Semiconductor device

Patent metadata

Field	Value
Publication number	US-12342607-B2
Application number	US-202016794208-A
Country	US
Kind code	B2
Filing date	Feb 18, 2020
Priority date	Apr 16, 2019
Publication date	Jun 24, 2025
Grant date	Jun 24, 2025

Abstract

A semiconductor device includes a transistor portion which includes a plurality of gate structure portions, and a diode portion which includes a cathode region in a lower surface of a semiconductor substrate. Each of the gate structure portions includes a gate trench portion, an emitter region of a first conductive type which is provided between an upper surface of the semiconductor substrate and a drift region to abut on the gate trench portion, and a base region of a second conductive type which is provided between the emitter region and the drift region to abut on the gate trench portion. A first threshold of the gate structure portion with a shortest distance to the cathode region in a top view is lower than a second threshold of the gate structure portion with a longest distance to the cathode region by 0.1 V or more and 1 V or less.

First claim

What is claimed is:

1. A semiconductor device, comprising:
a semiconductor substrate which includes a drift region of a first conductive type;
a transistor portion which includes a plurality of gate structure portions in an upper surface of the semiconductor substrate;
an emitter electrode; and
a diode portion which includes a cathode region of the first conductive type, which has a higher doping concentration than the drift region, in a lower surface of the semiconductor substrate,
wherein each of the gate structure portions includes
a gate trench portion which is provided to reach the drift region from the upper surface of the semiconductor substrate,
an emitter region of the first conductive type which is provided between the upper surface of the semiconductor substrate and the drift region to abut on the gate trench portion and has a higher doping concentration than the drift region, and
a base region of a second conductive type which is provided between the emitter region and the drift region to abut on the gate trench portion,
wherein a first threshold voltage of the gate structure portion with a shortest distance to the cathode region in a top view is lower than a second threshold voltage of the gate structure portion with a longest distance to the cathode region by 0.1 V or more and 1 V or less, and
wherein the gate trench portion of each of the plurality of gate structure portions has a longitudinal direction that is the same for the plurality of gate structure portions, wherein there is a boundary between the transistor portion and the diode portion extending in the longitudinal direction, wherein the semiconductor device further comprises one or more emitter-connected trench portions each of which is conductively connected to the emitter electrode, wherein a boundary trench portion that is one of the one or more emitter-connected trench portions is disposed at the boundary between the transistor portion and the diode portion and extends in the longitudinal direction,
wherein the boundary trench portion has a transistor portion side on which the transistor portion is located, wherein the boundary trench portion has a diode portion side on which the diode portion is located, and wherein the transistor portion side of the boundary trench portion has the emitter region adjacent the boundary trench portion and there is no emitter region provided on the diode portion side of the boundary trench portion adjacent the boundary trench portion.

2. The semiconductor device according to claim 1 ,
wherein the gate structure portion having the first threshold voltage is provided in parallel with an end side of the cathode region in a top view.

3. The semiconductor device according to claim 1 ,
wherein the gate trench portion is provided to have a longitudinal side in a direction parallel with an end side of the cathode region,
wherein the transistor portion includes the gate structure portion, and a plurality of gate mesa portions which are provided along the longitudinal side of the gate trench portion, and
wherein the gate structure portion having the first threshold voltage is provided in a gate mesa portion with a shortest distance to the cathode region among the plurality of gate mesa portions.

4. The semiconductor device according to claim 3 ,
wherein a channel density of the gate mesa portion having the first threshold voltage is higher than the channel density of the gate mesa portion having the second threshold voltage.

5. The semiconductor device according to claim 4 ,
wherein the gate mesa portion includes the emitter region and a contact region of the second conductive type, which has a higher doping concentration than the base region, in the upper surface of the semiconductor substrate, and
wherein an area ratio of the contact region to the emitter region in an upper surface of the gate mesa portion having the first threshold voltage is smaller than an area ratio of the contact region to the emitter region in the upper surface of the gate mesa portion having the second threshold voltage.

6. The semiconductor device according to claim 1 ,
wherein the gate trench portion includes
a gate conductive portion, and
a gate dielectric film which is provided between the gate conductive portion and the semiconductor substrate, and
wherein a film thickness of the gate dielectric film in the gate trench portion of the gate structure portion having the first threshold voltage is smaller than a film thickness of the gate dielectric film in the gate trench portion of the gate structure portion having the second threshold voltage.

7. The semiconductor device according to claim 1 ,
wherein a doping concentration of the base region of the gate structure portion having the first threshold voltage is lower than a doping concentration of the base region of the gate structure portion having the second threshold voltage.

8. The semiconductor device according to claim 1 ,
wherein the transistor portion includes the gate trench portion and a emitter-connected trench portion,
wherein a density of the gate trench portion in a proximity region of the transistor portion abutting on the cathode region in a top view is higher than a density of the gate trench portion in a center region in a region with a longest distance to the cathode region, and
wherein the gate structure portion having the first threshold voltage is provided in the proximity region.

9. The semiconductor device according to claim 1 ,
wherein the diode portion includes an upper surface side lifetime control region which has a shorter carrier lifetime than other regions, on an upper surface side of the semiconductor substrate,
wherein the upper surface side lifetime control region is provided to extend to a proximity region of the transistor portion abutting on the cathode region in a top view, and
wherein the gate structure portion having the first threshold voltage is provided in the proximity region.

10. The semiconductor device according to claim 1 ,
wherein the cathode region has a long side in a top view, and
wherein the gate structure portion having the first threshold voltage is provided at a position facing a center of the long side of the cathode region, and is not provided at a position facing either end of the long side.

11. The semiconductor device according to claim 1 ,
wherein the cathode region has a long side in a top view, and
wherein the gate trench portion intersects with the long side of the cathode region in a top view.

12. The semiconductor device according to claim 1 , further comprising:
an interlayer dielectric film which is provided on an upper side of the upper surface of the semiconductor substrate, and includes a contact hole; and
an emitter electrode which is provided on an upper side of the interlayer dielectric film, and comes into contact with the semiconductor substrate through the contact hole,
wherein the gate trench portion extends in a predetermined extending direction in the upper surface of the semiconductor substrate, and
wherein the contact hole which has a longitudinal side in a direction different from the extending direction is disposed between the gate structure portion having the first threshold voltage and an end side of the semiconductor substrate in the extending direction.

13. The semiconductor device according to claim 1 ,
wherein the first threshold voltage is lower than the second threshold voltage by 0.1 V or more and 0.5 V or less.

14. The semiconductor device according to claim 1 , wherein the one or more emitter-connected trench portions comprise a plurality of emitter-connecte

Assignees

• Fuji Electric Co Ltd

Inventors

• Mitsuzuka Kaname
• SHIRAKAWA Tohru
• AJIKI Toru
• Onozawa Yuichi

Classifications

• H10D84/811 Primary

  Combinations of field-effect devices and one or more diodes, capacitors or resistors · CPC title

• H10D64/117

  Recessed field plates, e.g. trench field plates or buried field plates · CPC title

• H10D62/393 Primary

  Body regions of DMOS transistors or IGBTs  (cell layout of DMOS H10D62/127) · CPC title

• H10D12/481

  having gate structures on slanted surfaces, on vertical surfaces, or in grooves, e.g. trench gate IGBTs · CPC title

• H10D8/422

  PN diodes having the PN junctions in mesas · CPC title