# US 8,785,902 B2 · Resistive memory device and method for fabricating the same

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- Number: US 8,785,902 B2
- Document ID: US8785902B2
- Status: Granted
- Kind: B2
- Application number: 13/947,821
- Filed: 2013-07-22
- Published: 2013-11-28
- Granted: 2014-07-22
- Earliest claimed: 2010-01-21
- Assignees: SK hynix Inc.
- Applicants: SK hynix Inc.
- Inventors: Seok-Pyo Song; Yu-Jin Lee
- Web page: https://patentgrep.com/patent/US8785902B2

## CPC

- H10N 70/8418: {adapted for focusing electric field or current, e.g. tip-shaped}
- H10B 63/20: {comprising selection components having two electrodes, e.g. diodes}
- H10N 70/011: {Manufacture or treatment of multistable switching devices}
- H10N 70/20: Multistable switching devices, e.g. memristors
- H10N 70/231: {based on solid-state phase change, e.g. between amorphous and crystalline phases, Ovshinsky effect}
- H10N 70/826: {adapted for essentially vertical current flow, e.g. sandwich or pillar type devices}
- H10N 70/8265: {on sidewalls of dielectric structures, e.g. mesa-shaped or cup-shaped devices}
- H10N 70/841: {Electrodes}
- G11C 13/00: Digital stores characterised by the use of storage elements not covered by groups G11C11/00, G11C23/00, or G11C25/00
- G11C 2213/52: Structure characterized by the electrode material, shape, etc.
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10B: ELECTRONIC MEMORY DEVICES
- G11C: STATIC STORES (semiconductor memory devices H10B)

## Abstract

A resistive memory device includes a lower electrode formed on a substrate, a resistive layer formed on the lower electrode, and an upper electrode on the resistive layer, wherein a lower portion of the upper electrode is narrower than an upper portion of the upper electrode.

## Claims

### Claim 1

A resistive memory device comprising:
a lower electrode formed over a substrate;
a sacrificial layer formed over the lower electrode;
a resistive layer buried in the sacrificial layer over the lower electrode; and
an upper electrode formed over the resistive layer,
wherein a top surface of the upper electrode protrudes higher than top surface of the resistive layer and the sacrificial layer, and
wherein the top surface of the upper electrode has a rounded profile.

### Claim 2 (depends on 1)

The resistive memory device of claim 1, further comprising:
a selection element fanned on the upper electrode; and
a selection electrode formed on the selection element.

### Claim 3 (depends on 1)

The resistive memory device of claim 1, wherein the upper electrode has a pillar shape in which a lower portion is narrower than an upper portion and the resistive layer surrounds a sidewall and the lower portion of the upper electrode.

### Claim 4 (depends on 3)

The resistive memory device of claim 3, wherein the upper electrode has a stepped sidewall having a width that is narrower at a lower portion thereof.

### Claim 5 (depends on 1)

The resistive memory device of claim 1, wherein a height of the top surface of the resistive layer is the same as a height of the top surface of the sacrificial layer.

### Claim 6 (depends on 1)

The resistive memory device of claim 1, wherein the entire top surface of the upper electrode protrudes above the entire top surfaces of the resistive layer and the sacrificial layer.

### Claim 7 (depends on 1)

The resistive memory device of claim 1, further comprising:
a selection element over the upper electrode; and
a selection electrode over the upper electrode, wherein the selection element and the selection electrode are configured to select the resistive memory device formed by the lower electrode, the resistive layer, and the upper electrode.

### Claim 8 (depends on 7)

The resistive memory device of claim 7, wherein the selection of the resistive memory includes turning on a connection to the resistive memory.

### Claim 9 (depends on 1)

The resistive memory device of claim 1, wherein the resistive layer comprises phase change materials or resistive variable materials.

### Claim 10

A resistive memory device comprising:
a lower electrode formed over a substrate;
a resistive layer formed over the lower electrode; and
an upper electrode formed over the resistive layer,
wherein a lower portion of the upper electrode is narrower than an upper portion of the upper electrode, and a top surface of the upper electrode has a rounded profile.