# US 12,004,435 B2 · Tunable resistive random access memory cell

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 12,004,435 B2
- Document ID: US12004435B2
- Status: Granted
- Kind: B2
- Application number: 17/804,912
- Filed: 2022-06-01
- Published: 2023-12-07
- Granted: 2024-06-04
- Earliest claimed: 2022-06-01
- Assignees: International Business Machines Corporation
- Applicants: International Business Machines Corporation
- Inventors: Min Gyu Sung; Soon-Cheon Seo; Chanro Park
- Web page: https://patentgrep.com/patent/US12004435B2

## CPC

- H10N 70/8418: {adapted for focusing electric field or current, e.g. tip-shaped}
- H10B 63/30: {comprising selection components having three or more electrodes, e.g. transistors}
- H10N 70/063: {by etching of pre-deposited switching material layers, e.g. lithography}
- H10N 70/066: {by filling of openings, e.g. damascene method}
- H10N 70/828: {Current flow limiting means within the switching material region, e.g. constrictions}
- H10N 70/8833: {Binary metal oxides, e.g. TaOx}
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10B: ELECTRONIC MEMORY DEVICES

## Abstract

A method of manufacturing an RRAM cell includes forming a first wire, forming an insulator on the first wire, the insulator having a pore and an insulator surface, and forming a first electrode layer on the first wire and the insulator, the first electrode having an electrode surface. The method further includes recessing the first electrode layer such that the electrode surface is recessed toward the first wire from the insulator surface, forming a switching layer on the insulator and the first electrode, and forming a second electrode on the switching layer.

## Claims

### Claim 1

A method of manufacturing a resistive random access memory (RRAM) cell, the method comprising:
forming a first wire;
forming an insulator on the first wire, the insulator having a pore and an insulator surface;
forming a first electrode layer on the first wire and the insulator, the first electrode having an electrode surface;
recessing the first electrode layer such that the electrode surface is recessed toward the first wire from the insulator surface;
forming a switching layer on the insulator and the first electrode; and
forming a second electrode on the switching layer.

### Claim 2 (depends on 1)

The method of claim 1, further comprising forming a plug in the first electrode layer prior to recessing the first electrode layer, the plug having a plug surface that is recessed toward the first wire from the insulator surface.

### Claim 3 (depends on 2)

The method of claim 2, further comprising removing the plug prior to forming the switching layer.

### Claim 4 (depends on 2)

The method of claim 2, wherein:
the switching layer is comprised of a transition metal oxide material; and
the plug is comprised of an organic planarization layer material.

### Claim 5 (depends on 1)

The method of claim 1, further comprising forming a plug layer on the first electrode layer prior to recessing the first electrode layer.

### Claim 6 (depends on 5)

The method of claim 5, wherein recessing the first electrode layer uses a process that is selective for the first electrode layer compared to the plug layer.

### Claim 7 (depends on 5)

The method of claim 5, further comprising recessing the plug layer to form a plug prior to recessing the first electrode layer.

### Claim 8 (depends on 7)

The method of claim 7, wherein recessing the plug layer uses a process that is selective for the plug layer compared to the first electrode layer.

### Claim 9 (depends on 8)

The method of claim 8, further comprising removing the plug after recessing the first electrode layer.

### Claim 10 (depends on 1)

The method of claim 1, further comprising removing excess portions of the switching layer and the second electrode.

### Claim 11 (depends on 10)

The method of claim 10, further comprising forming a second insulator on the first insulator, the switching layer, and the second electrode.

### Claim 12 (depends on 1)

The method of claim 1, further comprising forming a second wire that is electrically connected to the second electrode.

### Claim 13

A resistive random access memory (RRAM) cell comprising:
a first electrode;
a switching layer electrically connected to the first electrode;
a second electrode electrically connected to the switching layer;
wherein the switching layer has a stepped-bell shape comprising:
a cup portion having a U-shape;
a rim portion having an L-shape and being connected to the cup portion; and
a disc portion having a flat shape and being connected to the rim portion.

### Claim 14 (depends on 13)

The RRAM cell of claim 13, further comprising:
a first insulator laterally surrounding the first electrode, the first insulator having an insulator surface;
a second insulator laterally surrounding the second electrode;
wherein the first electrode includes an electrode surface that is recessed from the insulator surface.

### Claim 15 (depends on 14)

The RRAM cell of claim 14, wherein:
the cup portion is in direct contact with solely the first electrode and the second electrode;
the rim portion is in direct contact with the first electrode, the second electrode, and the first insulator; and
the disc portion is in direct contact with the second electrode, the second insulator, and the insulator surface of the first insulator.

### Claim 16 (depends on 13)

The RRAM cell of claim 13, further comprising:
a first wire electrically connected to the first electrode; and
a second wire electrically connected to the second electrode.

### Claim 17 (depends on 16)

An integrated circuit comprising the RRAM cell of claim 16.

### Claim 18

A method of manufacturing a resistive random access memory (RRAM) cell, the method comprising:
forming a first wire;
forming an insulator on the first wire, the insulator having a pore and an insulator surface;
forming a first electrode on the first wire and the insulator, the first electrode having an electrode surface;
forming a plug in the first electrode the first electrode layer, the plug having a plug surface, wherein the electrode surface and the plug surface are recessed toward the first wire from the insulator surface;
removing the plug;
forming a switching layer on the insulator and the first electrode; and
forming a second electrode on the switching layer.

### Claim 19 (depends on 18)

The method of claim 18, wherein:
the plug is comprised of an organic planarization layer material; and
the switching layer is comprised of a transition metal oxide material.

### Claim 20 (depends on 18)

The method of claim 18, wherein forming the first electrode comprises:
forming an electrode layer; and
recessing the electrode layer to form the first electrode prior to removing the plug.