Semiconductor device

Patent metadata

Field	Value
Publication number	US-12302602-B2
Application number	US-202217682994-A
Country	US
Kind code	B2
Filing date	Feb 28, 2022
Priority date	Sep 8, 2021
Publication date	May 13, 2025
Grant date	May 13, 2025

Abstract

According to one embodiment, a semiconductor device includes a first electrode, a second electrode, and a semiconductor layer between the first electrode and the second electrode. A third electrode is in the semiconductor layer. The third electrode extends in a second direction orthogonal to the first direction. A plurality of fourth electrodes are connected to the second electrode and extend in the first direction into the semiconductor layer. The fourth electrodes are spaced from one another along the second direction. A fifth electrode that is electrically isolated from the first electrode and between the first electrode and the plurality of fourth electrodes. The fifth electrode extends in the second direction and contacts the lower ends of the plurality of fourth electrodes in the trench.

First claim

What is claimed is:

1. A semiconductor device, comprising:
a first electrode;
a second electrode;
a semiconductor layer between the first electrode and the second electrode in a first direction;
a third electrode in the semiconductor layer, the third electrode extending in a second direction orthogonal to the first direction;
a plurality of fourth electrodes that are directly connected to the second electrode and extend in the first direction into the semiconductor layer, the plurality of fourth electrodes being spaced from one another along the second direction; and
a fifth electrode isolated from the first electrode, the fifth electrode being between the first electrode and the plurality of fourth electrodes and extending in the second direction, the fifth electrode contacting ends of the plurality of fourth electrodes, wherein
each of the fourth electrodes extends in the first direction to a point that is a distance from the first electrode along the first direction that is less than is a distance from the third electrode to first electrode along the first direction.

2. The semiconductor device according to claim 1 , wherein
the fourth electrodes comprise a metal, and
the fifth electrode comprises silicon.

3. The semiconductor device according to claim 1 , further comprising:
an insulating material between the semiconductor layer and the third electrode, between the third electrode and the fourth electrodes, between the semiconductor layer and the fourth electrodes, and between the semiconductor layer and the fifth electrode.

4. The semiconductor device according to claim 1 , wherein the third electrode surrounds at least one of the plurality of fourth electrodes in a plane orthogonal to the first direction.

5. The semiconductor device according to claim 1 , wherein a ratio of an occupied length of the fourth electrodes per a unit length along the second direction in a termination region is higher than a ratio of an occupied length of the fourth electrodes per the unit length along the second direction in a cell region.

6. The semiconductor device according to claim 1 , further comprising:
a plurality of third electrodes extending lengthwise in the second direction and spaced from one another in a third direction orthogonal to the first and second directions.

7. The semiconductor device according to claim 6 , wherein the fourth electrodes are at positions along the second direction that are the same as one another.

8. The semiconductor device according to claim 6 , wherein the fourth electrodes are at positions along the second direction that are different from one another.

9. The semiconductor device according claim 1 , wherein the semiconductor layer includes:
a first region that is contacting the first electrode and that is of a first conductivity type;
a second region that is contacting the second electrode and that is of the first conductivity type; and
a third region that is contacting the first region and the second region and that is of a second conductivity type.

10. The semiconductor device according to claim 9 , wherein an end of each of the fourth electrodes is located closer to the first electrode along the first direction than is an interface between the first region and the third region.

11. A semiconductor device, comprising:
a first electrode;
a second electrode;
a semiconductor layer between the first electrode and the second electrode in a first direction; and
a first plurality of trenches extending into the semiconductor layer in the first direction and lengthwise in a second direction orthogonal to the first direction, wherein
each trench in the first plurality of trenches includes therein:
a first insulating material,
a gate electrode in the first insulating material, the first insulating material separating the gate electrode and the semiconductor layer, the gate electrode extending lengthwise in the second direction,
a plurality of fourth electrodes that are connected to the second electrode and extend in the first direction into the trench to a depth greater than a lowermost end of the gate electrode in the first direction, the plurality of fourth electrodes being spaced from one another along the second direction, the first insulating material being between adjacent fourth electrodes and between the fourth electrodes and the gate electrode, and
a fifth electrode in the first insulating material between the first electrode and the plurality of fourth electrodes in the first direction, the fifth electrode extending in the second direction and contacting lowermost ends of the plurality of fourth electrodes.

12. The semiconductor device according to claim 11 , wherein
the plurality of fourth electrodes are metal, and
the fifth electrode is doped polysilicon.

13. The semiconductor device according to claim 11 , wherein an uppermost end of each of the plurality of fourth electrodes extends in the first direction above an uppermost surface of the semiconductor layer.

14. The semiconductor device according to claim 13 , wherein a metal film connects fourth electrodes in adjacent trenches.

15. The semiconductor device according to claim 14 , further comprising:
a source plug connected to the metal film and extending in the first direction into the semiconductor layer between adjacent trenches.

16. The semiconductor device according to claim 14 , wherein the metal film directly contacts the second electrode.

17. The semiconductor device according to claim 11 , wherein
a ratio of an occupied length of the fourth electrodes per a unit length along the second direction in a termination region is higher than a ratio of an occupied length of the fourth electrodes per a unit length along the second direction in a cell region.

18. The semiconductor device according to claim 11 , further comprising:
a second plurality of trenches extending into the semiconductor layer in the first direction and lengthwise in a third direction orthogonal to the first direction and different from the third direction, the second plurality of trenches being in a region of the semiconductor layer different from the first plurality of trenches, wherein
each trench in the second plurality of trenches includes therein:
a second first insulating material,
a second gate electrode in the second first insulating material, the first second insulating material separating the second gate electrode and the semiconductor layer, the second gate electrode extending lengthwise in the third direction,
a plurality of second fourth electrodes that are connected to the second electrode and extend in the first direction into the respective trench in the second plurality of trenches to a depth greater than a lowermost end of the second gate electrode in the first direction, the plurality of second fourth electrodes being spaced from one another along the third direction, the second first insulating material being between adjacent second fourth electrodes and between the second fourth electrodes and the second gate electrode, and
a second fifth electrode in the second first insulating material between the first electrode and the plurality of second fourth electrodes in the first direction, the second fifth electrode extending in the third direction and contacting lowermost ends of the plurality of second fourth electrodes.

19. The semiconductor device according to claim 11 , wherein the fourth electrodes are at positions along the second direction that are the same as one another.

Assignees

• Toshiba Kk
• Toshiba Electronic Devices & Storage Corp

Inventors

• Baba Shotaro
• Katou Hiroaki
• Shimomura Saya
• Nishiwaki Tatsuya

Classifications

• H10D64/2527

  for vertical devices wherein the source or drain electrodes are recessed in semiconductor bodies · CPC title

• H10D64/256

  for lateral devices wherein the source or drain electrodes are recessed in semiconductor bodies (source or drain electrodes of TFTs H10D30/673) · CPC title

• H10D62/127

  of cellular field-effect devices, e.g. multicellular DMOS transistors or IGBTs · CPC title

• H10D30/665

  having edge termination structures · CPC title

• H10D64/518

  characterised by their lengths or sectional shapes · CPC title