# US 8,785,286 B2 · Techniques for FinFET doping

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- Number: US 8,785,286 B2
- Document ID: US8785286B2
- Status: Granted
- Kind: B2
- Application number: 12/702,803
- Filed: 2010-02-09
- Published: 2011-08-11
- Granted: 2014-07-22
- Earliest claimed: 2010-02-09
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Chun Hsiung Tsai; Chien-Tai Chan; Mao-Rong Yeh; Da-Wen Lin
- Inventors: Chun Hsiung Tsai; Chien-Tai Chan; Mao-Rong Yeh; Da-Wen Lin
- Web page: https://patentgrep.com/patent/US8785286B2

## CPC

- H10D 30/0241: {doping of vertical sidewalls, e.g. using tilted or multi-angled implants}
- H10P 30/204: {into Group IV semiconductors}
- H10P 30/214: {Recoil-implantation}
- H10P 30/221: {characterised by the angle between the ion beam and the mask}
- H10P 30/222: {characterised by the angle between the ion beam and the crystal planes or the main crystal surface (characterised by the angle between the ion beam and the mask H10P30/221)}
- H10P 32/1204: {from a plasma phase}
- H10P 32/1408: {from or through or into an external applied layer, e.g. photoresist or nitride layers}
- H10P 32/171: {being group IV material}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A method of forming an integrated circuit includes providing a semiconductor wafer including a semiconductor fin dispatched on a surface of the semiconductor wafer; forming a dopant-rich layer having an impurity on a top surface and sidewalls of the semiconductor fin, wherein the impurity is of n-type or p-type; performing a knock-on implantation to drive the impurity into the semiconductor fin; and removing the dopant-rich layer.

## Claims

### Claim 1

A method of forming an integrated circuit, the method comprising:
providing a semiconductor wafer comprising a semiconductor fin dispatched on a surface of the semiconductor wafer;
forming a dopant-rich layer comprising an impurity on a top surface and sidewalls of the semiconductor fin, wherein the dopant-rich layer is a substantially pure layer comprising substantially pure n-type or p-type impurity;
performing a knock-on implantation to drive the impurity into the semiconductor fin, wherein the knock-on implantation is performed using carbon, germanium, argon, or nitrogen to drive the impurity into the semiconductor fin; and
removing the dopant-rich layer substantially completely.

### Claim 2 (depends on 1)

The method of claim 1, wherein the dopant-rich layer is substantially free from elements other than the n-type or p-type impurity.

### Claim 3 (depends on 1)

The method of claim 1, wherein the knock-on implantation is a tilt implantation.

### Claim 4 (depends on 1)

The method of claim 1 further comprising, before the step of forming the dopant-rich layer, forming a gate dielectric and a gate electrode on the semiconductor fin.

### Claim 5 (depends on 1)

The method of claim 1, wherein the step of performing the knock-on implantation forms a lightly-doped source/drain (LDD) region of a fin field-effect transistor (FinFET) in the semiconductor fin.

### Claim 6 (depends on 1)

The method of claim 1 further comprising:
before the step of forming the dopant-rich layer, forming a photo resist covering a portion of the semiconductor wafer, wherein a portion of the semiconductor fin for forming the dopant rich layer thereon is not covered; and
after the step of performing the knock-on implantation, removing the photo resist.

### Claim 7 (depends on 1)

The method of claim 1, wherein the step of forming the dopant-rich layer comprises a plasma ion assisted deposition.

### Claim 8 (depends on 7)

The method of claim 7, wherein a DC bias power for performing the plasma ion assisted deposition is lower than about 1.5 kV.

### Claim 9 (depends on 7)

The method of claim 7, wherein during the plasma ion assisted deposition, no DC bias voltage is applied.

### Claim 10 (depends on 1)

The method of claim 1, wherein after the step of removing the dopant-rich layer, an entirety of the dopant-rich layer is removed.

### Claim 11

A method of forming an integrated circuit, the method comprising:
providing a semiconductor wafer comprising a semiconductor fin dispatched on a surface of the semiconductor wafer;
forming a dopant-rich layer comprising an impurity on a top surface and sidewalls of the semiconductor fin, wherein the impurity is of n-type or p-type;
performing a knock-on implantation to drive the impurity into the semiconductor fin, wherein the knock-on implantation forms a lightly-doped source/drain (LDD) region of a fin field-effect transistor (FinFET) in the semiconductor fin, wherein the knock-on implantation is performed using carbon, germanium, argon, or nitrogen to drive the impurity into the semiconductor fin; and
removing the dopant-rich layer substantially completely.

### Claim 12 (depends on 11)

The method of claim 11, wherein the dopant-rich layer comprises a substantially pure n-type or p-type impurity.

### Claim 13 (depends on 11)

The method of claim 11 further comprising, before the step of forming the dopant-rich layer, forming a gate dielectric and a gate electrode on the semiconductor fin.

### Claim 14 (depends on 11)

The method of claim 11 further comprising:
before the step of forming the dopant-rich layer, forming a photo resist covering a portion of the semiconductor wafer, wherein a portion of the semiconductor fin for forming the dopant rich layer thereon is not covered; and
after the step of performing the knock-on implantation, removing the photo resist.

### Claim 15 (depends on 11)

The method of claim 11, wherein the step of forming the dopant-rich layer comprises a plasma ion assisted deposition.

### Claim 16

A method of forming an integrated circuit, the method comprising:
providing a semiconductor wafer comprising a semiconductor fin dispatched on a surface of the semiconductor wafer;
foaming a dopant-rich layer comprising an impurity on a top surface and sidewalls of the semiconductor fin, wherein the impurity is of n-type or p-type;
performing a knock-on implantation to drive the impurity into the semiconductor fin, wherein the knock-on implantation is performed using carbon, germanium, argon, or nitrogen to drive the impurity into the semiconductor fin; and
removing the dopant-rich layer substantially completely.

### Claim 17 (depends on 16)

The method of claim 16, wherein the dopant-rich layer is a substantially pure n-type or p-type impurity layer, with substantially no other elements other than the n-type or p-type impurity therein.

### Claim 18 (depends on 16)

The method of claim 16, wherein the step of forming the dopant-rich layer comprises a plasma ion assisted deposition.