Semiconductor device with insulating section of varying thickness

• US 9,871,131 B2
• Filed: 08/30/2016
• Issued: 01/16/2018
• Est. Priority Date: 03/09/2016
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Kobayashi, Kenya
• Primary Examiner(s): LUKE, DANIEL M
• Application Number:
  US15/251,805
• Publication Number:
  US 20170263752A1
• Time in Patent Office: 504 Days
• CPC Class Codes: H01L 29/0696 of cellular field-effect devices, e.g. multicellular DMOS transistors or IGBTs
• CPC Class Codes: H01L 29/0886 Shape
• CPC Class Codes: H01L 29/407 Recessed field plates, e.g. trench field plates, buried field plates
• CPC Class Codes: H01L 29/41766 with at least part of the source or drain electrode having contact below the semiconductor surface, e.g. the source or drain electrode formed at least partially in a groove or with inclusions of conductor inside the semiconductor H01L29/41733 - H01L29/41758 take precedence
• CPC Class Codes: H01L 29/42368 the thickness being non-uniform
• CPC Class Codes: H01L 29/66734 with a step of recessing the gate electrode, e.g. to form a trench gate electrode
• CPC Class Codes: H01L 29/7811 with an edge termination structure guard regions per se H01L29/0619; field plates per se H01L29/402
• CPC Class Codes: H01L 29/7813 with trench gate electrode, e.g. UMOS transistors trench gate electrodes per se H01L29/4236

Abstract

A semiconductor device includes a first semiconductor region of a first conductivity type, a second semiconductor region of a second conductivity type on the first semiconductor region, a first electrode surrounded by the first semiconductor region and including a first electrode portion and a second electrode portion provided on the first electrode portion, and a first insulating section including first and second insulating portions. The second insulating portion is arranged side by side with the second electrode portion in a second direction perpendicular to a first direction from the first semiconductor region to the second semiconductor region. The first insulating portion is arranged side by side with the first electrode portion in the second direction. A length and a thickness of the first insulating portion in the first direction are greater than a length and a thickness of the second insulating portion in the first direction, respectively.

Claims

1. A semiconductor device comprising:

a first semiconductor region of a first conductivity type;

a second semiconductor region of a second conductivity type provided on the first semiconductor region;

a third semiconductor region of the first conductivity type selectively provided on the second semiconductor region;

a first electrode surrounded by the first semiconductor region, the first electrode including

a first electrode portion including a first end of the first electrode in a first direction from the first semiconductor region to the second semiconductor region, and

a second electrode portion provided on the first electrode portion;

a first insulating section provided between the first electrode and the first semiconductor region, the first insulating section including

a second insulating portion arranged side by side with the second electrode portion in a second direction perpendicular to the first direction, and

a first insulating portion arranged side by side with the first electrode portion in the second direction, a length of the first insulating portion in the first direction being greater than a length of the second insulating portion in the first direction, and a thickness of the first insulating portion in the second direction being greater than a thickness of the second insulating portion in the second direction;

a gate electrode provided on a second end of the first electrode opposite the first end in the first direction such that a width of the gate electrode in the second direction is approximately equal to a width of the first electrode portion in the second direction; and

a gate insulating section provided between the gate electrode and the second semiconductor region.

2. The semiconductor device according to claim 1, further comprising a plurality of first electrodes including the first electrode, each of the plurality of first electrodes including a corresponding first electrode portion and a corresponding second electrode portion,

and further comprising a plurality of first insulating sections including the first insulating section, each of the plurality of first insulating sections including a corresponding first insulating portion and a corresponding second insulating portion,

each of the plurality of first insulating sections is provided between a corresponding one of the plurality of first electrodes and the first semiconductor region, and

a length of the first semiconductor region between adjacent second insulating portions in the second direction is greater than a length of the first semiconductor region between adjacent first insulating portions in the second direction.

3. The semiconductor device according to claim 2, further comprising a plurality of gate electrodes including the gate electrode,

and further comprising a plurality of gate insulating sections including the gate insulating section,

each of the plurality of gate electrodes is provided on a corresponding one of the plurality of first electrodes,

each of the plurality of gate insulating sections is provided between a corresponding one of the plurality of gate electrodes and the second semiconductor region, and

a length of the first semiconductor region between adjacent first insulating portions in the second direction is 0.01 times or more and 0.6 times or less a distance between adjacent gate insulating sections in the second direction.

4. The semiconductor device according to claim 1, wherein a length of the first electrode in the first direction is 5 times or more and 15 times or less a thickness of the first insulating portion in the second direction.

5. The semiconductor device according to claim 1, wherein the width of the gate electrode in the second direction is approximately equal to the width of the first electrode in the second direction.

6. The semiconductor device according to claim 1, wherein a thickness of the gate insulating section in the second direction is less than the thickness of the first insulating portion.

7. The semiconductor device according to claim 1, further comprising:

a fourth semiconductor region of the second conductivity type selectively provided on the second semiconductor region; and

a source electrode provided on the third semiconductor region and the fourth semiconductor region and electrically connected to the third semiconductor region and the fourth semiconductor region.

8. The semiconductor device according to claim 1, wherein the first electrode and the gate electrode are separate from each other.

9. A semiconductor device comprising:

a first semiconductor region of a first conductivity type;

a second semiconductor region of a second conductivity type provided on the first semiconductor region;

a third semiconductor region of the first conductivity type selectively provided on the second semiconductor region;

a fourth semiconductor region of the second conductivity type selectively provided on the second semiconductor region;

a first electrode surrounded by the first semiconductor region;

a first insulating section provided between the first electrode and the first semiconductor region;

a gate electrode provided on one end portion of the first electrode in a first direction from the first semiconductor region to the second semiconductor region, a width of the gate electrode in a second direction perpendicular to the first direction being approximately equal to a width of another end portion of the first electrode in the second direction, the another end portion being opposite the one end portion in the first direction;

a gate insulating section provided between the gate electrode and the second semiconductor region, a thickness of the gate insulating section in the second direction being less than a thickness of the first insulating section in the second direction; and

a source electrode provided on the third semiconductor region and the fourth semiconductor region and electrically connected to the third semiconductor region and the fourth semiconductor region.

10. The semiconductor device according to claim 9, wherein the first electrode includes a first electrode portion, and a second electrode portion provided on the first electrode portion.

11. The semiconductor device according to claim 10, wherein the first insulating section includes:

a first insulating portion arranged side by side with the first electrode portion in the second direction, and

a second insulating portion arranged side by side with the second electrode portion in the second direction.

12. The semiconductor device according to claim 11, wherein a length of the first insulating portion in the first direction is greater than a length of the second insulating portion in the first direction.

13. The semiconductor device according to claim 11, wherein a thickness of the first insulating portion in the second direction is greater than a thickness of the second insulating portion in the second direction.

14. The semiconductor device according to claim 11, wherein a length of the first electrode in the first direction is 5 times or more and 15 times or less a thickness of the first insulating portion in the second direction.

15. The semiconductor device according to claim 9, further comprising a plurality of first electrodes including the first electrode,

and further comprising a plurality of first insulating sections including the first insulating section, each of the plurality of first insulating sections including a corresponding first insulating portion and a corresponding second insulating portion, and

each of the plurality of first insulating sections is provided between a corresponding one of the plurality of first electrodes and the first semiconductor region.

16. The semiconductor device according to claim 15, wherein a length of the first semiconductor region between adjacent second insulating portions in the second direction is greater than a length of the first semiconductor region between adjacent first insulating portions in the second direction.

17. The semiconductor device according to claim 15, further comprising a plurality of gate electrodes including the gate electrode,

and further comprising a plurality of gate insulating sections including the gate insulating section, and

each of the plurality of gate electrodes is provided on a corresponding one of the plurality of first electrodes.

18. The semiconductor device according to claim 17, wherein each of the plurality of gate insulating sections is provided between a corresponding one of the plurality of gate electrodes and the second semiconductor region.

19. The semiconductor device according to claim 18, wherein a length of the first semiconductor region between adjacent first insulating portions in the second direction is 0.01 times or more and 0.6 times or less a distance between adjacent gate insulating sections in the second direction.

20. The semiconductor device according to claim 9, wherein the first electrode and the gate electrode are separate from each other.