Magnetic random access memory

Abstract

A magnetic random access memory which is a memory cell array including a magnetoresistive effect element having a fixed layer whose magnetization direction is fixed, a recording layer whose magnetization direction is reversible, and a non-magnetic layer provided between the fixed layer and the recording layer, wherein all conductive layers in the memory cell array arranged below the magnetoresistive effect element are formed of materials each containing an element selected from a group including W, Mo, Ta, Ti, Zr, Nb, Cr, Hf, V, Co, and Ni.

1 . A magnetic random access memory which is a memory cell array comprising a magnetoresistive effect element having a fixed layer whose magnetization direction is fixed, a recording layer whose magnetization direction is reversible, and a non-magnetic layer provided between the fixed layer and the recording layer,
 wherein all conductive layers in the memory cell array arranged below the magnetoresistive effect element are formed of materials each containing an element selected from a group including W, Mo, Ta, Ti, Zr, Nb, Cr, Hf, V, Co, and Ni.   
   
   
       2 . The memory according to  claim 1 , further comprising:
 a contact which is included in the conductive layer, placed immediately below the magnetoresistive effect element, and directly connected with the magnetoresistive effect element; and   a barrier metal film which is included in the conductive layer and formed on a side surface and a bottom surface of the contact.   
   
   
       3 . The memory according to  claim 2 ,
 wherein the contact is formed of W, and   the barrier metal film is formed of one of Ti, Ta, a compound containing Ti, a compound containing Ta, and a laminated layer including these materials.   
   
   
       4 . The memory according to  claim 1 , further comprising:
 an interconnect which is included in the conductive layer, placed below the magnetoresistive effect element, and directly connected with the magnetoresistive effect element;   a first barrier metal film which is included in the conductive layer and formed on a side surface and a bottom surface of the interconnect;   a contact which is included in the conductive layer, placed below the interconnect, and connected with the interconnect; and   a second barrier metal film which is included in the conductive layer and formed on a side surface and a bottom surface of the contact.   
   
   
       5 . The memory according to  claim 4 ,
 wherein the interconnect is formed of W or Ta,   the contact is formed of W, and   each of the first and second barrier metal films is formed of one of Ti, Ta, a compound containing Ti, a compound containing Ta, and a laminated layer including these materials.   
   
   
       6 . The memory according to  claim 1 , further comprising:
 a first contact which is included in the conductive layer, placed immediately below the magnetoresistive effect element, and directly connected with the magnetoresistive effect element;   a first barrier metal film which is included in the conductive layer and formed on a side surface and a bottom surface of the first contact;   a second contact which is placed immediately above the magnetoresistive effect element, directly connected with the magnetoresistive effect element, and formed of a material containing a refractory metal; and   a second barrier metal film which is formed on a side surface and a bottom surface of the second contact and formed of a material containing a refractory metal.   
   
   
       7 . The memory according to  claim 1 , further comprising:
 a contact which is included in the conductive layer, placed immediately below the magnetoresistive effect element, and directly connected with the magnetoresistive effect element;   a first barrier metal film which is included in the conductive layer and formed on a side surface and a bottom surface of the contact; and   a second barrier metal film which is included in the conductive layer, formed on a top face alone of the contact, and has a side surface that is in contact with a side surface of the first barrier metal film.   
   
   
       8 . The memory according to  claim 7 ,
 wherein a material of the first barrier metal film is the same as a material of the second barrier metal film.   
   
   
       9 . The memory according to  claim 7 ,
 wherein a film thickness of the first barrier metal film is larger than a film thickness of the second barrier metal film.   
   
   
       10 . The memory according to  claim 1 , further comprising:
 a contact which is included in the conductive layer, placed immediately below the magnetoresistive effect element, and directly connected with the magnetoresistive effect element;   a first barrier metal film which is included in the conductive layer and formed on a side surface and a bottom surface of the contact; and   a second barrier metal film which is included in the conductive layer and formed on top faces of the contact and the first barrier metal film.   
   
   
       11 . The memory according to  claim 1 , further comprising:
 a contact which is included in the electromagnetic layer, placed immediately below the magnetoresistive effect element, and directly connected with the magnetoresistive effect element;   a first barrier metal film which is included in the electromagnetic layer and formed on a bottom surface alone of the contact; and   a second barrier metal film which is included in the conductive layer and formed on a top face alone of the contact.   
   
   
       12 . The memory according to  claim 1 , further comprising:
 a contact which is included in the conductive layer, placed immediately below the magnetoresistive effect element, connected with the recording layer, and has a contact area with respect to the recording layer being smaller than an area of the recording layer.   
   
   
       13 . The memory according to  claim 12 , further comprising:
 a cap layer which is included in the conductive layer, provided between the recording layer and the contact, and has a resistance higher than a resistance of the recording layer.   
   
   
       14 . The memory according to  claim 13 ,
 wherein an area of a surface of the cap layer on the contact side is larger than an area of a surface of the contact on the cap layer side.   
   
   
       15 . The memory according to  claim 1 , further comprising:
 a first contact which is included in the conductive layer, placed immediately below the magnetoresistive effect element, and connected with one end of the magnetoresistive effect element; and   a second contact which is included in the conductive layer, placed immediately above the magnetoresistive effect element, and connected with the other end of the magnetoresistive effect element,   wherein at least one of the first and second contacts has a contact area with respect to the magnetoresistive effect element being smaller than an area of the recording layer.   
   
   
       16 . The memory according to  claim 5 , further comprising:
 a first cap layer which is included in the conductive layer, provided between the one end of the magnetoresistive effect element and the first contact, and has a resistance higher than a resistance of the recording layer; and   a second cap layer which is included in the electromagnetic layer, provided between the other end of the magnetoresistive effect element and the second contact, and has a resistance higher than a resistance of the recording layer.   
   
   
       17 . The memory according to  claim 1 ,
 wherein the magnetization directions of the fixed layer and the recording layer enter a parallel state or an anti-parallel state in accordance with a direction of a current passed to a space between the fixed layer and the recording layer.   
   
   
       18 . The memory according to  claim 1 ,
 wherein magnetizations of the fixed layer and the recording layer face a direction perpendicular to a film surface.   
   
   
       19 . The memory according to  claim 1 ,
 wherein the non-magnetic layer is MgO.   
   
   
       20 . The memory according to  claim 1 , further comprising:
 a first interconnect which is arranged above the magnetoresistive effect element and extended in a first direction; and   a second interconnect which is arranged below the magnetoresistive effect element, extended in a second direction crossing the first direction, and included in the conductive layer,   wherein the magnetoresistive effect element is arranged in a region where the first and second interconnects cross each other, and one of the first and second interconnects is connected with the magnetoresistive effect element.