Semiconductor diode with trench structures and including doped layers and doped zones of opposite conductivity types providing high surge energy capacity

• US 10,069,016 B2
• Filed: 11/20/2014
• Issued: 09/04/2018
• 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
• Primary Examiner(s): Chang, Jay C
• Application Number:
  US14/548,388
• Publication Number:
  US 20150097262A1
• Time in Patent Office: 1,384 Days
• Field of Search: None
• 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 monocrystalline semiconductor body comprising;

a doped layer of a first conductivity type and comprising a continuous portion and extension portions extending from a first surface of the semiconductor body to the continuous portion; and

doped zones forming pn junctions with the continuous portion, wherein the doped zones extend from the first surface to the continuous portion, wherein the doped zones and the extension portions are in direct low-resistive contact with an anode electrode directly formed on the first surface; and

trench structures extending from the first surface into the semiconductor body and horizontally separating the extension portions from base portions of the doped zones, the trench structures (i) not comprising electrically conductive structures or (ii) comprising a recombination structure, a fill structure between the first surface and the recombination structure and a dielectric structure laterally separating the fill structure from the semiconductor body.

2. The semiconductor diode of claim 1, further comprising a metal layer adjoining the first surface.

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 zones 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 doped zones and the doped layer, the planar interface being parallel to the first surface.

8. The semiconductor diode of claim 1, wherein the extension portions adjoin the first surface and the continuous portion and the doped zones form at least in parts planar interfaces parallel to the first surface.

9. The semiconductor diode of claim 8, 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.

10. The semiconductor diode of claim 1, wherein the recombination structure is at a bottom of the trench structures, respectively, the recombination structure directly adjoining the doped zones, the recombination structure exhibiting a surface recombination rate of at least 10⁴ cm/s at an interface to the doped zones.

11. The semiconductor diode of claim 10, wherein the recombination structure consists of or contains a metal or a conductive metal compound.

12. The semiconductor diode of claim 10, 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.

13. The semiconductor diode of claim 10, wherein the dielectric structure separates the corresponding recombination structure from the semiconductor body in a lateral direction parallel to the first surface.

14. The semiconductor diode of claim 10, wherein the fill structure separates the recombination structure from the first surface.

15. The semiconductor diode of claim 10, wherein the doped zones comprise a field stop portion arranged between a buried edge of the trench structures and the doped layer.

16. The semiconductor diode of claim 15, wherein the field stop portion is a contiguous layer forming planar interfaces with the doped zones and the doped layer.

17. The semiconductor diode of claim 15, wherein the field stop portion comprises segments aligned to the trench bottoms and separated from each other.

18. The semiconductor diode of claim 15, wherein the field stop portion is separated from the doped zones.

19. The semiconductor diode of claim 18, wherein the continuous portion forms interfaces with the doped zones, the interfaces being parallel to the first surface.

20. The semiconductor diode of claim 15, wherein the field stop portion has an extension along a direction vertical to the first surface that is larger than a carrier diffusion length in the field stop portion.

21. The semiconductor diode of claim 15, wherein the field stop portion has an extension along a direction vertical to the first surface that is larger than three times a carrier diffusion length in the field stop portion.

22. The semiconductor diode of claim 1, wherein the doped zones are 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.

23. The semiconductor diode of claim 1, wherein the trench structures are spaced at distances from 0.2 to 30 μ

m.

24. The semiconductor diode of claim 1, wherein the fill structure comprises a conductive material without electrical connection to the recombination structure.

25. The semiconductor diode of claim 1, wherein the extension portions comprise contact portions directly adjoining the first surface, wherein a mean dopant concentration in the contact portions is higher than in a portion of the extension portions outside the contact portions.