# US 9,520,498 B2 · FinFET structure and method for fabricating the same

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- Number: US 9,520,498 B2
- Document ID: US9520498B2
- Status: Granted
- Kind: B2
- Application number: 14/216,535
- Filed: 2014-03-17
- Published: 2015-09-17
- Granted: 2016-12-13
- Earliest claimed: 2014-03-17
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Company, Ltd.
- Inventors: Kuo-Cheng Ching; Guan-Lin Chen; Chao Hsiung Wang; Chi-Wen Liu
- Web page: https://patentgrep.com/patent/US9520498B2

## CPC

- H10D 30/024: {of fin field-effect transistors [FinFET]}
- H10D 30/62: Fin field-effect transistors [FinFET]
- H10P 14/24: using chemical vapour deposition [CVD]
- H10P 14/3408: {Silicon carbide}
- H10P 14/3411: {Silicon, silicon germanium or germanium}
- H10P 14/6308: {of Group IV semiconductors}
- H10P 52/402: {of semiconductor materials}
- H10P 14/3444: {P-type}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A device comprises a substrate comprising silicon, a fin structure comprising a lower portion formed of silicon and enclosed by an isolation region, a middle portion formed of silicon-germanium-carbon, wherein the middle portion is enclosed by an oxide layer, an upper portion formed of silicon, wherein the upper portion comprises a channel and a silicon-carbon layer formed between the middle portion and the upper portion, a first source/drain region comprising a first silicon-phosphorus region and a first silicon-carbon layer formed underlying the first silicon-phosphorus region and a second source/drain region comprising a second silicon-phosphorus region and a second silicon-carbon layer formed underlying the second silicon-phosphorus region.

## Claims

### Claim 1

An apparatus comprising:
a substrate formed of a first semiconductor material;
a fin structure protruding over the substrate, wherein the fin structure comprises:
a lower portion formed of the first semiconductor material;
a middle portion formed of a second semiconductor material;
an upper portion formed of the first semiconductor material, wherein the upper portion comprises a channel connected between a first source/drain region and a second source/drain region; and
a first carbon doped layer formed between the middle portion and the upper portion;
a second carbon doped layer formed underlying the first source/drain region; and
a third carbon doped layer formed underlying the second source/drain region.

### Claim 2 (depends on 1)

The apparatus of claim 1, further comprising:
a gate region wrapping the channel of the fin structure.

### Claim 3 (depends on 1)

The apparatus of claim 1, wherein:
the first semiconductor material is silicon; and
the second semiconductor material is silicon-germanium-carbon (SiGeC).

### Claim 4 (depends on 1)

The apparatus of claim 1, wherein:
the first carbon doped layer is formed of silicon-carbon (SiC);
the second carbon doped layer is formed of SiC; and
the third carbon doped layer is formed of SiC.

### Claim 5 (depends on 1)

The apparatus of claim 1, wherein:
the second carbon doped layer is formed of silicon-carbon-phosphorus (SiCP); and
the third carbon doped layer is formed of SiCP.

### Claim 6 (depends on 1)

The apparatus of claim 1, wherein:
the first source/drain region is formed of silicon-phosphorus (SiP); and
the second source/drain region is formed of SiP.

### Claim 7 (depends on 1)

The apparatus of claim 1, wherein:
the middle portion of the fin structure comprises an oxide outer layer, and wherein the oxide outer layer is formed of SiGeOx, and wherein x is oxygen composition in atomic percentage.

### Claim 8

A device comprising:
a substrate comprising silicon;
a fin structure protruding over the substrate, wherein the fin structure comprises:
a lower portion formed of silicon and enclosed by an isolation region;
a middle portion formed of silicon-germanium-carbon, wherein the middle portion is enclosed by an oxide layer;
an upper portion formed of silicon, wherein the upper portion comprises a channel; and
a silicon-carbon layer formed between the middle portion and the upper portion;
a first source/drain region comprising a first silicon-phosphorus region and a first silicon-carbon layer formed underlying the first silicon-phosphorus region; and
a second source/drain region comprising a second silicon-phosphorus region and a second silicon-carbon layer formed underlying the second silicon-phosphorus region.

### Claim 9 (depends on 8)

The device of claim 8, wherein:
the first source/drain region is of a thickness in a range from about 30 nm to about 50 nm; and
the second source/drain region is of a thickness in a range from about 30 nm to about 50 nm.

### Claim 10 (depends on 8)

The device of claim 8, wherein:
the oxide layer comprises SiGeOx, and wherein x is oxygen composition in atomic percentage.

### Claim 11 (depends on 8)

The device of claim 8, wherein:
the silicon-carbon layer is of a thickness in a range from about 5 nm to about 15 nm.

### Claim 12 (depends on 11)

The device of claim 11, wherein:
a carbon concentration of the silicon-carbon layer is from about 0.5% to about 2% in atomic percentage.

### Claim 13 (depends on 8)

The device of claim 8, wherein:
a germanium concentration of the middle portion is from about 20% to about 45%; and
a carbon concentration of the middle portion is from about 0.5% to about 2%.

### Claim 14 (depends on 8)

The device of claim 8, wherein:
the silicon-carbon layer further comprises phosphorus.

### Claim 15 (depends on 14)

The device of claim 14, wherein:
a phosphorus concentration is in a range from about 1E20/cm3 to about 5E20/cm3.

### Claim 16

A device comprising:
a fin structure over a silicon substrate, wherein the fin structure comprises:
a lower portion formed of silicon;
a middle portion formed of silicon-germanium-carbon;
an upper portion formed of silicon; and
a silicon-carbon layer formed between the middle portion and the upper portion;
a first source/drain region comprising a first silicon-phosphorus region and a first silicon-carbon layer formed underlying the first silicon-phosphorus region; and
a second source/drain region comprising a second silicon-phosphorus region and a second silicon-carbon layer formed underlying the second silicon-phosphorus region.

### Claim 17 (depends on 16)

The device of claim 16, wherein:
a first gap is between a bottom surface of the first silicon-carbon layer and a top surface of the silicon-carbon layer; and
a second gap is between a bottom surface of the second silicon-carbon layer and the top surface of the silicon-carbon layer.

### Claim 18 (depends on 17)

The device of claim 17, wherein:
a height of the first gap is equal to a height of the second gap.

### Claim 19 (depends on 16)

The device of claim 16, wherein:
the lower portion is enclosed by an isolation region.

### Claim 20 (depends on 16)

The device of claim 16, wherein:
the upper portion comprises a channel connected between the first source/drain region and the second source/drain region.