Semiconductor Device with Field Electrode and Contact Structure

• US 20160064496A1
• Filed: 08/07/2015
• Published: 03/03/2016
• Est. Priority Date: 08/27/2014
• Status: Active Grant

• Current Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Original Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Inventors: Siemieniec, Ralf, Blank, Oliver, Hutzler, Michael, Laforet, David, Ouvrard, Cedric, Yip, Li Juin
• Granted Patent: US 9,799,738 B2
• Time in Patent Office: 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 29/407 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 29/4238 characterised by the surface lay-out
• CPC Class Codes: H01L 29/7396 with a non planar surface, e.g. with a non planar gate or with a trench or recess or pillar in the surface of the emitter, base or collector region for improving current density or short circuiting the emitter and base regions H01L29/7398 takes precedence
• CPC Class Codes: H01L 29/7397 and a gate structure lying on a slanted or vertical surface or formed in a groove, e.g. trench gate IGBT
• 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 field electrode structure with a field electrode and a field dielectric surrounding the field electrode. A semiconductor body includes a transistor section surrounding the field electrode structure and including a source zone, a first drift zone section and a body zone separating the source zone and the first drift zone section. The body zone forms a first pn junction with the source zone and a second pn junction with the first drift zone section. A gate structure surrounds the field electrode structure and includes a gate electrode and a gate dielectric separating the gate electrode and the body zone. A contact structure directly adjoins the source and body zones and surrounds the field electrode structure equably with respect to the field electrode structure.

Claims

1. A semiconductor device, comprising:

a field electrode structure comprising a field electrode and a field dielectric surrounding the field electrode;

a semiconductor body including a transistor section surrounding the field electrode structure and comprising a source zone, a first drift zone section and a body zone separating the source zone and the first drift zone section, the body zone forming a first pn junction with the source zone and a second pn junction with the first drift zone section;

a gate structure surrounding the field electrode structure and comprising a gate electrode and a gate dielectric separating the gate electrode and the body zone;

a contact structure adjoining the source and body zones and surrounding the field electrode structure.

2. The semiconductor device of claim 1, wherein the field electrode extends substantially perpendicular to a plane parallel to a first surface of the semiconductor body.

3. The semiconductor device of claim 1, wherein a first extension of the field electrode is at most twice as large as a second extension orthogonal to the first extension.

4. The semiconductor device of claim 1, wherein a cross-sectional area of the field electrode is a circle.

5. The semiconductor device of claim 1, wherein a cross-sectional area of the contact structure has a concentric opening and a cross-sectional area of the opening and a cross-sectional area of the field electrode structure are geometrically similar.

6. The semiconductor device of claim 1, wherein a cross-sectional area of the contact structure and a cross-sectional area of the transistor section are geometrically similar.

7. The semiconductor device of claim 1, wherein a cross-sectional area of the contact structure is a ring.

8. The semiconductor device of claim 1, wherein in a plane parallel to a first surface the contact structure surrounds the field electrode structure at a constant distance.

9. The semiconductor device of claim 1, wherein a width of the contact structure varies as a function of an angular direction at a center point of the field electrode.

10. The semiconductor device of claim 1, wherein the contact structure directly adjoins the field electrode structure.

11. The semiconductor device of claim 1, wherein in a plane parallel to a first surface the transistor section is sandwiched between the field electrode structure and the gate structure.

12. The semiconductor device of claim 1, wherein gate structures of a plurality of transistor cells form a grid embedding transistor sections of the transistor cells.

13. The semiconductor device of claim 1, wherein in a plane parallel to a first surface the gate electrode is formed between the field electrode and the transistor section.

14. The semiconductor device of claim 1, wherein transistor sections of a plurality of transistor cells form a grid embedding gate structures and field electrode structures of the transistor cells.

15. The semiconductor device of claim 1, wherein a portion of the field dielectric separates the field electrode and the gate electrode.

16. The semiconductor device of claim 1, wherein an inner contour of the gate electrode is a circle.

17. A semiconductor device, comprising:

a field electrode structure comprising a field electrode and a field dielectric surrounding the field electrode;

a semiconductor body including a transistor section surrounding a plurality of field electrode structures and comprising a source zone, a first drift zone section and a body zone separating the source zone and the first drift zone section, the body zone forming a first pn junction with the source zone and a second pn junction with the first drift zone section;

a gate structure adjoining the transistor section on opposing sides and comprising a gate electrode and a gate dielectric separating the gate electrode and the body zone;

a contact structure adjoining the source and body zones and an ancillary contact structure adjoining the field electrode and overlapping with the transistor section around the field electrode structure.

18. The semiconductor device of claim 17, wherein a portion of the field dielectric separates the field electrode and the gate electrode.

19. The semiconductor device of claim 17, wherein the field electrode extends substantially perpendicular to a plane parallel to a first surface of the semiconductor body.

20. The semiconductor device of claim 17, wherein the field electrodes are arranged along a line.