Write line design in MRAM

Abstract

A magnetic random access memory device (MRAM) and the method for forming the same are disclosed. The MRAM has a magnetic tunnel junction (MTJ) device, a first write line, and a second write line orthogonal to the first write line, wherein at least one of the first and second write lines has a width narrower than that of the MTJ.

1 . A method for forming a write line in a magnetic random access memory device, the method comprising: 
 forming a trench in a substrate material;    filling the trench with a conductive filler material;    planarizing the filler material and exposing the substrate material;    forming a conducting buffer layer over the conductive filler material, wherein the buffer layer has a substantially flat surface overlying the conductive filler material; and    forming a magnetic tunnel junction (MTJ) device in contact with the buffer layer, wherein the MTJ has a width of about two times a width of the trench.    
   
   
       2 . The method of  claim 1 , wherein the substrate material is a dielectric material.  
   
   
       3 . The method of  claim 1 , wherein the step of forming a conducting buffer layer further comprises performing a chemical mechanical polish to form a flat contact surface for contacting the MTJ.  
   
   
       4 . The method of  claim 3 , further comprising forming a magnetic layer surrounding the conductive filler material.  
   
   
       5 . The method of  claim 4 , further comprising forming an adhesion layer between the filler material and the magnetic layer.  
   
   
       6 . The method of  claim 4 , wherein the magnetic layer contains Mn.  
   
   
       7 . The method of  claim 4 , wherein the magnetic layer comprises a ferromagnetic material.  
   
   
       8 . The method of  claim 7 , wherein the magnetic layer further comprises an antiferromagnetic layer adjacent to the ferromagnetic material.  
   
   
       9 . A method for forming a write line in a magnetic random access memory device, the method comprising: 
 forming a trench in a substrate material;    filling the trench with a conductive filler material;    planarizing the filler material and exposing the substrate material;    forming a conductive buffer layer over the conductive filler material;    planarizing the buffer layer; and    forming a magnetic tunnel junction (MTJ) device in contact with the buffer layer.    
   
   
       10 . The method of  claim 9 , wherein the MTJ has a width about two times a width of the trench.  
   
   
       11 . The method of  claim 9 , further comprising forming a magnetic layer surrounding the conducting filler material.  
   
   
       12 . The method of  claim 11 , further comprising forming an adhesion layer between the filler material and the magnetic layer.  
   
   
       13 . The method of  claim 11 , wherein the magnetic layer contains Mn.  
   
   
       14 . The method of  claim 11  wherein the magnetic layer comprises a ferromagnetic material.  
   
   
       15 . The method of  claim 14  wherein the magnetic layer further comprises an antiferromagnetic layer adjacent to the ferromagnetic material.  
   
   
       16 . A method for forming a write line in a magnetic random access memory device, the method comprising: 
 forming a trench in a substrate material;    forming a magnetic layer overlying the trench and substantially along the trench sidewalls;    filling the trench with a conductive filler material overlying the magnetic layer;    planarizing the filler material and exposing the substrate material;    forming a conducting buffer layer over the conducting filler material, wherein the buffer layer has a substantially flat surface overlying the conducting filler material; and    forming a magnetic tunnel junction (MTJ) device in contact with the buffer layer.    
   
   
       17 . The method of  claim 16  wherein the MTJ has a width about two times a width of the trench.  
   
   
       18 . The method of  claim 16  wherein the magnetic layer comprises a ferromagnetic material.  
   
   
       19 . The method of  claim 18  wherein the magnetic layer further comprises an antiferromagnetic layer adjacent to the ferromagnetic material.