Method of manufacturing a magnetic tunnel junction device

Abstract

A method of manufacturing a magnetic tunnel junction device, in which a stack ( 1 ) comprising two magnetic layers ( 3, 7 ) and a barrier layer ( 5 ) extending in between is formed. One of the magnetic layers is structured by means of etching, in which, during etching, a part of this layer is made thinner by removing material until a rest layer ( 7 r ) remains. This rest layer is passivated by chemical conversion. In the relevant method, it is prevented that the magnetic layer which is not to be structured is detrimentally influenced during structuring of the other magnetic layer.

1 . A method of manufacturing a magnetic tunnel junction device, in which a stack comprising two magnetic layers and a barrier layer extending in between is formed, characterized in that one of the magnetic layers is structured by means of etching, in which, during etching, a part of the relevant layer is made thinner by removing material until a rest layer remains, whereafter the electrical resistance of the rest layer is increased by chemical conversion.  
     
     
         2 . A method as claimed in  claim 1 , characterized in that the chemical conversion is effected by oxidation and/or nitridation.  
     
     
         3 . A method as claimed in  claim 1 , characterized in that physical etching is performed.  
     
     
         4 . A method as claimed in  claim 1 , characterized in that the magnetic layer to be structured is built up from, consecutively, a basic layer and a layer structure comprising at least a further layer for magnetic pinning of the basic layer.  
     
     
         5 . A method as claimed in  claim 3 , characterized in that, prior to physical etching, the layer structure is chemically etched until the basic layer is reached.  
     
     
         6 . A method as claimed in  claim 2 , characterized in that an oxidation of the rest layer is effected by thermal oxidation, plasma oxidation or UV-assisted oxidation.  
     
     
         7 . A method as claimed in  claim 2 , characterized in that a nitridation of the rest layer is effected by thermal nitridation or plasma nitridation.  
     
     
         8 . A magnetic tunnel junction device obtained by means of the method as claimed in  claim 1 .  
     
     
         9 . A magnetic tunnel junction device as claimed in  claim 8 , in which the layer other than the structured magnetic layer comprises a soft-magnetic layer which is usable as a flux guide.  
     
     
         10 . A magnetic field sensor provided with the magnetic tunnel junction device as claimed in  claim 8 .  
     
     
         11 . A magnetic field sensor as claimed in  claim 9 , provided with a magnetic yoke which is in magnetic contact with the soft-magnetic layer of the magnetic tunnel junction device.  
     
     
         12 . A magnetic memory provided with the magnetic tunnel junction device as claimed in  claim 8.