Magnetoresistive memory device and method of manufacturing magnetoresistive memory device

Abstract

According to an embodiment, a magnetoresistive memory device includes a layer stack. The layer stack includes a first ferromagnet, an insulator on the first ferromagnet, and a second ferromagnet on the insulator. A nonmagnet is provided above the layer stack. A first conductor is provided on the nonmagnet. A hard mask is provided above the first conductor. The nonmagnet includes a material that is removed at a first etching rate against a first ion beam. The first conductor includes a material that is removed at a second etching rate against the first ion beam. The first etching rate is lower than the second etching rate.

What is claimed is: 
     
         1 . A magnetoresistive memory device comprising:
 a layer stack including a first ferromagnet, an insulator on the first ferromagnet, and a second ferromagnet on the insulator;   a nonmagnet above the layer stack;   a first conductor on the nonmagnet; and   a hard mask above the first conductor, wherein   the nonmagnet comprises a material that is removed at a first etching rate against a first ion beam,   the first conductor comprises a material that is removed at a second etching rate against the first ion beam, and   the first etching rate is lower than the second etching rate.   
     
     
         2 . The device according to  claim 1 , wherein:
 a side face of the nonmagnet consists with a face different from an extended face of a side face of the layer stack.   
     
     
         3 . The device according to  claim 2 , wherein:
 a side face of the first conductor consists a face different from an extended face of a side face of the nonmagnet.   
     
     
         4 . The device according to  claim 2 , wherein:
 the nonmagnet comprises one of tantalum, tungsten, hafnium, iron, cobalt, aluminum, and molybdenum.   
     
     
         5 . The device according to  claim 4 , wherein:
 the first conductor comprises one of platinum, tungsten, tantalum, and ruthenium.   
     
     
         6 . The device according to  claim 2 , wherein:
 the nonmagnet comprises one boride of tantalum, tungsten, hafnium, iron, cobalt, aluminum, and molybdenum.   
     
     
         7 . The device according to  claim 6 , wherein:
 the first conductor comprises one of platinum, tungsten, tantalum, and ruthenium.   
     
     
         8 . The device according to  claim 1 , wherein:
 the nonmagnet comprises one of tantalum, tungsten, hafnium, iron, cobalt, aluminum, and molybdenum.   
     
     
         9 . The device according to  claim 5 , wherein:
 the first conductor comprises one of platinum, tungsten, tantalum, and ruthenium.   
     
     
         10 . The device according to  claim 1 , wherein:
 the nonmagnet comprises one boride of tantalum, tungsten, hafnium, iron, cobalt, aluminum, and molybdenum.   
     
     
         11 . The device according to  claim 10 , wherein:
 the first conductor comprises one of platinum, tungsten, tantalum, and ruthenium.  10     
     
     
         12 . A method of manufacturing a magnetoresistive memory device, the method comprising:
 forming a first layer stack above a substrate, the first layer stack comprising a first ferromagnet, an insulator above the first ferromagnet, a second ferromagnet above the insulator, a nonmagnet above the second ferromagnet, and a first conductor above the nonmagnet;   forming a hard mask having an opening on the first layer stack;   irradiating, through the opening, the first layer stack with a first ion beam traveling at a first angle with respect to a normal to the substrate, the nonmagnet being etched at a first etching rate by the first ion beam, the first conductor being etched at a second etching rate by the first ion beam, and the first etching rate being lower than the second etching rate; and   irradiating, through the opening, the first layer stack with a second ion beam traveling at a second angle with respect to the normal to the substrate, the second angle being smaller than the first angle.   
     
     
         13 . The method according to  claim 12 , wherein:
 the nonmagnet comprises one of tantalum, tungsten, hafnium, iron, cobalt, aluminum, and molybdenum.   
     
     
         14 . The method according to  claim 13 , wherein:
 the first conductor comprises one of platinum, tungsten, tantalum, and ruthenium.   
     
     
         15 . The method according to  claim 12 , wherein:
 the nonmagnet comprises one boride of tantalum, tungsten, hafnium, iron, cobalt, aluminum, and molybdenum.   
     
     
         16 . The method according to  claim 13 , wherein:
 the first conductor comprises one of platinum, tungsten, tantalum, and ruthenium.