Selective growth of seed layer for magneto-resistive random access memory

Abstract

A method of fabricating a magneto-resistive random access memory (MRAM) cell with at least one magnetic tunnel junction (MTJ) is provided. The method includes disposing a metallic landing pad within a dielectric pad in a substrate and selectively depositing seed layer material over the substrate. This selective deposition forms a seed layer on which the MTJ is disposable on the metallic landing pad but not the dielectric pad.

What is claimed is: 
     
         1 . An intermediate structure of a mid-fabrication magneto-resistive random access memory (MRAM) cell to be provided with at least one magnetic tunnel junction (MTJ), the intermediate structure comprising:
 a metallic landing pad disposed within a dielectric pad in a substrate; and   a seed layer, which is formed from selective deposition of seed layer material over the substrate, on the metallic landing pad but not the dielectric pad and on which the MTJ is disposable.   
     
     
         2 . The intermediate structure according to  claim 1 , wherein the metallic landing pad comprises at least one or more of copper (Cu), aluminum (Al), tantalum (Ta), tantalum nitride (TaN), titanium (Ti) and titanium nitride (TiN). 
     
     
         3 . The intermediate structure according to  claim 1 , wherein:
 the seed layer has a substantially similar width as the metallic landing pad, and   sidewalls of the seed layer and the metallic landing pad are substantially coplanar.   
     
     
         4 . The intermediate structure according to  claim 1 , wherein the seed layer material comprises metallic material substantially absent copper (Cu). 
     
     
         5 . A magneto-resistive random access memory (MRAM) cell, comprising:
 a metallic landing pad disposed within a dielectric pad in a substrate;   a seed layer, which is formed from selective deposition of seed layer material over the substrate, and which is disposed on the metallic landing pad but not the dielectric pad; and   a magnetic tunnel junction (MTJ) which is deposited and patterned on the seed layer.   
     
     
         6 . The MRAM cell according to  claim 5 , wherein the metallic landing pad comprises at least one or more of copper (Cu), aluminum (Al), tantalum (Ta), tantalum nitride (TaN), titanium (Ti) and titanium nitride (TiN). 
     
     
         7 . The MRAM cell according to  claim 5 , wherein:
 the seed layer has a substantially similar width as the metallic landing pad, and   sidewalls of the seed layer and the metallic landing pad are substantially coplanar.   
     
     
         8 . The MRAM cell according to  claim 7 , wherein the seed layer and the metallic landing pad are annular. 
     
     
         9 . The MRAM cell according to  claim 5 , wherein the seed layer material comprises metallic material substantially absent copper (Cu). 
     
     
         10 . The MRAM cell according to  claim 5 , wherein the MTJ is narrower than the seed layer. 
     
     
         11 . The MRAM cell according to  claim 5 , wherein the MTJ comprises:
 a reference layer disposed on the seed layer;   a free layer remote from the seed layer; and   an insulator interposed between the reference and free layers.   
     
     
         12 . The MRAM cell according to  claim 5 , wherein:
 multiple metallic landing pads are respectively disposed within corresponding ones of multiple dielectric pads in a substrate;   multiple seed layers are respectively formed from selective deposition of seed layer material over the substrate and are respectively disposed on the multiple metallic landing pads but not the dielectric pads; and   multiple MTJs are respectively deposited and patterned on the multiple seed layers.   
     
     
         13 . A magneto-resistive random access memory (MRAM) cell with at least one magnetic tunnel junction (MTJ), the MRAM cell comprising:
 a metallic landing pad within a dielectric pad in a substrate; and   a seed layer deposited over the substrate on which the MTJ is disposable on the metallic landing pad but not the dielectric pad,   wherein:   uppermost and lowermost surfaces of the metallic landing pad are coplanar with uppermost and lowermost surfaces of the dielectric pad, respectively,   the metallic landing pad has a uniform width from the uppermost surface of the dielectric pad to the lowermost surface of the dielectric pad,   the seed layer has a substantially similar width as the uniform width of the metallic landing pad, and   sidewalls of the seed layer and entire sidewalls of the metallic landing pad are substantially coplanar.   
     
     
         14 . The MRAM cell according to  claim 13 , wherein no seed layer material is deposited onto an upper surface of the dielectric pad.