# US 2018/0323189 A1 · Field-Effect Semiconductor Device Having a Heterojunction Contact

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- Number: US 2018/0323189 A1
- Document ID: US20180323189A1
- Status: Published application
- Kind: A1
- Application number: 16/022,263
- Filed: 2018-06-28
- Published: 2018-11-08
- Earliest claimed: 2012-09-04
- Assignees: Infineon Technologies Austria AG
- Applicants: Infineon Technologies Austria AG
- Inventors: Wolfgang Werner
- Web page: https://patentgrep.com/patent/US20180323189A1

## CPC

- H10D 84/811: {Combinations of field-effect devices and one or more diodes, capacitors or resistors}
- H10D 8/411: {PN diodes having planar bodies}
- H10D 8/60: Schottky-barrier diodes
- H10D 12/031: {of IGBTs}
- H10D 12/441: {Vertical IGBTs}
- H10D 30/015: {of FETs having heterojunction interface channels or heterojunction gate electrodes, e.g. HEMT}
- H10D 30/0297: {using recessing of the gate electrodes, e.g. to form trench gate electrodes}
- H10D 30/051: {of FETs having PN junction gates (H10D30/015 takes precedence)}
- H10D 30/0515: {of vertical FETs having PN homojunction gates}
- H10D 30/60: Insulated-gate field-effect transistors [IGFET] (H10D30/40 takes precedence)
- H10D 30/668: {having trench gate electrodes, e.g. UMOS transistors}
- H10D 30/831: {Vertical FETs having PN junction gate electrodes (Vertical SIT H10D30/202)}
- H10D 62/393: {Body regions of DMOS transistors or IGBTs (cell layout of DMOS H10D62/127)}
- H10D 62/40: Crystalline structures
- H10D 62/402: {Amorphous materials}
- H10D 62/82: Heterojunctions
- H10D 62/822: comprising only Group IV materials heterojunctions, e.g. Si/Ge heterojunctions
- H10D 62/83: being Group IV materials, e.g. B-doped Si or undoped Ge
- H10D 62/8325: {Silicon carbide}
- H10D 62/8503: {Nitride Group III-V materials, e.g. AlN or GaN}
- H10D 84/144: {in antiparallel diode configurations}
- H10D 84/146: {the built-in components being Schottky barrier diodes}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES

## Abstract

According to an embodiment of a semiconductor device, the semiconductor device includes a semiconductor body having a main surface, the semiconductor body including a drift region of monocrystalline SiC, the drift region being of a first conductivity type, and a metallization arranged at the main surface. In a cross-section which is substantially orthogonal to the main surface, the semiconductor body further includes a contact region of the monocrystalline SiC directly adjoining the drift region and the metallization, and an anode region of a semiconductor material having a lower band-gap than the monocrystalline SiC. The contact region is of a second conductivity type. The anode region is in ohmic contact with the metallization and forms a heterojunction with the drift region.

## Claims

### Claim 1

A semiconductor device, comprising:
a semiconductor body having a main surface, the semiconductor body comprising a drift region of monocrystalline SiC, the drift region being of a first conductivity type; and
a metallization arranged at the main surface,
wherein in a cross-section which is substantially orthogonal to the main surface, the semiconductor body further comprises:
a contact region of the monocrystalline SiC directly adjoining the drift region and the metallization, the contact region being of a second conductivity type; and
an anode region of a semiconductor material having a lower band-gap than the monocrystalline SiC, the anode region being in ohmic contact with the metallization and forming a heterojunction with the drift region.

### Claim 2 (depends on 1)

The semiconductor device of claim 1, wherein the anode region directly adjoins the contact region.

### Claim 3 (depends on 1)

The semiconductor device of claim 1, wherein the contact region directly adjoins the metallization at the main surface.

### Claim 4 (depends on 1)

The semiconductor device of claim 1, further comprising in the vertical cross-section, a further contact region of the monocrystalline SiC directly adjoining the drift region and the metallization, the further contact region being of the second conductivity type, wherein the heterojunction extends from the contact region to the further contact region.

### Claim 5 (depends on 1)

The semiconductor device of claim 1, wherein an extension of the contact region in a vertical direction perpendicular to the main surface is larger than an extension of the anode region in the vertical direction.

### Claim 6 (depends on 1)

The semiconductor device of claim 1, wherein the semiconductor material of the anode region is a non-crystalline band-gap material.

### Claim 7 (depends on 1)

The semiconductor device of claim 1, wherein a maximum doping concentration of the anode region is at least three orders of magnitude higher than a maximum doping concentration of the drift region.

### Claim 8 (depends on 1)

The semiconductor device of claim 1, wherein the anode region and the drift region form a diode.

### Claim 9 (depends on 1)

The semiconductor device of claim 1, further comprising a source region of the monocrystalline SiC in ohmic contact with the metallization, the source region being of the first conductivity type and having a higher maximum doping concentration than the drift region, wherein the heterojunction and the source region do not overlap in a projection onto the main surface.

### Claim 10 (depends on 9)

The semiconductor device of claim 9, further comprising a gate electrode arranged in a vertical trench extending from the main surface at least partly in the drift region, the gate electrode being insulated from the source region and the drift region by a gate dielectric region.

### Claim 11 (depends on 1)

The semiconductor device of claim 1, further comprising a body region of the monocrystalline SiC, the body region being of the second conductivity type and having a lower doping concentration than the contact region, the contact region being arranged between the body region and the anode region and between the body region and the metallization.

### Claim 12 (depends on 11)

The semiconductor device of claim 11, further comprising a gate electrode arranged in a vertical trench extending from the main surface at least partly in the drift region, the gate electrode being insulated from the drift region and the body region by a gate dielectric region.

### Claim 13 (depends on 1)

The semiconductor device of claim 1, wherein the anode region is of the second conductivity type.

### Claim 14 (depends on 1)

The semiconductor device of claim 1, wherein the semiconductor material of the anode region is silicon or germanium.

### Claim 15 (depends on 1)

The semiconductor device of claim 1, further comprising a gate electrode arranged in a vertical trench extending from the main surface at least partly in the drift region, the gate electrode being insulated from the monocrystalline SiC by a gate dielectric region.