Trench shielding structure for semiconductor device and method

• US 9,306,018 B2
• Filed: 03/17/2014
• Issued: 04/05/2016
• Est. Priority Date: 11/14/2008
• Status: Active Grant

• Current Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Original Assignee: Semiconductor Components Industries LLC (ON Semiconductor Corporation)
• Inventors: Burke, Peter A., Grivna, Gordon M., Venkatraman, Prasad
• Primary Examiner(s): WOLDEGEORGIS, ERMIAS T
• Application Number:
  US14/216,914
• Publication Number:
  US 20140197483A1
• Time in Patent Office: 750 Days
• US Class Current: 1/1
• CPC Class Codes: H01L 29/0696 of cellular field-effect devices, e.g. multicellular DMOS transistors or IGBTs
• CPC Class Codes: H01L 29/40114 the electrodes comprising a conductor-insulator-conductor-insulator-semiconductor structure
• CPC Class Codes: H01L 29/407 Recessed field plates, e.g. trench field plates, buried field plates
• CPC Class Codes: H01L 29/41741 for vertical or pseudo-vertical devices
• 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 29/4236 within a trench, e.g. trench gate electrode, groove gate electrode
• CPC Class Codes: H01L 29/42372 characterised by the conducting layer, e.g. the length, the sectional shape or the lay-out H01L29/42324 takes precedence
• CPC Class Codes: H01L 29/4238 characterised by the surface lay-out
• CPC Class Codes: H01L 29/456 on silicon
• CPC Class Codes: H01L 29/4925 with a multiple layer structure, e.g. several silicon layers with different crystal structure or grain arrangement with only a vertical doping structure or vertical doping variation H01L29/4916
• CPC Class Codes: H01L 29/4933 with a silicide layer contacting the silicon layer, e.g. Polycide gate with a barrier layer between the silicide and silicon layers H01L29/4941
• 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
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A shielding structure for a semiconductor device includes a plurality of trenches. The trenches include passivation liners and shield electrodes, which are formed therein. In one embodiment, the shielding structure is placed beneath a control pad. In another embodiment, the shielding structure is placed beneath a control runner.

Claims

1. A semiconductor device structure comprising:

a region of semiconductor material having a major surface, an active region and a contact region;

a first trench structure formed in the region of semiconductor material and extending from the active region to the contact region, wherein the first trench structure includes a control electrode layer and a shield electrode layer, and wherein the shield electrode layer terminates in the contact region and is recessed within the first trench such that no portion of the shield electrode layer in the contact region overlaps the major surface of the region of semiconductor material;

a first conductive layer the control electrode layer; and

a second conductive layer contacting the shield electrode layer within the first trench structure below the major surface.

2. The structure of claim 1, wherein the control electrode layer terminates in the contact region and is recessed within the first trench such that no portion of the control electrode layer in the contact region overlaps the major surface of the semiconductor material, and wherein the first conductive layer contacts the control electrode layer within the first trench structure below the major surface.

3. The structure of claim 2, wherein the first trench structure includes a gate dielectric layer separating the control electrode layer from the region of semiconductor material, and wherein the shield electrode layer in the contact region is separated from the control electrode layer at the major surface by an insulator layer that is thicker than the gate dielectric layer.

4. The structure of claim 2, wherein the first and second conductive layers comprise conductive plugs.

5. The structure of claim 1, wherein the structure further comprises a second contact region formed within the active region for further contacting the shield electrode layer within the active region.

6. The structure of claim 1, wherein the second conductive layer makes contact to the shield electrode layer adjacent an edge of the semiconductor device, and wherein the first conductive layer is between the active area and the second conductive layer.

7. The structure of claim 1, wherein the control electrode layer is separated from the region of semiconductor material by a first insulator layer, and wherein the shield electrode layer is separated from the region of semiconductor material by a second insulator layer, and wherein the control electrode layer is separated from the shield electrode layer by a third insulator layer, wherein the second and third insulator layers are thicker than the first insulator layer.

8. The structure of claim 1, wherein the second conductive layer includes a portion that laterally wraps around an end portion of the first conductive layer, and wherein the first and second conductive layers do not overlap.

9. A semiconductor device structure comprising:

a region of semiconductor material having a major surface, an active area, and a contact area;

a trench having a striped shape formed in the region of semiconductor material and extending from the active area to the contact area;

a source region adjacent the trench in the active area;

a shield electrode formed in the trench and separated from the region of semiconductor material by a first insulator layer;

a control electrode formed in the trench and separated from the region of semiconductor material by a second insulator layer and separated from the shield electrode by a third insulator layer, wherein shield electrode and the control electrode terminate in the contact area, and wherein the shield electrode is recessed below the major surface of the region of semiconductor material in the contact area without overlapping the major surface in the contact area;

a first conductive structure contacting the control electrode in the contact area; and

a second conductive structure contacting the shield electrode inside the trench within the contact area and contacting the source region in the active area, wherein the second conductive structure includes a portion that laterally wraps around an end of the first conductive structure.

10. The structure of claim 9, wherein the first and third insulator layers are thicker than the second insulator layer.

11. The structure of claim 9 further comprising a metal silicide layer formed on the control electrode and extending along the control electrode from the active area to the contact area.

12. The structure of claim 9, wherein the control electrode is recessed below the major surface of the region of semiconductor material in the contact area without overlapping the major surface in the contact area, and wherein the first conductive structure contacts the control electrode inside the trench within the contact area.

13. A semiconductor device structure comprising:

a region of semiconductor material having a major surface, an active area, and a contact area;

a trench having a striped shape formed in the region of semiconductor material and extending from the active area to the contact area;

a source region adjacent the trench in the active area;

a shield electrode formed in the trench and separated from the region of semiconductor material by a first insulator layer;

a control electrode formed in the trench and separated from the region of semiconductor material by a second insulator layer and separated from the shield electrode by a third insulator layer, wherein the shield electrode and the control electrode terminate in the contact area, and wherein the shield electrode terminates in the contact area without overlapping the major surface of the region of semiconductor material in the contact area, and wherein the shield electrode is recessed below the major surface of the region of semiconductor material in the contact area, and wherein the first and third insulator layers are thicker than the second insulator layer;

a first conductive structure contacting the control electrode in the contact area; and

a second conductive structure contacting the shield electrode within the contact area and contacting the source region in the active area.

14. The structure of claim 13, wherein the second conductive structure includes a portion that laterally wraps around an end of the first conductive structure.

15. The structure of claim 13, wherein the first conductive structure and the second conductive structure do not overlap.

16. The structure of claim 13, wherein the first conductive structure and the second conductive structure comprise the same material.

17. The structure of claim 13, wherein the third insulator layer is thicker than the first insulator layer.

18. The structure of claim 13, wherein the second conductive structure contacts the shield electrode in the active area.

19. The structure of claim 18, wherein the second conductive structure contacts the shield electrode at a location of the active area that is offset from a central portion of the semiconductor device.

20. The structure of claim 13, wherein the second conductive structure includes a conductive plug.

21. A semiconductor device structure comprising:

a region of semiconductor material having a major surface, an active region and a contact region;

a first trench structure formed in the region of semiconductor material and extending from the active region to the contact region, wherein the first trench structure includes a control electrode layer and a shield electrode layer, and wherein the control electrode layer terminates in the contact region such that no portion of the control electrode layer in the contact region overlaps the major surface of the region of semiconductor material;

a first conductive layer contacting to the control electrode layer below the major surface; and

a second conductive layer coupled to the shield electrode layer.

22. The structure of claim 21, wherein the shield electrode layer in the contact region terminates such that no portion of the shield electrode layer in the contact region overlaps the major surface of the semiconductor material, and wherein the second conductive layer contacts the shield electrode layer within the first trench structure below the major surface.

23. The structure of claim 21, wherein the shield electrode layer overlaps onto the major surface in the contact region, and wherein the second conductive layer makes contact to the shield electrode layer in the contact region at a location spaced apart from the first trench structure.

24. The structure of claim 21, wherein the second conductive layer includes a portion that laterally wraps around an end portion of the first conductive layer, and wherein the first and second conductive layers do not overlap.