# US 10,312,237 B2 · Vertical transport transistors with equal gate stack thicknesses

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- Number: US 10,312,237 B2
- Document ID: US10312237B2
- Status: Granted
- Kind: B2
- Application number: 16/058,173
- Filed: 2018-08-08
- Published: 2018-12-06
- Granted: 2019-06-04
- Earliest claimed: 2017-05-01
- Assignees: International Business Machines Corporation
- Applicants: International Business Machines Corporation
- Inventors: Ruqiang Bao; Zhenxing Bi; Choonghyun Lee; Zheng Xu
- Web page: https://patentgrep.com/patent/US10312237B2

## CPC

- H10D 84/85: Complementary IGFETs, e.g. CMOS
- H10B 63/34: {of the vertical channel field-effect transistor type}
- H10D 30/025: {of vertical IGFETs (of VDMOS H10D30/0291; of vertical TFTs H10D30/0318)}
- H10D 30/0291: {of vertical DMOS [VDMOS] FETs}
- H10D 30/0293: {using formation of insulating sidewall spacers}
- H10D 30/0297: {using recessing of the gate electrodes, e.g. to form trench gate electrodes}
- H10D 30/63: Vertical IGFETs (H10D30/66 {, H10D30/6728, H10D30/689, H10D30/693} take precedence)
- H10D 30/66: Vertical DMOS [VDMOS] FETs
- H10D 30/6728: {Vertical TFTs}
- H10D 62/151: {of IGFETs (of IGFETs having LDD or DDD structure H10D30/601; of thin film transistors H10D30/6713)}
- H10D 64/015: {removing at least parts of gate spacers, e.g. disposable spacers}
- H10D 64/667: {the conductor comprising a layer of alloy material, compound material or organic material contacting the insulator, e.g. TiN workfunction layers (having lateral variation H10D64/671)}
- H10D 64/669: {the conductor further comprising additional layers of alloy material, compound material or organic material, e.g. TaN/TiAlN}
- H10D 84/0121: {the complementary BJTs being vertical BJTs}
- H10D 84/016: {the components including vertical IGFETs}
- H10D 84/0177: {the gate conductors having different materials or different implants}
- H10D 84/0195: {the components including vertical IGFETs}
- H10D 84/038: {using silicon technology, e.g. SiGe}
- H10D 84/141: {VDMOS having built-in components}
- H10D 84/613: {Combinations of vertical BJTs and one or more of diodes, resistors or capacitors}
- H10D 84/615: {Combinations of vertical BJTs and one or more of resistors or capacitors}
- H10D 84/617: {Combinations of vertical BJTs and only diodes}
- H10D 84/83135: {the IGFETs characterised by having different gate conductor materials or different gate conductor implants}
- H10D 84/837: {comprising vertical IGFETs}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10B: ELECTRONIC MEMORY DEVICES

## Abstract

Integrated chips include a first semiconductor device and a second semiconductor device. The first semiconductor device includes a semiconductor channel, a first-type work function layer formed from a first material on the semiconductor channel, and a second-type work function layer formed from a second material on the first-type work function later layer. The second semiconductor device includes a semiconductor channel, a second-type work function layer formed the second material on the semiconductor channel, and a thickness matching layer formed on the second-type work function layer of the second semiconductor device, the thickness matching layer having a thickness roughly equal to a thickness of the first-type work function layer.

## Claims

### Claim 1

An integrated chip, comprising:
a first semiconductor device, the first semiconductor device comprising:
a semiconductor channel;
a first-type work function layer formed from a first material on the semiconductor channel; and
a second-type work function layer formed from a second material on the first-type work function later layer; and
a second semiconductor device, the second semiconductor device comprising:
a semiconductor channel;
a second-type work function layer formed from the second material on the semiconductor channel; and
a thickness matching layer formed on the second-type work function layer of the second semiconductor device, the thickness matching layer having a thickness roughly equal to a thickness of the first-type work function layer.

### Claim 2 (depends on 1)

The integrated chip of claim 1, further comprising an inter-device connection that connects the first semiconductor device and the second semiconductor device and comprises portions of the first-type work function layer, the second-type work function layer, and the thickness matching layer.

### Claim 3 (depends on 1)

The integrated chip of claim 1, wherein the first semiconductor device is an n-type transistor and wherein the second semiconductor device is a p-type transistor.

### Claim 4 (depends on 3)

The integrated chip of claim 3, wherein the first-type work function layer comprises an n-type titanium nitride layer, a titanium aluminum carbon layer, and a second titanium nitride layer and wherein the second-type work function layer comprises a p-type titanium nitride layer.

### Claim 5 (depends on 3)

The integrated chip of claim 3, wherein the first semiconductor device further comprises a scavenging layer on the second-type work function layer and wherein the second semiconductor device further comprises a scavenging layer between the second-type work function layer and the thickness matching layer.

### Claim 6 (depends on 5)

The integrated chip of claim 5, wherein the thickness matching layer comprises a material selected from the group consisting of titanium nitride, cobalt, and tungsten.

### Claim 7 (depends on 1)

The integrated chip of claim 1, wherein the first semiconductor device is a p-type transistor and wherein the second semiconductor device is an n-type transistor.

### Claim 8 (depends on 7)

The integrated chip of claim 7, wherein the first-type work function layer comprises a p-type titanium nitride layer and wherein the second-type work function layer comprises an n-type titanium nitride layer and a titanium aluminum carbon layer.

### Claim 9 (depends on 7)

The integrated chip of claim 7, wherein the thickness matching layer comprises a material selected from the group consisting of titanium nitride, cobalt, and tungsten.

### Claim 10 (depends on 7)

The integrated chip of claim 7, wherein the second-type work function layer further comprises a second titanium nitride layer.

### Claim 11 (depends on 1)

The integrated chip of claim 1, wherein the first semiconductor device further comprises a scavenging layer on the second-type work function layer and wherein the second semiconductor device further comprises a scavenging layer between the second-type work function layer and the thickness matching layer.

### Claim 12

An integrated chip, comprising:
a first semiconductor device, the first semiconductor device comprising:
a semiconductor channel;
a first-type work function layer formed on the semiconductor channel; and
a second-type work function layer formed on the first-type work function layer;
a second semiconductor device, the second semiconductor device comprising:
a semiconductor channel;
a second-type work function layer formed on the semiconductor channel; and
a thickness matching layer formed on the second-type work function layer, the thickness matching layer having a thickness roughly equal to a thickness of the first-type work function layer; and
an inter-device connection that connects the first semiconductor device and the second semiconductor device, comprising portions of the first-type work function layer, the second-type work function layer, and the thickness matching layer.

### Claim 13 (depends on 12)

The integrated chip of claim 12, wherein the first semiconductor device further comprises a scavenging layer on the second-type work function layer and wherein the second semiconductor device further comprises a scavenging layer between the second-type work function layer and the thickness matching layer.

### Claim 14 (depends on 13)

The integrated chip of claim 13, wherein the thickness matching layer comprises a material selected from the group consisting of titanium nitride, cobalt, and tungsten.

### Claim 15

An integrated chip, comprising:
a first semiconductor device, comprising:
a semiconductor channel;
a first-type work function layer formed on the semiconductor channel;
a second-type work function layer formed on the first-type work function layer; and
a scavenging layer on the second-type work function layer; and
a second semiconductor device, comprising:
a semiconductor channel;
a second-type work function layer formed on the semiconductor channel;
a scavenging layer on the second-type work function layer; and
a thickness matching layer formed on the scavenging layer, the thickness matching layer having a thickness roughly equal to a thickness of the first-type work function layer.

### Claim 16 (depends on 15)

The integrated chip of claim 15, further comprising an inter-device connection that connects the n-type transistor and the p-type transistor, said inter-device connection comprising portions of the first-type work function layer, the second-type work function layer, and the thickness matching layer.

### Claim 17 (depends on 15)

The integrated chip of claim 15, wherein the first semiconductor device is an n-type transistor and wherein the second semiconductor device is a p-type transistor.