Semiconductor Diode with Trench Structures

• US 20150097262A1
• Filed: 11/20/2014
• Published: 04/09/2015
• Est. Priority Date: 06/04/2012
• Status: Active Grant

• Current Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Original Assignee: Infineon Technologies Austria Ag (Infineon Technologies AG)
• Inventors: Mauder, Anton, Niedernostheide, Franz-Josef, Schulze, Hans-Joachim, Schulze, Holger
• Granted Patent: US 10,069,016 B2
• Time in Patent Office: Days
• US Class Current: 257/493
• CPC Class Codes: H01L 21/761 PN junctions
• CPC Class Codes: H01L 21/76224 using trench refilling with dielectric materials trench filling with polycristalline silicon H01L21/763; together with vertical isolation, e.g. trench refilling in a SOI substrate H01L21/76264
• CPC Class Codes: H01L 29/0619 with a supplementary region doped oppositely to or in rectifying contact with the semiconductor containing or contacting region, e.g. guard rings with PN or Schottky junction
• CPC Class Codes: H01L 29/0649 Dielectric regions, e.g. SiO2 regions, air gaps
• CPC Class Codes: H01L 29/0692 Surface layout
• CPC Class Codes: H01L 29/861 Diodes
• CPC Class Codes: H01L 29/872 Schottky diodes

Abstract

A semiconductor diode includes a semiconductor body and trench structures extending from a surface of the semiconductor body into the semiconductor body. The semiconductor body includes a doped layer of a first conductivity type and a doped zone of a second conductivity type opposite to the first conductivity type. The doped zone is formed between the doped layer and a first surface of the semiconductor body. The trench structures are arranged between electrically connected portions of the semiconductor body. The trench structures do not include conductive structures that are both electrically insulated from the semiconductor body and electrically connected with another structure outside the trench structures.

Claims

1. A semiconductor diode, comprising:

a semiconductor body comprising;

a doped layer of a first conductivity type; and

a doped zone of a second conductivity type opposite to the first conductivity type, wherein the doped zone is formed between the doped layer and a first surface of the semiconductor body; and

trench structures extending from one of the first and a second opposing surface into the semiconductor body, the trench structures arranged between electrically connected portions of the semiconductor body, the trench structures not comprising conductive structures that are both electrically insulated from the semiconductor body and electrically connected with another structure outside the trench structures.

2. The semiconductor diode of claim 1, further comprising a metal layer adjoining one of the first and second surfaces.

3. The semiconductor diode of claim 1, wherein the trench structures contain a gaseous fluid.

4. The semiconductor diode of claim 1, wherein the trench structures comprise or consist of one or more dielectric structures.

5. The semiconductor diode of claim 1, wherein the trench structures comprise or consist of a conductive structure directly adjoining the doped zone and forming first portions of a first electrode structure.

6. The semiconductor diode of claim 5, wherein the first electrode structure comprises a second portion directly adjoining the first surface.

7. The semiconductor diode of claim 1, wherein a maximum depth of the trench structures is less than a distance between the first surface and a planar interface between the one or more doped zones and the doped layer, the planar interface being parallel to the first surface.

8. The semiconductor diode of claim 1, further comprising a plurality of doped zones.

9. The semiconductor diode of claim 8, wherein the trench structures are formed between one of the doped zones and an extension portion of the doped layer, respectively, the extension portions adjoining the first surface and formed between the first surface and a contiguous portion of the doped layer, the contiguous portion and the doped zones forming at least in parts planar interfaces parallel to the first surface.

10. The semiconductor diode of claim 9, wherein:

a distance between the at least in parts planar interface and the first surface is greater than a maximum depth of the trench structures; and

the doped zones comprise diffusion portions, each diffusion portion extending around a bottom portion of one of the trench structures, a distance between neighboring diffusion portions being narrower than a distance between trench structures assigned to an intermediate extension portion of the doped layer.

11. The semiconductor diode of claim 1, further comprising a recombination structure at the bottom of the trench structures, respectively, the recombination structures directly adjoining the doped zone, the recombination structure exhibiting a surface recombination rate of at least 10⁴ cm/s at an interface to the doped zone.

12. The semiconductor diode of claim 11, wherein the recombination structure consists of or contains a metal or a conductive metal compound.

13. The semiconductor diode of claim 11, wherein the recombination structure consists of or contains at least one of a material selected from a group containing amorphous semiconductor material, nanocrystalline semiconductor material, microcrystalline semiconductor material, polycrystalline semiconductor material and highly damaged monocrystalline semiconductor material.

14. The semiconductor diode of claim 11, wherein the trench structures comprise a dielectric structure, respectively, each dielectric structure separating the corresponding recombination structure from the semiconductor body in a lateral direction parallel to the first surface.

15. The semiconductor diode of claim 11, wherein the trench structures comprise a fill structure respectively, each fill structure separating the recombination structure from the first surface.

16. The semiconductor diode of claim 11, wherein the doped zone comprises a field stop portion arranged between a buried edge of the trench structures and the doped layer.

17. The semiconductor diode of claim 16, wherein the field stop portion is a contiguous layer forming planar interfaces with the doped zones and the doped layer.

18. The semiconductor diode of claim 16, wherein the field stop portion comprises segments aligned to the trench bottoms and separated from each other.

19. The semiconductor diode of claim 16, wherein the field stop portion is separated from the doped zone.

20. The semiconductor diode of claim 16, wherein the field stop portion has an extension along a direction vertical to the first surface that is larger than the carrier diffusion length in the field stop portion.

21. The semiconductor diode of claim 16, wherein the field stop portion has an extension along a direction vertical to the first surface that is larger than three times the carrier diffusion length in the field stop portion.

22. The semiconductor diode of claim 19, wherein the trench structures are formed between a doped zone and an extension portion of the doped layer, respectively, the extension portion adjoining the first surface and being formed between the first surface and a contiguous portion of the doped layer, the contiguous portion forming interfaces with the doped zones, the interfaces being parallel to the first surface.

23. The semiconductor diode of claim 1, wherein the doped zone is formed in a cell area of the semiconductor body and is absent in an edge area surrounding the cell area, and the trench structures are formed in the cell area.

24. A semiconductor diode, comprising:

a semiconductor body comprising;

a doped layer of a first conductivity type; and

a doped zone of a second conductivity type opposite to the first conductivity type, wherein the doped zone is formed between the doped layer and a first surface of the semiconductor body; and

trench structures extending from one of the first and a second opposing surface into the semiconductor body, the trench structures comprising a recombination structure at the bottom, respectively, the recombination structures directly adjoining the doped zone, the recombination structure exhibiting a surface recombination rate of at least 10⁴ cm/s at an interface to the doped zone.

25. A method of manufacturing a semiconductor diode, the method comprising:

etching trenches from a first surface into a semiconductor body comprising one or more doped zones of a second conductivity type adjoining the first surface and a doped layer of a first conductivity type which is opposite to the second conductivity type, the doped layer forming a planar interface parallel to the first surface;

providing a dielectric structure on sidewalls of the trenches; and

providing a recombination structure at the bottom of each trench.