# US 11,908,913 B2 · Semiconductor devices, transistors, and related methods for contacting metal oxide semiconductor devices

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- Number: US 11,908,913 B2
- Document ID: US11908913B2
- Status: Granted
- Kind: B2
- Application number: 17/661,187
- Filed: 2022-04-28
- Published: 2022-08-11
- Granted: 2024-02-20
- Earliest claimed: 2017-08-31
- Assignees: Micron Technology, Inc.
- Applicants: Micron Technology, Inc.
- Inventors: Durai Vishak Nirmal Ramaswamy; Ramanathan Gandhi; Scott E. Sills
- Web page: https://patentgrep.com/patent/US11908913B2

## CPC

- H10D 64/62: Electrodes ohmically coupled to a semiconductor
- H10D 30/0318: {of vertical TFTs}
- H10D 30/6728: {Vertical TFTs}
- H10D 30/6755: {Oxide semiconductors, e.g. zinc oxide, copper aluminium oxide or cadmium stannate}
- H10D 30/6756: {Amorphous oxide semiconductors}
- H10D 64/512: {Disposition of the gate electrodes, e.g. buried gates}
- H10D 99/00: Subject matter not provided for in other groups of this subclass
- H10B 12/05: {Making the transistor}
- H10B 12/30: {DRAM devices comprising one-transistor - one-capacitor [1T-1C] memory cells}
- H10D 30/63: Vertical IGFETs (H10D30/66 {, H10D30/6728, H10D30/689, H10D30/693} take precedence)
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10B: ELECTRONIC MEMORY DEVICES

## Abstract

A semiconductor device is disclosed. The semiconductor device includes a transistor including a source contact, a drain contact, and a channel region including an oxide semiconductor material as the channel material. At least one of the drain contact or the source contact includes a conductive material, such as ruthenium, to reduce the Schottky effects at the interface with the channel material.

## Claims

### Claim 1

A semiconductor device, comprising:
a transistor comprising:
a channel comprising oxide semiconductor material;
a first contact vertically overlying the channel and comprising one or more of ruthenium and ruthenium oxide;
a second contact vertically underlying the channel and comprising one or more of ruthenium and ruthenium oxide;
a gate electrode horizontally neighboring the channel in a first direction and confined within vertical boundaries of the channel; and
a gate dielectric material horizontally extending from and between the channel and the gate electrode in the first direction and vertically extending from and between the first contact and the second contact, the gate dielectric material substantially horizontally overlapping the first contact and the second contact in the first direction;
a first conductive line vertically overlying and in direct physical contact with the first contact, the first conductive line comprising one or more of titanium nitride and tungsten; and
a second conductive line vertically underlying and in direct physical contact with the second contact, the second conductive line comprising one or more of titanium nitride and tungsten.

### Claim 2 (depends on 1)

The semiconductor device of claim 1, wherein the oxide semiconductor material comprises In2O3.

### Claim 3 (depends on 2)

The semiconductor device of claim 2, wherein one or more of the first conductive line and the second conductive line individually comprises a combination of titanium nitride and tungsten.

### Claim 4 (depends on 2)

The semiconductor device of claim 2, wherein one or more of the first conductive line and the second conductive line individually comprise tungsten.

### Claim 5 (depends on 2)

The semiconductor device of claim 2, wherein one or more of the first conductive line and the second conductive line individually comprises a combination of titanium nitride, tungsten, and additional conductive material.

### Claim 6 (depends on 1)

The semiconductor device of claim 1, wherein the first conductive line has a different material composition than the second conductive line.

### Claim 7 (depends on 1)

The semiconductor device of claim 1, wherein the first contact extends across entireties of upper ends of the channel and the gate dielectric material.

### Claim 8 (depends on 7)

The semiconductor device of claim 7, wherein the second contact extends across entireties of lower ends of the channel and the gate dielectric material.

### Claim 9 (depends on 1)

The semiconductor device of claim 1, wherein an inner sider surface of the gate electrode is substantially coplanar with outer side surfaces of the first contact and the second contact.

### Claim 10 (depends on 1)

The semiconductor device of claim 1, wherein an inner sider surface of the gate electrode is within a horizontal area of one or more of the first contact and the second contact.

### Claim 11 (depends on 1)

The semiconductor device of claim 1, wherein:
the first contact is embedded within the first conductive line; and
the second contact is embedded within the second conductive line.

### Claim 12

A semiconductor device, comprising:
a vertically oriented transistor comprising:
a drain contact comprising ruthenium;
a source contact comprising additional ruthenium;
a channel region vertically interposed between drain contact and the source contact and comprising oxide semiconductor material;
a gate electrode horizontally neighboring the channel region and vertically interposed between drain contact and the source contact; and
a gate dielectric material horizontally interposed between the channel region and the gate electrode and vertically interposed between drain contact and the source contact, the gate dielectric material substantially confined within horizontal areas of the drain contact and the source contact;
a data line in electrical communication with the drain contact of the vertically oriented transistor;
a drain line comprising conductive material including one or more of tungsten and titanium nitride; and
a source line in electrical communication with the source contact of the vertically oriented transistor, the source line comprising additional conductive material.

### Claim 13 (depends on 12)

The semiconductor device of claim 12, wherein the channel region comprises In2O3 vertically adjacent the drain contact.

### Claim 14 (depends on 13)

The semiconductor device of claim 13, wherein the conductive material of the drain line comprises the titanium nitride, the titanium nitride in physical contact with the ruthenium of the drain contact.

### Claim 15 (depends on 13)

The semiconductor device of claim 13, wherein the conductive material of the drain line comprises the tungsten, the tungsten in physical contact with the ruthenium of the drain contact.

### Claim 16 (depends on 13)

The semiconductor device of claim 13, wherein the conductive material of the drain line comprises a layer of the titanium nitride and an additional layer of the tungsten.

### Claim 17 (depends on 13)

The semiconductor device of claim 13, wherein the additional conductive material of the source line comprises one or more of additional tungsten and additional titanium nitride.

### Claim 18

A semiconductor device, comprising:
a transistor comprising:
a channel comprising oxide semiconductor material;
a drain contact vertically adjacent a first end of the channel and comprising ruthenium;
a source contact vertically adjacent a second end of the channel and comprising additional ruthenium;
a gate electrode horizontally neighboring the channel and vertically interposed between drain contact and the source contact; and
a gate dielectric material horizontally extending from and between the channel and the gate electrode, the gate dielectric material substantially confined within a horizontal area of each of the drain contact and source contact and vertically extending from a vertical boundary of the drain contact to a vertical boundary of the source contact;
a data line in physical contact with the ruthenium of the drain contact of the transistor, the data line comprising one or more of tungsten and titanium nitride; and
a source line in physical contact with the additional ruthenium of the source contact of the transistor.

### Claim 19 (depends on 18)

The semiconductor device of claim 18, wherein:
the channel of the transistor comprises In2O3; and
the data line comprises a combination of the tungsten and the titanium nitride.

### Claim 20 (depends on 19)

The semiconductor device of claim 19, further comprising ruthenium oxide at an interface of the In2O3 of the channel and the ruthenium of the drain contact.