Method of forming tunnel magnetoresistance (tmr) elements and tmr sensor element

Abstract

A method includes performing an ion beam etching process on a tunnel magnetoresistance (TMR) stack to remove material portions of a first magnetic layer and a tunnel barrier layer of the TMR stack. The ion beam etching process stops at a top surface of a second magnetic layer of the TMR stack. A protective layer is deposited over the TMR stack. Another etch process is performed to remove the protective layer such that a portion of the second magnetic layer is exposed from the protective layer and a spacer is formed from a remaining portion of the protective layer. The spacer surrounds sidewalls of the first magnetic layer and the tunnel barrier layer. The portion of the second magnetic layer exposed from the protective layer is removed so that a TMR sensor element remains, where the TMR sensor element includes a bottom magnet, a top magnet, and a tunnel junction.

1 - 15  (canceled). 
     
     
         16 . A tunnel magnetoresistance (TMR) sensor element comprising:
 a TMR stack, said TMR stack including:
 a bottom magnet; 
 a tunnel junction formed on said bottom magnet; 
 a top magnet formed on said tunnel junction; and 
 a spacer fully surrounding sidewalls of said top magnet and said tunnel junction; and 
   an electrode interposed between said bottom magnet and a surface of an active silicon substrate, a section of said electrode extending laterally on said surface of the active silicon substrate beyond said bottom magnet such that said section of said electrode is exposed from said bottom magnet.   
     
     
         17 . The TMR sensor element of  claim 16  wherein said spacer comprises at least one of a silicon nitride, silane-based silicon oxide, and a tetraethylorthosilicate (TEOS) oxide material. 
     
     
         18 . The TMR sensor element of  claim 16  wherein said bottom magnet includes a step region that extends laterally relative to said top magnet and said tunnel junction by a distance defined by a lateral thickness of said spacer, and said spacer resides on said step region. 
     
     
         19 . The TMR sensor element of  claim 16  wherein:
 said top magnet comprises a free layer of said TMR sensor element; and 
 said bottom magnet comprises a reference layer of said TMR sensor element. 
 
     
     
         20 . The TMR sensor element of  claim 16  wherein:
 said top magnet comprises a reference layer of said TMR sensor element; and 
 said bottom magnet comprises a free layer of said TMR sensor element.