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Magnetic random access memory

A technology of random access memory and storage unit, which is applied in static memory, digital memory information, information storage and other directions, and can solve problems such as inability to read data.

Inactive Publication Date: 2005-04-13
KK TOSHIBA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

As a result, there is a problem that correct data cannot be read under wide operating conditions.

Method used

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  • Magnetic random access memory
  • Magnetic random access memory
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Examples

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no. 2 Embodiment

[0209] In the first embodiment described above, it is proposed to use a plurality of magnetoresistive elements to form a reference cell having an MR ratio half of that of the memory cell, and to flow a constant current through the reference cell to generate the reference potential Vref used for reading. Methods. Here, the respective magnetoresistive elements are basically formed with the same steps and the same layout as magnetoresistive elements used in memory cells.

[0210] However, since the reference cell is formed by combining a plurality of magneto-resistive elements, wiring for connecting the respective magneto-resistive elements is required, and the structure as a whole is different from that of the magneto-resistive elements of the memory cell. In addition, considering the layout of the memory cell array and peripheral circuits, it is difficult to arrange the reference cell in exactly the same environment as the magnetoresistive element in the memory cell.

[0211] ...

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Abstract

The bias voltage generating circuit (21) has a series circuit composed of a magnetoresistive element (Rref) and a MOS transistor (QN3). The MR ratio of the magnetoresistive element (Rref) in the series circuit is set to half the MR ratio of the magnetoresistive element in the memory cell. The adjustment resistor (r) has a resistance value half that of the wiring resistance of the bit line. A bias voltage generating circuit (21) supplies a bias voltage (Vbias) to a read current source. When a constant current flows through the bias voltage generating circuit (21), the read current source supplies a read current equal to the constant current to the bit line.

Description

technical field [0001] This invention relates to magnetic random access memories, and more particularly to sense amplifiers for amplifying data in memory cells. Background technique [0002] In recent years, as researchers have discovered that a magnetic tunnel junction (MTJ) has a large magnetoresistance (MR) ratio at room temperature, the realization of an MRAM using a tunnel magnetoresistance (TMR) effect has gradually become a reality. [0003] Before applying the TMR effect to the MRAM, there is known an MRAM using the giant magnetoresistance (Giant Magneto-Resistance, GMR) effect. However, the MR ratio of the MRAM to which the GMR effect is applied is from several percent to about 10% at the most. In addition, in the MRAM to which the GMR effect is applied, since a current flows through a low-resistance metal thin film, there is a problem that the signal amount is extremely small (several mV). [0004] In addition, in MRAM to which the GMR effect is applied, since th...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G11C11/14G11C11/15G11C11/16H01L43/08H10B20/00
CPCG11C11/16G11C11/1673G11C11/1655G11C7/065G11C11/161G11C11/15
Inventor 伊藤洋
Owner KK TOSHIBA