Semiconductor device including a contact structure directly adjoining a mesa section and a field electrode

• US 9,847,395 B2
• Filed: 07/01/2016
• Issued: 12/19/2017
• Est. Priority Date: 07/03/2015
• Status: Active Grant

• Current Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Original Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Inventors: Laforet, David, Schwarz, Elisabeth, Weissnicht, Beate
• Primary Examiner(s): Ahmad, Khaja
• Application Number:
  US15/201,017
• Publication Number:
  US 20170005171A1
• Time in Patent Office: 536 Days
• Field of Search: None
• CPC Class Codes: H01L 23/585 comprising conductive layers or plates or strips or rods or rings H01L23/60, H01L23/62, H01L23/64, H01L23/66 take precedence
• CPC Class Codes: H01L 29/0696 of cellular field-effect devices, e.g. multicellular DMOS transistors or IGBTs
• CPC Class Codes: H01L 29/404 Multiple field plate structures
• CPC Class Codes: H01L 29/407 Recessed field plates, e.g. trench field plates, buried field plates
• CPC Class Codes: H01L 29/41725 Source or drain electrodes for field effect devices with monocrystalline semiconductor on source/drain region H01L29/0843
• CPC Class Codes: H01L 29/4238 characterised by the surface lay-out
• 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
• CPC Class Codes: H01L 29/861 Diodes

Abstract

A semiconductor device includes a gate structure that extends from a first surface into a semiconductor portion and that surrounds a transistor section of the semiconductor portion. A field plate structure includes a field electrode and extends from the first surface into the transistor section. A mesa section of the semiconductor portion separates the field plate structure and the gate structure. A contact structure includes a first portion directly adjoining the mesa section and a second portion directly adjoining the field electrode. The first and second portions include stripes and are directly connected to each other.

Claims

1. A semiconductor device, comprising:

a gate structure extending from a first surface into a semiconductor portion and surrounding a transistor section of the semiconductor portion;

a field plate structure extending from the first surface into the transistor section and comprising a field electrode;

a mesa section of the transistor section separating the field plate structure and the gate structure; and

a contact structure comprising a first portion directly adjoining the mesa section and a second portion directly adjoining the field electrode, wherein the first and second portions include stripes and are directly connected to each other.

2. The semiconductor device of claim 1, wherein the first portion includes stripes forming a closed, polygonal frame in a horizontal cross-section parallel to the first surface.

3. The semiconductor device of claim 1, wherein the first portion includes stripes forming a closed, regular polygonal frame in a horizontal cross-section parallel to the first surface.

4. The semiconductor device of claim 1, wherein the first portion includes four stripes forming a closed square frame in a horizontal cross-section parallel to the first surface.

5. The semiconductor device of claim 1, wherein the first portion forms a closed oval frame in a horizontal cross-section.

6. The semiconductor device of claim 1, wherein the second portion comprises a stripe extending from the first portion to a vertical projection of the field electrode, and wherein the vertical projection is perpendicular to the first surface.

7. The semiconductor device of claim 6, wherein the second portion includes a stripe and both end faces of the stripe directly adjoin the first portion.

8. The semiconductor device of claim 1, wherein the first portion includes at least four straight stripes forming a closed frame, and wherein the second portion extends through an opening of the frame and crosses a center of the opening.

9. The semiconductor device of claim 1, wherein the first portion is formed at a horizontal distance to the field plate structure.

10. The semiconductor device of claim 1, wherein the first portion overlaps with a vertical projection of the field plate structure perpendicular to the first surface.

11. The semiconductor device of claim 1, wherein the mesa section includes body zones forming a first pn junction with a drift structure and second pn junctions with source zones formed between the body zones and the first surface.

12. The semiconductor device of claim 11, wherein the gate structure includes a gate electrode and a gate dielectric separating the gate electrode from the body zones.

13. The semiconductor device of claim 1, wherein the gate structure forms a grid and a mesh of the grid includes the transistor section and the field plate structure.

14. The semiconductor device of claim 1, wherein the first and second portions comprise stripes of uniform width.

15. A semiconductor device, comprising:

gate structures extending from a first surface into a semiconductor portion and defining transistor sections of the semiconductor portion between neighboring ones of the gate structures;

spicular field plate structures extending from the first surface into the transistor sections and including field electrodes;

mesa sections of the transistor sections separating the field plate structures from each other and from the gate structures; and

contact structures each of which comprises a first portion directly adjoining one of the mesa sections and a second portion directly adjoining one of the field electrodes, wherein the first and second portions include stripes.

16. The semiconductor device of claim 15, wherein the first and second portions are directly connected to each other along a direction horizontal to the first surface.

17. The semiconductor device of claim 15, wherein the first portions of the contact structures assigned to neighboring ones of the field plate structures in a same transistor section are connected to each other along a longitudinal axis of the first portions.

18. The semiconductor device of claim 15, wherein the first portions of the contact structures assigned to neighboring ones of the field plate structures in a same transistor section are separated from each other.

19. The semiconductor device of claim 15, wherein the first and second portions are parallel stripes.

20. An electronic assembly, comprising:

a semiconductor device comprising;

a gate structure including a gate electrode and extending from a first surface into a semiconductor portion and surrounding a transistor section of the semiconductor portion;

a field plate structure extending from the first surface into the transistor section and comprising a field electrode;

a mesa section of the transistor section separating the field plate structure and the gate structure; and

a contact structure comprising a first portion directly adjoining the mesa section and a second portion directly adjoining the field electrode, wherein the first and second portions include stripes and are directly connected to each other; and

a gate driver circuit electrically connected or coupled to the gate electrode.