Semiconductor device including a diode at least partly arranged in a trench

• US 9,947,648 B2
• Filed: 06/22/2016
• Issued: 04/17/2018
• Est. Priority Date: 12/16/2011
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: Weyers, Joachim, Mauder, Anton, Hirler, Franz, Meiser, Andreas, Glaser, Ulrich
• Primary Examiner(s): Chang, Jay C
• Application Number:
  US15/189,031
• Publication Number:
  US 20160307885A1
• Time in Patent Office: 664 Days
• Field of Search: None
• CPC Class Codes: H01L 27/0255 using diodes as protective elements
• CPC Class Codes: H01L 27/06 including a plurality of individual components in a non-repetitive configuration
• CPC Class Codes: H01L 27/0814 Diodes only
• CPC Class Codes: H01L 29/407 Recessed field plates, e.g. trench field plates, buried field plates
• CPC Class Codes: H01L 29/861 Diodes
• CPC Class Codes: H01L 29/8611 Planar PN junction diodes
• CPC Class Codes: H01L 29/8725 of the trench MOS barrier type [TMBS]

Abstract

A semiconductor device includes a semiconductor body including a first trench extending into the semiconductor body from a first surface and a diode including an anode region and a cathode region. One of the anode region and the cathode region is at least partly arranged in the first trench. The other one of the anode region and the cathode region includes a first semiconductor region directly adjoining the one of the anode region and the cathode region from outside of the first trench, thereby constituting a pn junction. The semiconductor device further includes a conducting path through a sidewall of the first trench.

Claims

1. A semiconductor device, comprising:

a semiconductor body including a first trench extending into the semiconductor body from a first surface of the semiconductor body;

a diode including an anode region and a cathode region, wherein one of the anode region and the cathode region is at least partly arranged in the first trench, wherein the other one of the anode region and the cathode region includes a first semiconductor region directly adjoining the one of the anode region and the cathode region from outside of the first trench, thereby constituting a pn-junction in the semiconductor body and extending to the first surface; and

a conducting path of the diode through a sidewall of the first trench, and wherein the pn-junction extends along at least 50% of a depth of the first trench.

2. The semiconductor device of claim 1, further comprising a second trench at a lateral distance to the first trench and extending into the semiconductor body from the first surface, wherein the other one of the anode region and the cathode region is arranged at least partly in the second trench.

3. The semiconductor device of claim 1, wherein a direction of electrical breakdown current between the anode region and the cathode region is a lateral direction parallel to the first surface.

4. The semiconductor device of claim 1, wherein the diode includes a positive differential resistance of less than 20 mΩ

×

mm² at a breakdown voltage V_br>

20V and at a temperature T=423K for a whole breakdown current range of 0.1 to 10 A/mm².

5. The semiconductor device of claim 1, wherein at least one of the anode region and the cathode region is electrically connected with a pin.

6. The semiconductor device of claim 1, wherein:

the first semiconductor region is of a first conductivity type; and

the one of the anode region and the cathode region includes a second semiconductor region of a second conductivity type opposite the first conductivity type.

7. The semiconductor device of claim 6, wherein the second semiconductor region includes doped polysilicon.

8. The semiconductor device of claim 6, wherein the first trench region is filled with the second semiconductor region.

9. The semiconductor device of claim 6, wherein a first part of the second semiconductor region, at least one of a dielectric and a metal structure and a second part of the second semiconductor region are arranged in this order along a lateral direction parallel to the first surface.

10. The semiconductor device of claim 1, further comprising:

a first contact area to the one of the anode region and the cathode region arranged on the first surface; and

a second contact area to the other one of the anode region and the cathode region arranged on a second surface of the semiconductor body opposite the first surface.

11. The semiconductor device of claim 10, wherein:

the first contact area is electrically coupled to the one of the anode region and the cathode region at a top side of the one of the anode region and the cathode region; and

the second contact area is electrically coupled to the other one of the anode region and the cathode region at a bottom side of the other one of the anode region and the cathode region.

12. The semiconductor device of claim 1, further comprising:

a first contact area to the one of the anode region and the cathode region arranged on the first surface; and

a second contact area to the other one of the anode region and the cathode region arranged on the first surface.

13. The semiconductor device of claim 1, further comprising:

a buried layer adjoining a bottom side of the first semiconductor region, the buried layer including a concentration of dopants that is larger than a concentration of dopants of the first semiconductor region,

wherein the buried layer and the first semiconductor region have the same conductivity type.

14. The semiconductor device of claim 1, wherein the diode is a Schottky diode and the one of the anode region and the cathode region is a Schottky contact material arranged in the first trench.

15. The semiconductor device of claim 1, further comprising a shallow trench isolation at the first surface in an area of the first semiconductor region.

16. The semiconductor device of claim 1, wherein a lateral width of the first trench region is larger in a bottom part of the first trench region than in a top part of the first trench region.

17. The semiconductor device of claim 1, further comprising an isolating layer at a bottom side of the first trench.

18. The semiconductor device of claim 1, further comprising:

a semiconductor substrate; and

a p-doped semiconductor layer on the semiconductor substrate,

wherein the first semiconductor region is arranged in the p-doped semiconductor layer.

19. The semiconductor device of claim 1, further comprising a functional element, and wherein the diode covers an area at the first surface in a range between 1000 μ

m² and 1 mm² and is configured to protect the functional element against ESD (electrostatic discharge).

20. The semiconductor device of claim 1, further comprising a semiconductor element, and wherein the diode is a clamping diode configured to clamp a voltage between two terminals of the semiconductor element.

21. The semiconductor device of claim 1, wherein the first semiconductor region extends parallel to a sidewall of the first trench, thereby constituting the pn junction.

22. A semiconductor device, comprising:

a semiconductor body including a first trench region extending into the semiconductor body from a first surface of the semiconductor body;

a diode including an anode region and a cathode region, wherein one of the anode region and the cathode region is at least partly arranged in the first trench region, and wherein the other one of the anode region and the cathode region includes a first semiconductor region adjoining the one of the anode region and the cathode region from outside of the first trench region;

a field plate arranged on the first surface, the field plate overlapping a pn-junction comprising a p-doped region of the anode region abutting an n-doped region of the cathode region at the first surface; and

a contact at the first surface and electrically connected to the one of the anode region and the cathode region at the first surface,

wherein the field plate and the contact are electrically connected.

23. The semiconductor device of claim 22, further comprising an insulating layer arranged between and abutting the pn-junction at the first surface and the field plate.

24. The semiconductor device of claim 22, further comprising:

a second trench region extending into the semiconductor body from the first surface,

wherein the other one of the anode region and the cathode region is arranged at least partly in the second trench region.

25. The semiconductor device of claim 24, wherein a first depth of the first trench region differs from a second depth of the second trench region.

26. The semiconductor device of claim 24, wherein the second trench region surrounds the first trench region at the first surface.

27. The semiconductor device of claim 24, wherein the first and second trench regions are arranged parallel to each other along the first surface.

28. The semiconductor device of claim 24, further comprising:

a plurality of the first trenches and a plurality of the second trenches,

wherein a lateral distance between one of the first trenches and a neighboring one of the second trenches differs from a lateral distance between another one of the first trenches and another neighboring one of the second trenches.

29. The semiconductor device of claim 22, wherein the one of the anode region and the cathode region is a first electrode region arranged in the first trench region, the semiconductor device further comprising a second electrode region arranged in a second trench region.

30. The semiconductor device of claim 29, wherein:

the first electrode region is electrically connected to a first pin; and

the second electrode region is electrically connected to a second pin different from the first pin.