# US 8,772,750 B2 · Non-volatile memory elements and memory devices including the same

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- Number: US 8,772,750 B2
- Document ID: US8772750B2
- Status: Granted
- Kind: B2
- Application number: 13/115,549
- Filed: 2011-05-25
- Published: 2012-03-01
- Granted: 2014-07-08
- Earliest claimed: 2010-08-31
- Assignees: Samsung Electronics Co., Ltd.
- Applicants: Chang-bum Lee; Chang-jung Kim; Young-bae Kim; Myoung-jae Lee; Ji-hyun Hur; Dong-soo Lee; Man Chang; Seung-ryul Lee
- Inventors: Chang-bum Lee; Chang-jung Kim; Young-bae Kim; Myoung-jae Lee; Ji-hyun Hur; Dong-soo Lee; Man Chang; Seung-ryul Lee
- Web page: https://patentgrep.com/patent/US8772750B2

## CPC

- H10B 63/20: {comprising selection components having two electrodes, e.g. diodes}
- G11C 13/0007: {comprising metal oxide memory material, e.g. perovskites}
- H10B 63/84: {arranged in a direction perpendicular to the substrate, e.g. 3D cell arrays}
- H10N 70/24: {based on migration or redistribution of ionic species, e.g. anions, vacancies}
- H10N 70/826: {adapted for essentially vertical current flow, e.g. sandwich or pillar type devices}
- H10N 70/841: {Electrodes}
- H10N 70/8833: {Binary metal oxides, e.g. TaOx}
- G11C 2213/51: Structure including a barrier layer preventing or limiting migration, diffusion of ions or charges or formation of electrolytes near an electrode
- G11C 2213/55: Structure including two electrodes, a memory active layer and at least two other layers which can be a passive or source or reservoir layer or a less doped memory active layer
- G11C 2213/56: Structure including two electrodes, a memory active layer and a so called passive or source or reservoir layer which is NOT an electrode, wherein the passive or source or reservoir layer is a source of ions which migrate afterwards in the memory active layer to be only trapped there, to form conductive filaments there or to react with the material of the memory active layer in redox way
- G11C 2213/72: Array wherein the access device being a diode
- H10B: ELECTRONIC MEMORY DEVICES
- G11C: STATIC STORES (semiconductor memory devices H10B)
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR

## Abstract

A non-volatile memory element includes: a memory layer disposed between a first electrode and a second electrode; and a buffer layer disposed between the memory layer and the first electrode. The memory layer includes a first material layer and a second material layer. The first material layer and the second material layer are configured to exchange ionic species to change a resistance state of the memory layer.

## Claims

### Claim 1

A non-volatile memory element comprising:
a memory layer disposed between a first electrode and a second electrode, the memory layer including a first material layer and a second material layer configured to exchange ionic species to change a resistance state of the memory layer; and a buffer layer disposed between the memory layer and the first electrode; wherein
the first material layer is an oxygen supplying layer and the second material layer is an oxygen exchanging layer,
an oxygen concentration of the oxygen exchanging layer increases one of gradually and in stages in a direction from the oxygen supplying layer to the second electrode,
the oxygen exchanging layer includes a first region having a first oxygen concentration and a second region having a second oxygen concentration, the second oxygen concentration being greater than the first oxygen concentration,
the first region is in direct contact with the oxygen supplying layer, and
the second region is in direct contact with the second electrode.

### Claim 2 (depends on 1)

The non-volatile memory element of claim 1, wherein the oxygen supplying layer is formed of a first metal oxide.

### Claim 3 (depends on 2)

The non-volatile memory element of claim 2, wherein the first metal oxide includes at least one of Ta oxide, Ti oxide, Zr oxide, yttria-stabilized zirconia (YSZ), Hf oxide, Mn oxide, Mg oxide, and a combination thereof.

### Claim 4 (depends on 3)

The non-volatile memory element of claim 3, wherein the first metal oxide includes TaOx, wherein 0<x<2.5.

### Claim 5 (depends on 2)

The non-volatile memory element of claim 2, wherein the oxygen exchanging layer is formed of a second metal oxide.

### Claim 6 (depends on 5)

The non-volatile memory device of claim 5, wherein the second metal oxide is formed of an oxide from the same group as the first metal oxide or a different group from the first metal oxide.

### Claim 7 (depends on 6)

The non-volatile memory element of claim 6, wherein the second metal oxide includes at least one of Ta oxide, Ti oxide, Zr oxide, yttria-stabilized zirconia (YSZ), Hf oxide, Mn oxide, Mg oxide, and a combination thereof.

### Claim 8 (depends on 1)

The non-volatile memory element of claim 1, wherein the oxygen concentration of the oxygen exchanging layer is greater than an oxygen concentration of the oxygen supplying layer.

### Claim 9 (depends on 1)

The non-volatile memory element of claim 1, wherein an oxygen mobility of the oxygen exchanging layer is greater than or equal to an oxygen mobility of the oxygen supplying layer.

### Claim 10 (depends on 1)

The non-volatile memory element of claim 1, wherein the oxygen concentration of the oxygen exchanging layer varies gradually in the direction in which the oxygen exchanging layer is deposited.

### Claim 11 (depends on 1)

The non-volatile memory element of claim 1, wherein the oxygen concentration of the oxygen exchanging layer varies in stages in the direction in which the oxygen exchanging layer is deposited.

### Claim 12 (depends on 1)

The non-volatile memory element of claim 1, wherein the first region of the oxygen exchanging layer is disposed on the oxygen supplying layer and the second region of the oxygen exchanging layer is disposed between the first region and the second electrode.

### Claim 13 (depends on 1)

The non-volatile memory element of claim 1, wherein the buffer layer includes a material that increases a potential barrier between the first electrode and the memory layer.

### Claim 14 (depends on 1)

The non-volatile memory element of claim 1, wherein the buffer layer includes a material having an interatomic bonding energy greater than an interatomic bonding energy of the memory layer.

### Claim 15 (depends on 1)

The non-volatile memory element of claim 1, wherein the buffer layer includes at least one of AlOx, SiOx, SiNx, ZrOx, HfOx, and a combination thereof.

### Claim 16 (depends on 1)

The non-volatile memory element of claim 1, wherein the first electrode is formed of one of a base metal and a conductive oxide.

### Claim 17 (depends on 1)

The non-volatile memory element of claim 1, wherein the first electrode includes at least one of W, Ni, Al, Ti, Ta, TiN, TiW, TaN, IZO, ITO, IrO2, Ir, Ru, Pd, Au, and Pt.

### Claim 18 (depends on 1)

The non-volatile memory element of claim 1, wherein the second electrode includes at least one of IrO2, Ir, Ru, Pd, Au, and Pt.

### Claim 19 (depends on 18)

The non-volatile memory element of claim 18, wherein the second electrode is formed of IrO2 or Ir.

### Claim 20 (depends on 1)

A memory device comprising: the non-volatile memory element of claim 1.

### Claim 21 (depends on 20)

The memory device of claim 20, further comprising:
a switching element connected to the non-volatile memory element.

### Claim 22

A memory device comprising:
a plurality of first wirings arranged in parallel with one another;
a plurality of second wirings crossing the first wirings and arranged in parallel with one another; and
a first memory cell formed at each cross-point between the plurality of first wirings and the plurality of second wirings, each first memory cell including,
a memory layer disposed between the first wiring and the second wiring, and including a first material layer and a second material layer configured to exchange ionic species to change a resistance state of the memory layer, and
a buffer layer disposed between the memory layer and the first wiring; wherein
the first material layer is an oxygen supplying layer and the second material layer is an oxygen exchanging layer,
an oxygen concentration of the oxygen exchanging layer increases one of gradually and in stages in a direction from the oxygen supplying layer to the second wiring,
the oxygen exchanging layer includes a first region having a first oxygen concentration and a second region having a second oxygen concentration, the second oxygen concentration being greater than the first oxygen concentration,
the first region is in direct contact with the oxygen supplying layer, and
the second region is in direct contact with an intermediate electrode disposed between the first wiring and the second wiring.

### Claim 23 (depends on 22)

The memory device of claim 22, wherein each first memory cell further comprises a switching element disposed between the memory layer and the second wiring, and wherein the intermediate electrode is disposed between the memory layer and the switching element.

### Claim 24 (depends on 22)

The memory device of claim 22, wherein the oxygen supplying layer is formed of a first metal oxide and the oxygen exchanging layer is formed of a second metal oxide, the second metal oxide being formed of an oxide from a same group as the first metal oxide.

### Claim 25 (depends on 22)

The memory device of claim 22, wherein the oxygen supplying layer is formed of a first metal oxide, and the oxygen exchanging layer is formed of a second metal oxide, the second metal oxide being an oxide of a different group from the first metal oxide.

### Claim 26 (depends on 22)

The memory device of claim 22, wherein the oxygen supplying layer is formed of a first metal oxide including at least one of Ta oxide, Ti oxide, Zr oxide, yttria-stabilized zirconia (YSZ), Hf oxide, Mn oxide, Mg oxide, and a combination thereof.

### Claim 27 (depends on 26)

The memory device of claim 26, wherein the first metal oxide includes TaOx, wherein 0<x<2.5.

### Claim 28 (depends on 22)

The memory device of claim 22, wherein the oxygen exchanging layer is formed of a second metal oxide including at least one of Ta oxide, Ti oxide, Zr oxide, yttria-stabilized zirconia (YSZ), Hf oxide, Mn oxide, Mg oxide, and a combination thereof.

### Claim 29 (depends on 22)

The memory device of claim 22, wherein an oxygen concentration of the oxygen exchanging layer varies in a direction in which the oxygen exchanging layer is deposited.

### Claim 30 (depends on 29)

The memory device of claim 29, wherein the oxygen concentration of the oxygen exchanging layer varies one of gradually and in stages in the direction in which the oxygen exchanging layer is deposited.

### Claim 31 (depends on 22)

The memory device of claim 22, wherein the buffer layer includes at least one of AlOx, SiOx, SiNx, ZrOx, HfOx, and a combination thereof.

### Claim 32 (depends on 22)

The memory device of claim 22, wherein the first wiring includes at least one of W, Ni, Al, Ti, Ta, TiN, TiW, TaN, IZO, ITO, IrO2, Ir, Ru, Pd, Au, and Pt.

### Claim 33 (depends on 22)

The memory device of claim 22, wherein an electrode contacts the memory layer, and the electrode includes at least one of IrO2, Ir, Ru, Pd, Au, and Pt.

### Claim 34 (depends on 22)

The memory device of claim 22, further comprising:
a plurality of third wirings arranged to cross the plurality of second wirings; and
a second memory cell formed at each cross-point between the plurality of second wirings and the plurality of third wirings.

### Claim 35 (depends on 34)

The memory device of claim 34, wherein the second memory cell has a different structure than the first memory cell.

### Claim 36 (depends on 34)

The memory device of claim 34, wherein the second memory cell has a same structure as the first memory cell.