# US 8,541,770 B2 · Select devices including an open volume, memory devices and systems including same, and methods for forming same

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- Number: US 8,541,770 B2
- Document ID: US8541770B2
- Status: Granted
- Kind: B2
- Application number: 13/211,036
- Filed: 2011-08-16
- Published: 2011-12-08
- Granted: 2013-09-24
- Earliest claimed: 2008-11-19
- Assignees: Micron Technology, Inc.
- Applicants: Bhaskar Srinivasan; Gurtej S. Sandhu
- Inventors: Bhaskar Srinivasan; Gurtej S. Sandhu
- Web page: https://patentgrep.com/patent/US8541770B2

## CPC

- H10D 8/70: Tunnel-effect diodes
- H10B 99/16: {comprising memory cells having diodes}
- H10P 14/40: of conductive or resistive materials
- Y10S 438/957: Making metal-insulator-metal device
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10B: ELECTRONIC MEMORY DEVICES
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

Select devices including an open volume that functions as a high bandgap material having a low dielectric constant are disclosed. The open volume may provide a more nonlinear, asymmetric I-V curve and enhanced rectifying behavior in the select devices. The select devices may comprise, for example, a metal-insulator-insulator-metal (MIIM) diode. Various methods may be used to form select devices and memory systems including such select devices. Memory devices and electronic systems include such select devices.

## Claims

### Claim 1

A select device comprising:
a dielectric material on a conductive material;
another dielectric material on the dielectric material and extending substantially evenly beyond opposing side surfaces of the dielectric material;
another conductive material overlying the another dielectric material;
an open volume at least partially defined by a surface of the conductive material, an opposing surface of the another dielectric material, the opposing side surfaces of the dielectric material, and surfaces of spacers substantially coplanar with sidewalls of the another conductive material and the another dielectric material.

### Claim 2 (depends on 1)

The select device of claim 1, wherein the open volume is disposed about a periphery of the dielectric material.

### Claim 3 (depends on 1)

The select device of claim 1, wherein the open volume has a thickness of less than about 1 nm.

### Claim 4 (depends on 1)

The select device of claim 1, wherein the open volume has a thickness of from about 5 Å to about 20 Å.

### Claim 5 (depends on 1)

The select device of claim 1, wherein the another dielectric material comprises a material having a dielectric constant of from about 2 to about 10, and having a band gap of from about 6 eV to about 10 eV.

### Claim 6 (depends on 1)

The select device of claim 1, wherein the conductive material consists of at least one of tantalum silicide, an alloy of tantalum and silicon, and an alloy of tantalum and nitrogen.

### Claim 7 (depends on 1)

The select device of claim 1, wherein the another conductive material comprises at least one of platinum, titanium, titanium nitride, rhodium, iridium, and ruthenium.

### Claim 8 (depends on 1)

The select device of claim 1, wherein the conductive material consists of tantalum nitride, the another conductive material comprises platinum, and the another dielectric material comprises amorphous carbon.

### Claim 9 (depends on 8)

The select device of claim 8, wherein the dielectric material comprises silicon dioxide.

### Claim 10 (depends on 1)

The select device of claim 1, wherein the open volume substantially extends between the spacers.

### Claim 11 (depends on 1)

The select device of claim 1, wherein the conductive material overlies a semiconductor material.

### Claim 12 (depends on 1)

The select device of claim 1, wherein the spacers are disposed between the open volume and an additional dielectric material.

### Claim 13 (depends on 1)

The select device of claim 1, wherein the conductive material comprises at least one of tantalum silicide, and an alloy of tantalum and silicon.

### Claim 14 (depends on 1)

The select device of claim 1, wherein the dielectric material comprises hafnium oxide and zirconium oxide.

### Claim 15 (depends on 1)

The select device of claim 1, wherein a thickness of the another dielectric material is between about 2 nanometers and about 8 nanometers.

### Claim 16 (depends on 1)

The select device of claim 1, wherein a thickness of the another conductive material is between about 5 nanometers and about 30 nanometers.

### Claim 17

A memory device comprising:
at least one memory element;
a plurality of bit lines;
at least one wordline; and
at least one select device comprising:
a conductive material;
a dielectric material on the conductive material;
another dielectric material on the dielectric material and extending substantially the same distance beyond opposing side surfaces of the dielectric material;
another conductive material over the another dielectric material; and
an open volume between the conductive material and the another dielectric material and at least partially defined by the opposing side surfaces of the dielectric material and surfaces of spacers substantially coplanar with sidewalls of the another conductive material and the another dielectric material.

### Claim 18 (depends on 17)

The memory device of claim 17, wherein the at least one select device has a lateral dimension of from about 25 nm to about 75 nm.

### Claim 19 (depends on 17)

The memory device of claim 17, wherein the conductive material consists of tantalum nitride, the another conductive material comprises platinum, and the another dielectric material comprises amorphous carbon.

### Claim 20

An electronic system comprising:
at least one electronic signal processor;
at least one memory device configured to communicate electrically with the at least one electronic signal processor, the at least one memory device comprising:
at least one select device comprising:
a conductive material;
a dielectric material on the conductive material;
another dielectric material on the dielectric material and substantially uniformly extending past opposing side surfaces of the dielectric material;
another conductive material over the another dielectric material;
an open volume extending between the another dielectric material and the conductive material and at least partially defined by the opposing side surfaces of the dielectric material and surfaces of spacers substantially coplanar with sidewalls of the another conductive material and the another dielectric material; and
at least one of an input device and an output device configured to communicate electrically with the at least one electronic signal processor.

### Claim 21 (depends on 20)

The electronic system of claim 20, wherein the conductive material comprises a metal having a first work function, and wherein the another conductive material comprises a metal having a second work function higher than the first work function.