Tunneling magnetoresistance transducer and method for manufacturing the same

Abstract

In a tunneling magnetoresistance transducer including first and second ferromagnetic layers and a tunnel barrier layer made of insulating material sandwiched by the first and second ferromagnetic layers, the resistance of the tunnel barrier layer remains essentially constant independent of the temperature of the transducer.

1 . A method for manufacturing a tunnel magnetoresistance transducer, comprising the steps of: 
 growing a first ferromagnetic layer in a sputtering apparatus;    growing a conductive layer on said first ferromagnetic layer in said sputtering apparatus;    introducing oxygen into said sputtering apparatus so as to naturally oxidize said conductive layer, so that a tunnel barrier layer is made of oxide of said conductive layer; and    growing a second ferromagnetic layer on the oxide of said conductive layer.    
     
     
         2 . The method as set forth in  claim 1 , wherein said oxygen introducing step completely oxidizes said conductive layer.  
     
     
         3 . The method as set forth in  claim 1 , wherein said conductive layer is made of one of metal and amphoteric metal.  
     
     
         4 . The method as set forth in  claim 1 , wherein said conductive layer is made of one of Al, Mg and lanthanoid metal.  
     
     
         5 . The method as set forth in  claim 1 , wherein said oxygen introducing step introduces oxygen while irradiating said transducer with ultraviolet rays.  
     
     
         6 . The method as set forth in  claim 1 , wherein said oxygen introducing step introduces oxygen while irradiating said transducer with X-rays.  
     
     
         7 . A method for manufacturing a tunnel magnetoresistance transducer, comprising the steps of: 
 growing a first ferromagnetic layer in a sputtering apparatus;    growing a conductive layer on said first ferromagnetic layer in said sputtering apparatus;    introducing nitrogen into said sputtering apparatus so as to naturally nitriding said conductive layer, so that a tunnel barrier layer is made of nitride of said conductive layer; and    growing a second ferromagnetic layer on the nitride of said conductive layer.    
     
     
         8 . The method as set forth in  claim 7 , wherein said nitrogen introducing step completely nitrides said conductive layer.  
     
     
         9 . The method as set forth in  claim 7 , wherein said conductive layer is made of one of metal and amphoteric metal.  
     
     
         10 . The method as set forth in  claim 7 , wherein said conductive layer is made of one of Al, Mg and lanthanoid metal.  
     
     
         11 . The method as set forth in  claim 7 , wherein said nitrogen introducing step introduces nitrogen while irradiating said transducer with ultraviolet rays.  
     
     
         12 . The method as set forth in  claim 7 , wherein said nitrogen introducing step introduces nitrogen while irradiating said transducer with X-rays.  
     
     
         13 . A method for manufacturing a tunnel magnetoresistance transducer, comprising the steps of: 
 growing a first ferromagnetic layer in a sputtering apparatus;    introducing oxygen into said sputtering apparatus so as to naturally oxidize said first ferromagnetic layer, so that an oxide layer of said first ferromagnetic layer is formed;    growing a conductive layer on the oxide layer of said first ferromagnetic layer in said sputtering apparatus;    introducing oxygen into said sputtering apparatus so as to naturally and completely oxidize said conductive layer while oxygen is diffused from the oxide layer of said first ferromagnetic layer to said conductive layer, so that a tunnel barrier layer is made of oxide of said conductive layer; and    growing a second ferromagnetic layer on the oxide of said conductive layer.    
     
     
         14 . The method as set forth in  claim 13 , wherein said conductive layer is made of one of metal and amphoteric metal.  
     
     
         15 . The method as set forth in  claim 13 , wherein said conductive layer is made of one of Al, Mg and lanthanoid metal.  
     
     
         16 . The method as set forth in  claim 13 , wherein said oxygen introducing step introduces oxygen while irradiating said transducer with ultraviolet rays.  
     
     
         17 . The method as set forth in  claim 13 , wherein said oxygen introducing step introduces oxygen while irradiating said transducer with X-rays.  
     
     
         18 . A method for manufacturing a tunnel magnetoresistance transducer, comprising the steps of: 
 growing a first ferromagnetic layer in a sputtering apparatus;    introducing nitrogen into said sputtering apparatus so as to naturally nitride said fist ferromagnetic layer, so that a nitride layer of said first ferromagnetic layer is formed;    growing a conductive layer on the nitride layer of said first ferromagnetic layer in said sputtering apparatus;    introducing nitrogen into said sputtering apparatus so as to naturally and completely nitride said conductive layer while nitrogen is diffused from the nitride layer of said first ferromagnetic layer to said conductive layer, so that a tunnel barrier layer is made of nitride of said conductive layer; and    growing a second ferromagnetic layer on the nitride of said conductive layer.    
     
     
         19 . The method as set forth in  claim 18 , wherein said conductive layer is made of one of metal and amphoteric metal.  
     
     
         20 . The method as set forth in  claim 18 , wherein said conductive layer is made of one of Al, Mg and lanthanoid metal.  
     
     
         21 . The method as set forth in  claim 18 , wherein said nitrogen introducing step introduces nitrogen while irradiating said transducer with ultraviolet rays.  
     
     
         22 . The method as set forth in  claim 18 , wherein said nitrogen introducing step introduces nitrogen while irradiating said transducer with X-rays.