Magnetoresistance effect device and method of production of the same

Abstract

A magnetoresistance effect device including a multilayer structure having a pair of ferromagnetic layers and a barrier layer positioned between them, wherein at least one ferromagnetic layer has at least the part contacting the barrier layer made amorphous and the barrier layer is an MgO layer having a highly oriented texture structure.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a magnetoresistance effect device and a method of production of the same, more particularly relates to a magnetoresistance effect device fabricated utilizing a simple sputtering film-formation method and having an extremely high magnetoresistance ratio and a method of production of the same. [0003] 2. Description of the Related Art [0004] In recent years, as nonvolatile memories, magnetic memory devices called “magnetoresistive random access memories (MRAMs)” have come into attention and have started entering the commercial stage. MRAMs are simple in structure, so ultra-high density integration to the gigabit level is easy. In MRAMs, the relative orientation of the magnetic moment is utilized to create the storage action. As the result, the number of possible re-writability is extremely high and the operating speed can be reduced to the nanosecond level. [0005]FIG. 4 shows the struct...

AI Technical Summary

Benefits of technology

[0016] According to above magnetoresistance effect device, since the barrier layer has a single crystal or highly oriented fiber-texture structure, the flow of current between the ferromagnetic layers can be made straight and the MR ratio can be made an extremely high value.

[0017] In the magnetoresistance effect device, preferably the MgO layer is a single crystal layer formed by the sputtering method. However, an MgO layer with highly oriented fiber-texture structure also yield excellent properties. According to this configuration, the intermediate barrier layer can be produced simply. This is suitable for mass production.

[0018] In the magnetoresistance effect device, preferably the MgO layer is a single crystal layer formed using an MgO target and the sputtering method. The MgO layer can also be a highly oriented fiber-texture structure.

[0019] In the magnetoresistance effect device, preferably the ferromagnetic layers are CoFeB layers.

[0020] The method of production of a magnetoresistance effect device is a method of production of a magnetoresistance effect device including a multilayer structure comprised of a pair of ferromagnetic layers and a barrier layer positioned between them, comprising forming at least one ferromagnetic layer so that at least at least the part contacting the barrier layer is amorphous and forming the barrier layer having a single crystal or highly oriented fiber-texture structure by using the sputtering method. Further, in the method of production of a magnetoresistance effect device, preferably the MgO layer is formed by RF magnetron sputtering using an MgO target.

[0021] According to the present invention, since the tunnel barrier layer forming the intermediate layer of the TMR device or other magnetoresistance effect device is an MgO layer having a single crystal or highly oriented fiber-texture structure, the MR ratio can be made extremely high. When using this as a memory device of an MRAM, a gigabit class ultra-high integrated MRAM can be realized. Further, by forming the a single crystal or highly oriented fiber-texture MgO layer by the sputtering method, it is possible to fabricate a magnetoresistance effect device suitable for mass production and having high practical applicability.

Problems solved by technology

Further, epitaxial growth of an Fe film by an expensive MBE device, formation of an MgO film by ultrahigh vacuum electron beam evaporation and other sophisticated film deposition technology are required.

There is the problem that the longer the film deposition time, the less suitable the process for mass production.

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