Unlock instant, AI-driven research and patent intelligence for your innovation.

Magnetic random access memory

a random access and magnetic technology, applied in the field of magnetic random access memory, can solve the problem of high possibility of degrading the reliability of a devi

Inactive Publication Date: 2008-08-28
KK TOSHIBA
View PDF4 Cites 15 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention provides a magnetic random access memory that uses a magnetoresistive effect element with a fixed layer and a reversible recording layer. The non-magnetic layer between the fixed layer and recording layer is made of materials containing elements such as W, Mo, Ta, Ti, Zr, Nb, Cr, Hf, V, Co, and Ni. This results in a more efficient and reliable memory cell array.

Problems solved by technology

In such a structure, when high-temperature annealing at 500 to 700° C. is carried out after forming a magnetic tunnel junction (MTJ) film, reliability of a device is highly possibly degraded due to, e.g., occurrence of interfacial diffusion of a contact and a substrate.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Magnetic random access memory
  • Magnetic random access memory
  • Magnetic random access memory

Examples

Experimental program
Comparison scheme
Effect test

first embodiment

[1] First Embodiment

[0030]A first embodiment is an example where a contact and the like arranged below a magnetic tunnel junction (MTJ) element are formed of a material containing a refractory metal.

[0031][1-1] Structure

[0032]FIG. 1 is a cross-sectional view showing a magnetic random access memory according to a first embodiment of the present invention. A structure of a memory cell in the magnetic random access memory according to the first embodiment will now be explained hereinafter.

[0033]As shown in FIG. 1, an element isolation region (not shown) having a shallow trench isolation (STI) structure is formed in a semiconductor substrate (a silicon substrate) 1. A gate electrode 2 is formed on the semiconductor substrate 1 through a gate insulating film (not shown), and source / drain diffusion layers 3a and 3b are formed in the semiconductor substrate 1 on both sides of this gate electrode 2, thereby forming a transistor (e.g., an MOS transistor) Tr functioning as a switching element...

second embodiment

[2] Second Embodiment

[0076]A second embodiment is an example where an interconnect below the MTJ element in the first embodiment is also formed of a refractory metal. It is to be noted that, in the second embodiment, an explanation of the same points as those in the foregoing embodiment will be omitted.

[0077][2-1] Structure

[0078]FIG. 2 is a cross-sectional view of a magnetic random access memory according to the second embodiment of the present invention. A structure of the magnetic random access memory according to the second embodiment will now be explained.

[0079]As shown in FIG. 2, the second embodiment is different from the first embodiment in that an interconnect 6 pulled out in a direction parallel to a substrate surface is formed on a contact 4, a barrier metal film 7 is formed on a side surface and a bottom surface of this interconnect 6, and an MTJ element MTJ is formed on the interconnect 6.

[0080]Therefore, the interconnect 6 is arranged immediately below the MTJ element M...

third embodiment

[3] Third Embodiment

[0089]A third embodiment is an example where a lower electrode of the MTJ element in the first embodiment is likewise formed of a refractory metal. It is to be noted that, in the third embodiment, an explanation on the same points as those in each of the foregoing embodiments will be omitted.

[0090][3-1] Structure

[0091]FIG. 3 is a cross-sectional view of a magnetic random access memory according to the third embodiment of the present invention. A structure of the magnetic random access memory according to the third embodiment will now be explained hereinafter.

[0092]As shown in FIG. 3, the third embodiment is different from the first embodiment in that a lower electrode 8 pulled out in a direction parallel to a substrate surface is formed on a contact 4 and an MTJ element MTJ is formed on this lower electrode 8.

[0093]Therefore, the lower electrode 8 is arranged directly below the MTJ element MTJ, and a gate electrode 2 is arranged on a semiconductor substrate 11 be...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

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.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2007-047696, filed Feb. 27, 2007, the entire contents of which are incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to a magnetic random access memory including conductive layers each formed of a refractory metal.[0004]2. Description of the Related Art[0005]In a spin injection magnetization reversal type magnetic random access memory (MRAM), annealing must be performed at a high temperature of 350° C. or above in order to improve crystallinity of MgO in a tunnel insulating film and thereby increase the magnetoresistive ratio. Further, in some expected magnetic materials, especially perpendicular magnetic materials, an annealing temperature of approximately 500 to 700° C. is required to improve characteristics.[0006]However, in an interconnect structure as...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(United States)
IPC IPC(8): G11C11/14H10N50/10H10N50/80
CPCG11C11/16G11C11/161G11C11/1675H10B61/22H10N50/10H10N50/85H10B61/00H10N50/80
Inventor KAJIYAMA, TAKESHIASAO, YOSHIAKI
Owner KK TOSHIBA