Semiconductor device

Patent metadata

Field	Value
Publication number	US-11942539-B2
Application number	US-202117471739-A
Country	US
Kind code	B2
Filing date	Sep 10, 2021
Priority date	Mar 24, 2021
Publication date	Mar 26, 2024
Grant date	Mar 26, 2024

Abstract

A semiconductor device includes a polycrystalline silicon part buried in a termination region of a silicon layer. The polycrystalline silicon part contacts the silicon layer, has a higher crystal grain density than the silicon layer, and includes a heavy metal. The silicon layer includes a drift layer located in a cell region and the termination region. The drift layer has a lower first-conductivity-type impurity concentration than a silicon substrate. The drift layer includes a same element of heavy metal as the heavy metal included in the polycrystalline silicon part.

First claim

What is claimed is:

1. A semiconductor device, comprising:
an upper electrode;
a lower electrode;
a silicon substrate positioned between the upper electrode and the lower electrode, the silicon substrate being of a first conductivity type and contacting the lower electrode;
a silicon layer positioned between the silicon substrate and the upper electrode, the silicon layer including
a cell region,
a side surface, and
a termination region positioned between the cell region and the side surface;

a gate electrode located in the cell region of the silicon layer;
a gate insulating film located between the gate electrode and the silicon layer; and
a polycrystalline silicon part buried in the termination region of the silicon layer,
the polycrystalline silicon part contacting the silicon layer, having a higher crystal grain density than the silicon layer, and including a heavy metal,
the silicon layer including
a drift layer located in the cell region and the termination region, the drift layer being of the first conductivity type and having a lower first-conductivity-type impurity concentration than the silicon substrate, the drift layer including a same element of heavy metal as the heavy metal included in the polycrystalline silicon part,
a base layer located on the drift layer of the cell region, the base layer being of a second conductivity type and contacting the upper electrode, and
a source layer located on the base layer, the source layer being of the first conductivity type, contacting the upper electrode, and having a higher first-conductivity-type impurity concentration than the drift layer,

the termination region not including the base layer contacting the upper electrode, the source layer contacting the upper electrode, and the gate electrode.

2. The device according to claim 1 , wherein
the polycrystalline silicon part continuously surrounds the cell region.

3. The device according to claim 1 , wherein
the gate electrode and the gate insulating film are located in a structure part buried in the silicon layer of the cell region, and
a distance between the polycrystalline silicon part and the lower electrode is shorter than a distance between the structure part and the lower electrode.

4. The device according to claim 3 , wherein
the structure part further includes a field plate electrode electrically connected with the upper electrode or the gate electrode, and
the field plate electrode is between the gate electrode and the silicon substrate.

5. The device according to claim 1 , wherein
the silicon layer further includes a channel stopper located between the drift layer and the polycrystalline silicon part,
the channel stopper is of the first conductivity type, and
the channel stopper has a higher first-conductivity-type impurity concentration than the drift layer.

6. The device according to claim 1 , wherein
a heavy metal concentration in the drift layer of the cell region is higher than a heavy metal concentration in the drift layer of a region between the polycrystalline silicon part and the side surface.

7. The device according to claim 1 , wherein
a heavy metal concentration in the drift layer of a region between the cell region and the polycrystalline silicon part is higher than a heavy metal concentration in the drift layer of a region between the polycrystalline silicon part and the side surface.

8. The device according to claim 1 , wherein
the heavy metal is Pt.

9. The device according to claim 1 , wherein
the heavy metal is Au.

10. The device according to claim 1 , wherein
the polycrystalline silicon part includes:
a first polycrystalline silicon part; and
a second polycrystalline silicon part positioned between the first polycrystalline silicon part and the side surface.

11. The device according to claim 10 , wherein
the gate electrode and the gate insulating film are located in a structure part buried in the silicon layer of the cell region, and
a distance between the first polycrystalline silicon part and the lower electrode is longer than a distance between the structure part and the lower electrode.

12. The device according to claim 10 , wherein
a distance between the second polycrystalline silicon part and the lower electrode is shorter than a distance between the first polycrystalline silicon part and the lower electrode.

13. The device according to claim 10 , wherein
the first polycrystalline silicon part and the second polycrystalline silicon part continuously surround the cell region.

14. The device according to claim 1 , wherein
the drift layer does not contact the upper electrode at an upper surface of the termination region.

15. The device according to claim 1 , wherein the polycrystalline silicon part is electrically insulated from the upper electrode.

Assignees

• Toshiba Kk
• Toshiba Electronic Devices & Storage Corp

Inventors

• Baba Shotaro
• Katou Hiroaki
• FUJINO Yuhki
• Tomita Kouta

Classifications

• H10W10/041

  of isolation regions comprising polycrystalline semiconductor materials · CPC title

• H10W10/40

  Isolation regions comprising polycrystalline semiconductor materials · CPC title

• H10P32/171

  being group IV material · CPC title

• H10P32/18

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• H10D8/00

  Diodes (variable-capacitance diodes H10D1/64; gated diodes H10D12/00) · CPC title