and at least one of water and/or a pH balancing solution. A substrate including a patterned metal layer and one or more dielectric layers is immersed in the electroless deposition solution for a first predetermined period. The platinum layer is selectively deposited on the patterned metal layer but not on the one or more dielectric layers. The substrate is removed from the electroless deposition solution after the first predetermined period.

What is claimed is: 
     
         1 . A method for selectively depositing a platinum layer on a substrate, comprising:
 providing an electroless deposition solution including a platinum precursor and at least one of water and/or a pH balancing solution;   immersing a substrate including a patterned metal layer and one or more dielectric layers in the electroless deposition solution for a first predetermined period,   wherein the platinum layer is selectively deposited on the patterned metal layer but not on the one or more dielectric layers; and   removing the substrate from the electroless deposition solution after the first predetermined period.   
     
     
         2 . The method of  claim 1 , further comprising adding a reducing agent to the electroless deposition solution after the substrate is immersed in the electroless deposition solution. 
     
     
         3 . The method of  claim 2 , wherein the reducing agent comprises titanium chloride. 
     
     
         4 . The method of  claim 2 , wherein the reducing agent comprises hydrazine. 
     
     
         5 . The method of  claim 1 , wherein the patterned metal layer includes at least one of cobalt (Co), ruthenium (Ru), tungsten (W), tungsten nitride (WN), and/or titanium nitride (TiN). 
     
     
         6 . The method of  claim 1 , wherein the pH balancing solution includes ammonium hydroxide. 
     
     
         7 . The method of  claim 6 , wherein the pH balancing solution adjusts the pH of the electroless deposition solution to a range between 8 and 11. 
     
     
         8 . The method of  claim 6 , wherein the pH balancing solution adjusts the pH of the electroless deposition solution to a range between 9 and 10. 
     
     
         9 . The method of  claim 1 , further comprising pre-cleaning the substrate to remove an oxide layer on the patterned metal layer prior to depositing the platinum layer. 
     
     
         10 . The method of  claim 1 , further comprising depositing a palladium activation/seed layer prior to depositing the platinum layer. 
     
     
         11 . The method of  claim 1 , wherein the substrate forms part of a resistive random access memory (RRAM). 
     
     
         12 . The method of  claim 1 , further comprising:
 depositing a first layer on the platinum layer; and   depositing a second layer on the first layer.   
     
     
         13 . The method of  claim 12 , wherein the first layer comprises at least one of HfO x , TiO x , TaO x , WO x , Al 2 O 3 , or combinations thereof. 
     
     
         14 . The method of  claim 13 , wherein the at least one of HfO x , TiO x , TaO x , and/or WO x  are stoichiometric. 
     
     
         15 . The method of  claim 13 , wherein the at least one of HfO x , TiO x , TaO x , and/or WO x  are non-stoichiometric. 
     
     
         16 . The method of  claim 12 , wherein the second layer includes titanium nitride (TiN).