CPP device with a plurality of metal oxide templates in a confining current path (CCP) spacer

Abstract

A novel CCP scheme is disclosed for a CPP-GMR sensor in which an amorphous metal/alloy layer such as Hf is inserted between a lower Cu spacer and an oxidizable layer such as Al, Mg, or AlCu prior to performing a pre-ion treatment (PIT) and ion assisted oxidation (IAO) to transform the amorphous layer into a first metal oxide template and the oxidizable layer into a second metal oxide template both having Cu metal paths therein. The amorphous layer promotes smoothness and smaller grain size in the oxidizable layer to minimize variations in the metal paths and thereby improves dR/R, R, and dR uniformity by 50% or more. An amorphous Hf layer may be used without an oxidizable layer, or a thin Cu layer may be inserted in the CCP scheme to form a Hf/PIT/IAO or Hf/Cu/Al/PIT/IAO configuration. A double PIT/IAO process may be used as in Hf/PIT/IAO/Al/PIT/IAO or Hf/PIT/IAO/Hf/PIT/IAO schemes.

1 . A method of forming a confining current path (CCP) spacer in a magnetic sensor structure, comprising:
 (a) forming a first copper layer on a ferromagnetic layer;   (b) forming an amorphous layer made of metal, alloy, or metal oxide on said first Cu layer;   (c) depositing an oxidizable layer on said amorphous layer;   (d) performing a pre-ion treatment (PIT) followed by an ion-assisted oxidation (IAO) to transform at least a portion of the first copper layer and the amorphous layer into a first metal oxide template having segregated Cu metal paths therein, and to transform a portion of the first copper layer and the oxidizable layer into a second metal oxide template having segregated Cu metal paths formed therein; and   (e) depositing a second Cu layer on the second metal oxide template.   
     
     
         2 . The method of  claim 1  wherein the amorphous layer is made of Hf, Zr, CoFeB, Ta, Nb, Ti, or B and has a thickness between about 1 and 15 Angstroms, and the oxidizable layer is comprised of Al, AlCu, Mg, MgCu, Ti, Cr, Zr, Ta, Hf, or Fe and has a thickness between about 1 and 15 Angstroms. 
     
     
         3 . The method of  claim 1  further comprised of forming a thin Cu layer having a thickness between 0 and about 6 Angstroms on the amorphous layer before depositing the oxidizable layer. 
     
     
         4 . The method of  claim 1  wherein the first Cu layer is from 0 to about 10 Angstroms thick and the second Cu layer is from 0 to about 10 Angstroms thick. 
     
     
         5 . The method of  claim 1  wherein the PIT process is comprised of a RF power between about 5 and 200 Watts, and an Ar flow rate of about 10 to 200 sccm for a period of about 5 to 200 seconds, and the IAO process is comprised of a RF power between about 5 and 200 Watts, an oxygen flow rate of about 0.01 to 100 sccm, and an Ar flow rate of about 5 to 200 sccm for a period of about 5 to 2000 seconds. 
     
     
         6 . A method of forming a confining current path (CCP) spacer in a magnetic sensor structure, comprising:
 (a) forming a first copper layer on a ferromagnetic layer;   (b) forming an amorphous layer made of metal, alloy, or metal oxide on said first Cu layer;   (c) performing a first PIT process followed by a first IAO process to transform at least a portion of the first copper layer and the amorphous layer into a first metal oxide template having segregated Cu metal paths therein;   (d) depositing an oxidizable layer on said first metal oxide template;   (e) performing a second PIT process followed by a second IAO process to transform the oxidizable layer into a second metal oxide template having segregated Cu metal paths formed therein; and   (f) depositing a second Cu layer on the second metal oxide template.   
     
     
         7 . A method of forming a confining current path (CCP) spacer in a magnetic sensor structure, comprising:
 (a) forming a first copper layer on a ferromagnetic layer;   (b) forming a first amorphous layer made of metal, alloy, or metal oxide on said first Cu layer;   (c) performing a first PIT process followed by a first IAO process to transform at least a portion of the first copper layer and the first amorphous layer into a first metal oxide template having segregated Cu metal paths therein;   (d) depositing an oxidizable layer on said first metal oxide template;   (e) depositing a second amorphous layer on said oxidizable layer;   (f) performing a second PIT process followed by a second IAO process to transform the oxidizable layer into a second metal oxide template having segregated Cu metal paths formed therein and to transform the second amorphous layer into a third metal oxide template having segregated metal paths formed therein; and   (g) depositing a second Cu layer on the third metal oxide template.   
     
     
         8 . A method of forming a confining current path (CCP) spacer in a magnetic sensor structure, comprising:
 (a) forming a first copper layer on a ferromagnetic layer;   (b) forming an amorphous layer made of a metal, alloy, or metal oxide on said first Cu layer;   (c) performing a PIT process followed by an IAO process to transform at least a portion of the first copper layer and amorphous layer into a first metal oxide template with segregated Cu metal paths formed therein; and   (d) depositing a second Cu layer on the first metal oxide template.   
     
     
         9 . The method of  claim 8  wherein the amorphous layer is made of Hf, Zr, CoFeB, Ta, Nb, Ti, or B and has a thickness between about 1 and 15 Angstroms, or the amorphous metal oxide has a thickness less than about 15 Angstroms. 
     
     
         10 . The method of  claim 8  wherein the first Cu layer is from 0 to about 10 Angstroms thick and the second Cu layer is from 0 to about 10 Angstroms thick. 
     
     
         11 . A method of forming a confining current path (CCP) spacer in a magnetic sensor structure, comprising:
 (a) forming a first copper layer on a ferromagnetic layer;   (b) forming a first amorphous layer made of a metal, alloy, or metal oxide on said first Cu layer;   (c) forming a thin copper layer on the first amorphous layer;   (d) forming a second amorphous layer on the thin copper layer; and   (e) performing a PIT process followed by an IAO process to transform the first amorphous layer into a first metal oxide template with segregated Cu metal paths formed therein and to transform the second amorphous layer into a second metal oxide template with segregated Cu metal paths therein.   (d) depositing a second Cu layer on the first metal oxide template.   
     
     
         12 . The method of  claim 11  wherein said thin Cu layer has a thickness between 0 and about 6 Angstroms. 
     
     
         13 . The method of  claim 11  wherein the first metal oxide template is comprised of a different metal than in the second metal oxide template. 
     
     
         14 . The method of  claim 11 , wherein the first metal oxide template is comprised of the same metal as in the second metal oxide template. 
     
     
         15 . A method of forming a confining current path (CCP) spacer in a magnetic sensor structure, comprising:
 (a) forming a first copper layer on a ferromagnetic layer;   (b) forming a first amorphous layer made of a metal, alloy, or metal oxide on said first Cu layer;   (c) performing a first PIT process followed by a first IAO process to transform said first amorphous layer into a first metal oxide template having copper metal paths formed therein;   (d) forming a second amorphous layer on the first metal oxide template; and   (e) performing a second PIT process followed by a second IAO process to transform the second amorphous layer into a second metal oxide template with segregated Cu metal paths formed therein.   
     
     
         16 . A method of forming a confining current path (CCP) spacer in a magnetic sensor structure, comprising:
 (a) forming a first copper layer on a ferromagnetic layer;   (b) forming an oxidizable layer on said first Cu layer;   (c) forming an amorphous layer made of metal, alloy, or metal oxide on said oxidizable layer; and   (d) performing a PIT process followed by an IAO process to transform the oxidizable layer into a first metal oxide template having segregated Cu metal paths therein and to transform the amorphous layer into a second metal oxide template having segregated Cu metal paths formed therein.