# US 12,112,975 B2 · Mechanism for finFET well doping

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- Number: US 12,112,975 B2
- Document ID: US12112975B2
- Status: Granted
- Kind: B2
- Application number: 18/346,622
- Filed: 2023-07-03
- Published: 2023-10-26
- Granted: 2024-10-08
- Earliest claimed: 2013-12-20
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Company, Ltd.
- Inventors: Chun Hsiung Tsai; Yan-Ting Lin; Clement Hsingjen Wann
- Web page: https://patentgrep.com/patent/US12112975B2

## CPC

- H10W 10/014: {using trench refilling with dielectric materials, e.g. shallow trench isolations}
- H10D 30/024: {of fin field-effect transistors [FinFET]}
- H10D 30/6211: {having fin-shaped semiconductor bodies integral with the bulk semiconductor substrates}
- H10D 62/115: {Dielectric isolations, e.g. air gaps}
- H10D 62/60: Impurity distributions or concentrations
- H10D 84/0156: {Manufacturing their doped wells}
- H10D 84/0193: {the components including FinFETs}
- H10D 84/853: {comprising FinFETs}
- H10D 86/215: {comprising FinFETs}
- H10P 14/6334: {using decomposition or reaction of gaseous or vapour phase compounds, i.e. chemical vapour deposition (deposition by physical ablation of a target H10P14/6329)}
- H10P 14/6336: {in the presence of a plasma [PECVD]}
- H10P 14/6516: {of treatments performed after formation of the materials}
- H10P 14/6518: {by introduction of substances into an already-existing insulating layer}
- H10P 14/6519: {the substance being oxygen}
- H10P 14/6522: {introduced into a nitride material, e.g. changing SiN to SiON}
- H10P 14/6529: {by exposure to a gas or vapour}
- H10P 14/6687: {the compound comprising silicon and nitrogen}
- H10P 14/6689: {the compound being a silazane}
- H10P 14/69215: {the material being a silicon oxide, e.g. SiO2}
- H10P 30/40: into insulating materials
- H10P 95/90: Thermal treatments, e.g. annealing or sintering
- H10W 10/0148: {comprising introducing impurities in side walls or bottom walls of trenches, e.g. for forming channel stoppers}
- H10W 10/17: formed using trench refilling with dielectric materials, e.g. shallow trench isolations
- H10D 30/0241: {doping of vertical sidewalls, e.g. using tilted or multi-angled implants}
- H10D 30/751: {having composition variations in the channel regions}
- H10D 62/151: {of IGFETs (of IGFETs having LDD or DDD structure H10D30/601; of thin film transistors H10D30/6713)}
- H10D 64/017: {using dummy gates in processes wherein at least parts of the final gates are self-aligned to the dummy gates, i.e. replacement gate processes}
- H10D 84/0158: {the components including FinFETs}
- H10D 84/038: {using silicon technology, e.g. SiGe}
- H10D 84/834: {comprising FinFETs}
- H10P 14/65: {characterised by treatments performed before or after the formation of the materials}
- H10P 14/6927: {the material being a silicon oxynitride, e.g. SiON or SiON:H}
- H10P 30/204: {into Group IV semiconductors}
- H10P 30/21: {of electrically active species}
- H10P 30/28: characterised by an annealing step, e.g. for activation of dopants
- H10P 32/141: {the applied layer comprising oxides only}
- H10P 32/171: {being group IV material}
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

The embodiments of mechanisms for doping wells of finFET devices described in this disclosure utilize depositing doped films to dope well regions. The mechanisms enable maintaining low dopant concentration in the channel regions next to the doped well regions. As a result, transistor performance can be greatly improved. The mechanisms involve depositing doped films prior to forming isolation structures for transistors. The dopants in the doped films are used to dope the well regions near fins. The isolation structures are filled with a flowable dielectric material, which is converted to silicon oxide with the usage of microwave anneal. The microwave anneal enables conversion of the flowable dielectric material to silicon oxide without causing dopant diffusion. Additional well implants may be performed to form deep wells. Microwave anneal(s) may be used to anneal defects in the substrate and fins.

## Claims

### Claim 1

A device comprising:
a first fin extending from a major surface of a substrate, the first fin having a p-type well region and having a p-type channel region over the p-type well region, the p-type well region and a first region of the substrate comprising p-type dopants at a first concentration, the p-type channel region comprising p-type dopants at a second concentration, the second concentration being less than the first concentration, the first region of the substrate extending below the major surface of the substrate to a first depth;
a second fin extending from the major surface of the substrate, the second fin having an n-type well region and having an n-type channel region over the n-type well region, the n-type well region and a second region of the substrate comprising n-type dopants at a third concentration, the n-type channel region comprising n-type dopants at a fourth concentration, the fourth concentration being less than the third concentration, the second region of the substrate extending below the major surface of the substrate to a second depth, the first depth being different from the second depth; and
an isolation structure surrounding the p-type well region and the n-type well region, the p-type channel region and the n-type channel region protruding above a top surface of the isolation structure.

### Claim 2 (depends on 1)

The device of claim 1, wherein the first depth is greater than the second depth.

### Claim 3 (depends on 1)

The device of claim 1 further comprising:
a gate structure over the p-type channel region and the isolation structure; and
a n-type source/drain region adjacent the gate structure.

### Claim 4 (depends on 1)

The device of claim 1 further comprising:
a gate structure over the n-type channel region and the isolation structure; and
a p-type source/drain region adjacent the gate structure.

### Claim 5 (depends on 1)

The device of claim 1, wherein the first concentration and the third concentration are in a range from about 1E18 atoms/cm3 to about 6E18 atoms/cm3.

### Claim 6 (depends on 1)

The device of claim 1, wherein the second concentration and the fourth concentration are in a range from about 5E16 atoms/cm3 to about 5E17 atoms/cm3.

### Claim 7 (depends on 1)

The device of claim 1 further comprising:
a p-type dopant layer between the isolation structure and the p-type well region; and
a n-type dopant layer between the isolation structure and the n-type well region.

### Claim 8 (depends on 7)

The device of claim 7, wherein the p-type dopant layer comprises p-type dopants at a fifth concentration, the n-type dopant layer comprises n-type dopants at a sixth concentration, and the fifth concentration and the sixth concentration are in a range from about 1E19 atoms/cm3 to about 5E20 atoms/cm3.

### Claim 9 (depends on 1)

The device of claim 1, wherein the isolation structure comprises a SiOH+SIO network.

### Claim 10 (depends on 1)

The device of claim 1, wherein the first depth is in a range from about 80 nm to about 200 nm, and wherein the second depth is in a range from about 80 nm to about 150 nm.

### Claim 11

A device comprising:
a first fin extending from a first region of a substrate, the first fin having a first well region and having a first channel region over the first well region, the first well region and the first region of the substrate comprising first majority carriers at a first concentration, the first channel region comprising the first majority carriers at a second concentration, the second concentration being less than the first concentration, the first region of the substrate extending below a top surface of the substrate to a first depth; and
a second fin extending from a second region of the substrate, the second fin having a second well region and having a second channel region over the second well region, the second well region and the second region of the substrate comprising second majority carriers at a third concentration, the second channel region comprising the second majority carriers at a fourth concentration, the fourth concentration being less than the third concentration, the second region of the substrate extending below the top surface of the substrate to a second depth, the first depth being different from the second depth.

### Claim 12 (depends on 11)

The device of claim 11, further comprising:
an isolation structure on the top surface of the substrate, wherein a first portion of the first channel region and a second portion of the second channel region are disposed in the isolation structure.

### Claim 13 (depends on 11)

The device of claim 11, wherein the first majority carriers are holes, the second majority carriers are electrons, and the first depth is greater than the second depth.

### Claim 14 (depends on 11)

The device of claim 11 further comprising:
an isolation structure on the top surface of the substrate;
a first dopant layer between the isolation structure and the first well region of the first fin, the first dopant layer comprising a first dopant for the first majority carriers; and
a second dopant layer between the isolation structure and the second well region of the second fin, the second dopant layer comprising a second dopant for the second majority carriers.

### Claim 15 (depends on 11)

The device of claim 11, wherein the first concentration and the third concentration are in a range from about 1E18 atoms/cm3 to about 6E18 atoms/cm3.

### Claim 16 (depends on 11)

The device of claim 11, wherein the second concentration and the fourth concentration are in a range from about 5E16 atoms/cm3 to about 5E17 atoms/cm3.

### Claim 17

A device comprising:
first fins extending from a substrate;
a first well region in the first fins and the substrate, the first well region having a first depth below a surface of the substrate;
first channel regions in the first fins, the first channel regions having a lesser dopant concentration than the first well region;
second fins extending from the substrate;
a second well region in the second fins and the substrate, the second well region having a second depth below the surface of the substrate, the second depth being different from the first depth; and
second channel regions in the second fins, the second channel regions having a lesser dopant concentration than the second well region, the second channel regions and the first channel regions being oppositely doped.

### Claim 18 (depends on 17)

The device of claim 17 further comprising:
an isolation structure surrounding the first fins and the second fins, a top surface of the isolation structure disposed further from the surface of the substrate than a top surface of the first well region and a top surface of the second well region.

### Claim 19 (depends on 18)

The device of claim 18 further comprising:
a first layer between the isolation structure and the first fins, the first layer and the first well region comprising a first dopant; and
a second layer between the isolation structure and the second fins, the second layer and the second well region comprising a second dopant, the second dopant being different from the first dopant.

### Claim 20 (depends on 19)

The device of claim 19, wherein the first dopant is a p-type dopant, the second dopant is an n-type dopant, and the first depth is greater than the second depth.