# US 7,612,420 B2 · Method for doping a fin-based semiconductor device

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- Number: US 7,612,420 B2
- Document ID: US7612420B2
- Status: Granted
- Kind: B2
- Application number: 11/843,569
- Filed: 2007-08-22
- Published: 2008-02-28
- Granted: 2009-11-03
- Earliest claimed: 2006-08-23
- Assignees: Imec; STMicroelectronics (Croelles2) SAS
- Inventors: Damien Lenoble
- Web page: https://patentgrep.com/patent/US7612420B2

## CPC

- 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)}
- H10D 30/0241: {doping of vertical sidewalls, e.g. using tilted or multi-angled implants}
- H10D 30/62: Fin field-effect transistors [FinFET]
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

A method for doping a fin-based semiconductor device is disclosed. In one aspect, the method comprises patterning at least one fin, each fin comprising a top surface and a left sidewall surface and a right sidewall surface. The method further comprises providing a first target surface being the right sidewall of a first block of material. The method further comprises scanning a first primary ion beam impinging on the first target surface with an incident angle α different from zero degrees and thereby inducing a first secondary ion beam, and doping at least the left sidewall surface and possibly the top surface of the fin opposite to the first target surface with the first secondary ion beam.

## Claims

### Claim 1

A method of doping a fin-based semiconductor device comprising:
providing at least one fin, the fin comprising a top surface and a first sidewall surface and a second sidewall surface;
providing a first target surface being the sidewall of a first block of material facing the first sidewall surface of the fin,
scanning a first primary ion beam impinging on the first target surface with a first incident angle different from zero degrees and thereby inducing a first secondary ion beam, doping at least the first sidewall surface with the first secondary ion beam.

### Claim 2 (depends on 1)

The method according to claim 1, further comprising:
providing a second target surface being the sidewall of a second block of material facing the second sidewall of the fin, the second block of material having defined height, width and length such that the top surface of the fin is substantially shadowed from the first primary beam.

### Claim 3 (depends on 2)

The method according to claim 2, further comprising:
scanning a second primary ion beam impinging on the second target surface with a second incident angle different from zero degrees, thereby inducing a second secondary ion beam wherein the first block of material having a height, width and length such that the top surface of the fin is substantially shadowed from the second primary beam, and thereby
doping the second sidewall surface of the fin with the second secondary ion beam.

### Claim 4 (depends on 2)

The method according to claim 2, wherein the first target surface is located at a distance approximately in the range of 5 nm to 50 nm to the first sidewall surface of the fin and wherein the second target surface is located at a distance approximately in the range of 5 nm to 50 nm to the second sidewall surface of the fin.

### Claim 5 (depends on 2)

The method according to claim 2, wherein the first and second incident angles are selected such that the primary ion beams do not impinge on the top surface of the fin.

### Claim 6 (depends on 5)

The method according to claim 5, wherein the incident angles are approximately within the range of about 10 degrees to about 80 degrees with respect to the normal of the top surface of the fin.

### Claim 7 (depends on 6)

The method according to claim 6, wherein the incident angles are around 45 degrees with respect to the normal of the top surface of the fin.

### Claim 8 (depends on 1)

The method according to claim 1, wherein the incident angle is determined by the height of the block of material by:
Tan(90−α)=(BH−H)/(W+TD),
wherein BH=the height of the block of material, H=the height of the fin, W=the width of the fin and TD=the distance between the fin and the target surface.

### Claim 9 (depends on 2)

The method according to claim 2, wherein the material of the block of material is doped or undoped.

### Claim 10 (depends on 9)

The method according to claim 9, wherein ions of the primary ion beam impinging on the undoped block of material comprises doped ions.

### Claim 11 (depends on 10)

The method according to claim 10, wherein the secondary ion beam comprises backscattered doped ions.

### Claim 12 (depends on 9)

The method according to claim 9, wherein the secondary ion beam comprising sputtered doped ions.

### Claim 13 (depends on 1)

The method according to claim 1, wherein the providing of at least one fin further comprises providing a sequence or an array of fins comprising at least a first fin located at a fin pitch from a second fin.

### Claim 14 (depends on 13)

The method according to claim 13, wherein the first block of material is positioned in between the first fin and the second fin.

### Claim 15 (depends on 13)

The method according to claim 13, wherein the first block of material is positioned over the second fin.

### Claim 16 (depends on 1)

A fin-based semiconductor device obtainable by a process comprising the method according to claim 1.

### Claim 17

A method of doping a fin-based semiconductor device comprising:
providing at least one fin, the fin comprising a top surface and a first sidewall surface and a second sidewall surface;
providing a block of material with a sidewall facing the first sidewall surface of the fin, the sidewall of the block of material being a target surface; and
impinging a primary ion beam on the target surface with an incident angle with respect to the normal of the top surface of the fin, the incident angle being different from zero degrees,
wherein the primary ion beam, upon reaching the first target surface, scatters and generates a secondary ion beam, and at least a portion of the secondary ion beam dopes the first sidewall surface of the fin.

### Claim 18 (depends on 17)

The method of claim 17, wherein a portion of the secondary ion beam dopes the top surface of the fin.

### Claim 19 (depends on 18)

The method of claim 18, wherein the top surface of the fin is doped by a smaller portion of the secondary ion beam than the first sidewall wall surface of the fin.

### Claim 20 (depends on 17)

The method of claim 17, wherein the primary ion beam does not impinge on the top surface of the fin.