MRAM tunnel barrier structure and methods
AssigneeEverspin Technologies, Inc.
InventorsPhillip Glenn Mather, Renu W. Dave, Frederick B. Mancoff
Life of this patent
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Abstract
A magnetic tunnel junction (MTJ) structure is of the type having a tunnel barrier positioned between a fixed ferromagnetic layer and a free ferromagnetic layer, the tunnel barrier includes a first barrier layer contacting either the fixed ferromagnetic layer or the free ferromagnetic layer. The first barrier layer transmits a high spin polarization and is selected from the group consisting of metal oxides, metal nitrides, and metal oxynitrides. The second barrier layer, which contacts the first barrier layer, has a low barrier height and is selected from the group consisting of metal oxides, metal nitrides, and metal oxynitrides.
Claims16
A magnetic tunnel junction (MTJ) structure of the type having a tunnel barrier positioned between a fixed ferromagnetic layer and a free ferromagnetic layer, the tunnel barrier comprising:
- a first barrier layer contacting either the fixed ferromagnetic layer or the free ferromagnetic layer, wherein the first barrier layer transmits a high spin polarization and is selected from the group consisting of metal oxides, metal nitrides, and metal oxynitrides;
- and
- a second barrier layer contacting the first barrier layer, wherein the second barrier layer has a barrier height of less than about 0.5 eV and comprises TiOx
- a third barrier layer formed on the second barrier layer and contacting the free ferromagnetic layer, the third barrier layer selected from the group consisting of metal oxides, metal nitrides, and metal oxynitrides,
- wherein the first barrier layer is formed on the fixed ferromagnetic layer and the second barrier layer is formed on the first barrier layer.
A method for fabricating a magnetic tunnel junction (MTJ) tunnel barrier between a fixed ferromagnetic layer and a free ferromagnetic layer, comprising:
- forming a first barrier layer such that it transmits a high spin polarization and is formed from a material selected from the group consisting of metal oxides, metal nitrides, and metal oxynitrides;
- forming a second barrier layer such that it has a barrier height of less than about 0.5 eV, contacts the first barrier layer, and comprises TiOx;
- and
- forming the fixed ferromagnetic layer and the free ferromagnetic layer such that at least one of the ferromagnetic layers contacts the first barrier layer.
A multi-layer MTJ structure comprising:
- a fixed ferromagnetic layer;
- a multilayer barrier structure located on the fixed ferromagnetic layer;
- a free ferromagnetic layer located on the multilayer barrier structure;
- wherein the multilayer barrier structure comprises a first, a second, a third, and a fourth barrier layer, and wherein the first and fourth barrier layers each transmit a high spin polarization and are selected from the group consisting of metal oxides, metal nitrides and metal oxynitrides, and the second barrier layer has a barrier height of less than about 0.5eV and comprises TiOx.
A method for fabricating a magnetic tunnel junction (MTJ) tunnel barrier between a fixed ferromagnetic layer and a free ferromagnetic layer, comprising:
- forming a first barrier layer comprising MgO on the fixed ferromagnetic layer such that it transmits a high spin polarization;
- forming a second barrier layer comprising TiOx on the first barrier layer;
- forming a third barrier layer comprising MgO on the second barrier layer;
- and
- forming the free ferromagnetic layer on the third barrier layer.
Dependencies are inferred from the claim text.