US 7,379,327 B2Granted

Current driven switching of magnetic storage cells utilizing spin transfer and magnetic memories using such cells having enhanced read and write margins

AssigneesGrandis, Inc., Renesas Technology Corp.

InventorsEugene Youjun Chen, Yiming Huai, Alex Fischer Panchula, Lien-Chang Wang, Xiao Luo

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Abstract

A method and system for providing a magnetic memory. The magnetic memory includes magnetic storage cells in an array, bit lines, and source lines. Each magnetic storage cell includes at least one magnetic element. The magnetic element(s) are programmable by write currents driven through the magnetic element(s). Each magnetic element has free and pinned layer(s) and a dominant spacer. The magnetic memory is configured such that either the read current(s) flow from the free layer(s) to the dominant spacer if the maximum low resistance state read current divided by the minimum low resistance state write current is greater than the maximum high resistance state read current divided by the minimum high resistance state write current or the read current(s) flow from the dominant spacer to the free layer(s) if the maximum low resistance state read current divided by the minimum low resistance state write current is less than the maximum high resistance state read current divided by the minimum high resistance state write current.

Claims25

Dependent claims

A magnetic memory comprising:

a plurality of magnetic storage cells in an array, each of the plurality of magnetic storage cells including at least one magnetic element, the at least one magnetic element being programmable by at least one write current driven through the magnetic element, each of the at least one magnetic element having at least one free layer, a dominant spacer, and at least one pinned layer, the plurality of magnetic storage cells having a maximum high resistance state read current, a maximum low resistance state read current, a minimum high resistance state write current, and a minimum low resistance state write current, the plurality of magnetic storage cells being read by at least one read current,
a plurality of bit lines corresponding to the plurality of magnetic storage cells;
and
a plurality of source lines corresponding to the plurality of magnetic storage cells;
wherein the plurality of magnetic storage cells, the plurality of source lines and the plurality of bit lines are configured such that at least one of the at least one read current flows from the at least one free layer to the dominant spacer if the maximum low resistance state read current divided by the minimum high resistance state write current is greater than the maximum high resistance state read current divided by the minimum low resistance state write current and the at least one read current flows from the dominant spacer to the at least one free layer if the maximum low resistance state read current divided by the minimum high resistance state write current is less than the maximum high resistance state read current divided by the minimum low resistance state write current.

2 more elements

A method for fabricating a magnetic memory comprising:

providing a plurality of magnetic storage cells in an array, each of the plurality of magnetic storage cells including at least one magnetic element, the at least one magnetic element being programmable by at least one write current driven through the magnetic element, each of the at least one magnetic element having at least one free layer, a dominant spacer, and at least one pinned layer, the plurality of magnetic storage cells having a maximum high resistance state read current, a maximum low resistance state read current, a minimum high resistance state write current, and a minimum low resistance state write current, the plurality of magnetic storage cells being read by at least one read current,
providing a plurality of bit lines corresponding to the plurality of magnetic storage cells;
providing a plurality of source lines corresponding to the plurality of magnetic storage cells;
and
providing a plurality of reference cell;
wherein the plurality of magnetic storage cells, the plurality of source lines and the plurality of bit lines are configured such that at least one of the at least one read current flows from the at least one free layer to the dominant spacer if the maximum low resistance state read current divided by the minimum high resistance state write current is greater than the maximum high resistance state read current divided by the minimum low resistance state write current and the at least one read current flows from the dominant spacer to the at least one free layer if the maximum low resistance state read current divided by the minimum high resistance state write current is less than the maximum high resistance state read current divided by the minimum low resistance state write current.

3 more elements

Dependencies are inferred from the claim text.