# US 10,374,056 B2 · Latch-up resistant transistor

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- Number: US 10,374,056 B2
- Document ID: US10374056B2
- Status: Granted
- Kind: B2
- Application number: 15/337,829
- Filed: 2016-10-28
- Published: 2017-05-04
- Granted: 2019-08-06
- Earliest claimed: 2015-10-30
- Assignees: Infineon Technologies Austria AG
- Applicants: Infineon Technologies Austria AG
- Inventors: Katarzyna Kowalik-Seidl; Bjoern Fischer; Winfried Kaindl; Markus Schmitt; Matthias Wegscheider
- Web page: https://patentgrep.com/patent/US10374056B2

## CPC

- H10D 12/032: {of vertical IGBTs}
- H10D 12/035: {Etching a recess in the emitter region (having a recessed gate H10D12/038)}
- H10D 12/441: {Vertical IGBTs}
- H10D 12/461: {having non-planar surfaces, e.g. having trenches, recesses or pillars in the surfaces of the emitter, base or collector regions}
- H10D 30/0293: {using formation of insulating sidewall spacers}
- H10D 30/0295: {using recessing of the source electrodes}
- H10D 30/66: Vertical DMOS [VDMOS] FETs
- H10D 62/111: {Multiple RESURF structures, e.g. double RESURF or 3D-RESURF structures}
- H10D 64/256: {for lateral devices wherein the source or drain electrodes are recessed in semiconductor bodies (source or drain electrodes of TFTs H10D30/673)}
- 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)}
- H10D 62/127: {of cellular field-effect devices, e.g. multicellular DMOS transistors or IGBTs}
- H10D 62/154: {Dispositions}
- H10D 62/393: {Body regions of DMOS transistors or IGBTs (cell layout of DMOS H10D62/127)}
- H10P 32/1406: {by ion implantation}
- 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

Disclosed is a method for producing a transistor device and a transistor device. The method includes: forming a source region of a first doping type in a body region of a second doping type in a semiconductor body; and forming a low-resistance region of the second doping type adjoining the source region in the body region. Forming the source region includes implanting dopant particles of the first doping type using an implantation mask via a first surface of the semiconductor body into the body region. Implanting the doping particles of the first doping type includes a tilted implantation.

## Claims

### Claim 1

A method, comprising:
forming a drain region at a first side of a semiconductor body;
forming a drift region of a first doping type above the drain region in the semiconductor body;
forming a body region of a second doping type above the drift region in the semiconductor body;
forming a source region of the first doping type in the body region at a second side of the semiconductor body opposite the first side; and
forming a low-resistance region of the second doping type adjoining the source region in the body region,
wherein forming the source region comprises implanting dopant particles of the first doping type using an implantation mask via a first surface of the semiconductor body into the body region,
wherein implanting the doping particles of the first doping type comprises a tilted implantation,
wherein forming the low-resistance region comprises implanting dopant particles of the second doping type using the implantation mask,
wherein the method further comprises:
forming a spacer on at least one sidewall of the implantation mask; and
after forming the spacer, implanting dopant particles of the second doping type into the first surface of the semiconductor body to form the low-resistance region of the second doping type in the body region, the spacer preventing the dopant particles of the second doping type from being implanted into the body region in close proximity to an edge of the implantation mask covered by the spacer.

### Claim 2 (depends on 1)

The method of claim 1, wherein forming the source region further comprises:
performing a first annealing process after implanting the dopant particles of the first doping type and before implanting the dopant particles of the second doping type.

### Claim 3 (depends on 2)

The method of claim 2, wherein a temperature of the first annealing process is in a range between 850° C. and 950° C.

### Claim 4 (depends on 1)

The method of claim 1, wherein forming the low-resistance region further comprises a second annealing process after implanting the dopant particles of the second doping type.

### Claim 5 (depends on 4)

The method of claim 4, wherein a temperature of the second annealing process is in a range between 850° C. and 950° C.

### Claim 6 (depends on 1)

The method of claim 1, wherein the tilted implantation has a tilt angle of between 10° and 45° relative to a vertical direction of the semiconductor body.

### Claim 7 (depends on 6)

The method of claim 6, wherein the tilt angle is between 20° and 40° relative to a vertical direction of the semiconductor body.

### Claim 8 (depends on 1)

The method of claim 1,
wherein implanting the doping particles of the first doping type comprises at least two tilted implantations,
wherein each of the at least two tilted implantations comprises an implantation vector with a lateral component, and
wherein the lateral components associated with the implantation vectors of the at least two tilted implantations are different from each other.

### Claim 9 (depends on 1)

The method of claim 1, wherein implanting the doping particles of the first doping type comprises two tilted implantations.

### Claim 10 (depends on 1)

The method of claim 1, wherein implanting the doping particles of the first doping type comprises four tilted implantations.

### Claim 11 (depends on 1)

The method of claim 1, wherein a thickness of the spacer is in a range between 100 nanometers and 500 nanometers.

### Claim 12 (depends on 1)

The method of claim 1, wherein a thickness of the spacer is in a range between 200 nanometers and 400 nanometers.

### Claim 13 (depends on 1)

The method of claim 1, wherein the implantation mask comprises a gate electrode and a gate dielectric arranged between the gate electrode and the semiconductor body.

### Claim 14 (depends on 1)

The method of claim 1, further comprising:
removing the implantation mask; and
forming a gate dielectric on the body region and a gate electrode on the gate dielectric.

### Claim 15 (depends on 1)

The method of claim 1, wherein the drain region is of one of the first doping type and the second doping type.

### Claim 16 (depends on 1)

The method of claim 1, wherein the semiconductor body further comprises a compensation region of the second doping type adjoining the body region and the drift region.

### Claim 17 (depends on 1)

The method of claim 1, wherein forming the spacer comprises:
forming a layer on the first surface of the semiconductor body and the implantation mask; and
etching the layer so as to maintain the layer only along the edge of the implantation mask where it forms the spacer.

### Claim 18 (depends on 17)

The method of claim 17, wherein the layer is an oxide layer and wherein forming the layer comprises one of a thermal oxidation and a deposition process.

### Claim 19 (depends on 1)

The method of claim 1, wherein forming the spacer comprises:
forming a resist layer on the first surface of the semiconductor body and the implantation mask; and
structuring the resist layer to form an opening in the resist layer spaced apart from the edge of the implantation mask, wherein a region of the resist layer between the opening and the edge of the implantation mask forms the spacer.

### Claim 20 (depends on 1)

The method of claim 1, further comprising:
forming a scattering layer on the first surface of the semiconductor body; and
after forming the scattering layer, implanting dopant particles of the second doping type through the scattering layer and into the first surface of the semiconductor body to form the low-resistance region of the second doping type in the body region.