# US 2022/0285358 A1 · Semiconductor device and fabrication method of the same

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- Number: US 2022/0285358 A1
- Document ID: US20220285358A1
- Status: Published application
- Kind: A1
- Application number: 17/478,147
- Filed: 2021-09-17
- Published: 2022-09-08
- Earliest claimed: 2021-03-05
- Assignees: SK hynix Inc.
- Applicants: SK hynix Inc.
- Inventors: Seung Mi LEE
- Web page: https://patentgrep.com/patent/US20220285358A1

## CPC

- H10B 12/315: {with the capacitor higher than a bit line}
- H10B 12/0335: {Making a connection between the transistor and the capacitor, e.g. plug}
- H10B 12/34: {the transistor being at least partially in a trench in the substrate}
- H10B 12/482: {Bit lines}
- H10W 10/021: {of air gaps}
- H10W 10/20: Air gaps
- H10B: ELECTRONIC MEMORY DEVICES
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

A semiconductor device includes: a bit line structure formed over a substrate; a storage node contact plug spaced apart from the bit line structure; and a nitride spacer positioned between the bit line structure and the storage node contact plug, wherein the nitride spacer has a higher silicon content in a portion adjacent to the storage node contact plug than in a portion adjacent to the bit line structure,

## Claims

### Claim 1

A semiconductor device, comprising:
a bit line structure formed over a substrate;
a storage node contact plug spaced apart from the bit line structure; and
a nitride spacer positioned between the bit line structure and the storage node contact plug,
wherein the nitride spacer has a higher silicon content in a portion adjacent to the storage node contact plug than in a portion adjacent to the bit line structure.

### Claim 2 (depends on 1)

The semiconductor device of claim 1, wherein the nitride spacer includes a stacked structure of a first nitride spacer which is in contact with the bit line structure and a second nitride spacer which has a higher silicon content than the first nitride spacer.

### Claim 3 (depends on 2)

The semiconductor device of claim 2, wherein the second nitride spacer is spaced apart from the bit line structure by the first nitride spacer.

### Claim 4 (depends on 2)

The semiconductor device of claim 2, wherein the second nitride spacer has a silicon content of approximately 45 at % to 55 at %.

### Claim 5 (depends on 1)

The semiconductor device of claim 1, wherein the nitride spacer is a single layer whose silicon content in a portion closest to the bit line structure is the same as a silicon content of silicon nitride having a stoichiometric composition, and whose silicon content gradually increases going toward the storage node contact plug.

### Claim 6 (depends on 5)

The semiconductor device of claim 5, wherein the nitride spacer has a silicon content of approximately 45 at % to 55 at % at a portion closest to the storage node contact plug.

### Claim 7 (depends on 1)

The semiconductor device of claim 1, further comprising:
first and second spacers between the bit line structure and the nitride spacer.

### Claim 8 (depends on 7)

The semiconductor device of claim 7, wherein the first spacer contains silicon nitride, and the second spacer contains silicon oxide.

### Claim 9

A semiconductor device, comprising:
a bit line structure formed over the substrate;
a storage node contact plug spaced apart from the bit line structure; and
an air gap spacer positioned between the bit line structure and the storage node contact plug, and a nitride spacer over the air gap spacer,
wherein the nitride spacer has the lowest silicon content in a central portion, and has a higher silicon content in a portion adjacent to the storage node contact plug than in the central portion.

### Claim 10 (depends on 9)

The semiconductor device of claim 9, wherein the nitride spacer includes a stacked structure of first to third nitride spacers, and the first nitride spacer is in contact with the air gap spacer.

### Claim 11 (depends on 10)

The semiconductor device of claim 10, wherein the first and third nitride spacers have a higher silicon content than the second nitride spacers.

### Claim 12 (depends on 10)

The semiconductor device of claim 10, wherein the first and third nitride spacers have a silicon content of approximately 45 at % to 55 at %.

### Claim 13 (depends on 9)

The semiconductor device of claim 9, wherein the nitride spacer is a single layer that has the lowest silicon content in the central portion and has the silicon content gradually increasing going toward the air gap spacer and the storage node contact plug.

### Claim 14 (depends on 13)

The semiconductor device of claim 13, wherein the nitride spacer has a silicon content of approximately 45 at % to 55 at % in a portion closest to the air gap spacer and the storage node contact plug.