MAGNETORESISTIVE ELEMENT HAVING A NOVEL CAP MULTILAYER

摘要

A magnetoresistive element comprises a novel Boron-absorbing cap multilayer provided on the top surface of an amorphous CoFeB (or CoB, FeB) ferromagnetic recording layer. As the magnetoresistive film is thermally annealed, a crystallization process occurs to form bcc CoFe grains having epitaxial growth with (100) plane parallel to the surface of the tunnel barrier layer as Boron elements migrate into the novel cap layer. Removing the top portion of the cap layer by means of sputtering etch or RIE etch processes followed by optional oxidization process, a thin thermally stable portion of cap layer is remained on top of the recording layer with low damping constant. Accordingly, a reduced write current is achieved for spin-transfer torque MRAM application.

主权项

1. A magnetoresistive element comprising:
a reference layer having magnetic anisotropy and having an invariable magnetization direction; a tunnel barrier layer provided on the reference layer; a recording layer provided on the tunnel barrier layer and having a variable magnetization direction; a cap layer provided on top surface of the recording layer; a protective layer provided on top surface of the cap multilayer, wherein the protective layer and at least the top portion of the cap multilayer are later removed by an etching process after conducting a thermal annealing process on the magnetoresistive film and leaves a thermally stable bottom cap layer interfacing to the recording layer; an optional oxidization process provided to oxidize the top surface of the remained cap layer; and an upper-contact multilayer provided on the remained cap layer, comprising a buffer layer and a photoresist layer for further photo-lithographic processes of a magnetoresistive element.