Diode structure of a power semiconductor device

Patent metadata

Field	Value
Publication number	US-10340337-B2
Application number	US-201715708180-A
Country	US
Kind code	B2
Filing date	Sep 19, 2017
Priority date	Sep 20, 2016
Publication date	Jul 2, 2019
Grant date	Jul 2, 2019

Abstract

A power semiconductor device includes a semiconductor body coupled to first and second load terminals. The body includes: at least a diode structure configured to conduct a load current between the terminals and including an anode port electrically connected to the first load terminal and a cathode port electrically connected to the second load terminal; and drift and field stop regions of the same conductivity type. The cathode port includes first port sections and second port sections with dopants of the opposite conductivity type. A transition between each of the second port sections and the field stop region forms a respective pn-junction that extends along a first lateral direction. A diffusion voltage of a respective one of the pn-junctions in an extension direction perpendicular to the first lateral direction is greater than a lateral voltage drop laterally overlapping with the lateral extension of the respective pn-junction.

First claim

What is claimed is:

1. A power semiconductor device comprising a semiconductor body coupled to each of a first load terminal and a second load terminal, wherein the semiconductor body comprises:
a drift region with dopants of a first conductivity type;
at least a diode structure configured to conduct a load current between the terminals and comprising an anode port electrically connected to the first load terminal and a cathode port electrically connected to the second load terminal;
a field stop region with dopants of the first conductivity type at a higher dopant concentration than the drift region, the field stop region being arranged between the cathode port and the drift region;
wherein the cathode port comprises:

first port sections with dopants of the first conductivity type and second port sections with dopants of a second conductivity type complementary to the first conductivity type, a transition between each of the second port sections and the field stop region forming a respective pn-junction that extends along a first lateral direction, wherein a diffusion voltage of a respective one of the pn-junctions in an extension direction perpendicular to the first lateral direction is greater than a lateral voltage drop laterally overlapping with the lateral extension of the respective pn-junction.

2. A power semiconductor device comprising a semiconductor body coupled to each of a first load terminal and a second load terminal, wherein the semiconductor body comprises:
a drift region with dopants of a first conductivity type;
at least a diode structure configured to conduct a load current between the terminals and comprising an anode port electrically connected to the first load terminal and a cathode port electrically connected to the second load terminal;
a field stop region with dopants of the first conductivity type at a higher dopant concentration than the drift region, the field stop region being arranged between the cathode port and the drift region;
wherein the cathode port comprises:

first port sections with dopants of the first conductivity type and second port sections with dopants of a second conductivity type complementary to the first conductivity type, a transition between each of the second port sections and the field stop region forming a respective pn-junction that extends along a first lateral direction;
wherein:

the second load terminal comprises a contact area facing the semiconductor body;
in an active region of the power semiconductor device, a percentage share of the contact area laterally overlapping with the second port sections is smaller than a percentage share of the contact area laterally overlapping with the first port sections by a factor of at least two; and
the percentage share of the contact area laterally overlapping with the second port sections increases in a region of the semiconductor body that is laterally adjacent to the active region.

3. The power semiconductor device of claim 1 , wherein the lateral voltage drop is caused by a part of the load current formed by charge carriers of the first conductivity type.

4. The power semiconductor device of claim 1 , wherein the lateral voltage drop occurs over a distance in the first lateral direction amounting to 50% of the total extension of the respective second port section in the first lateral direction.

5. The power semiconductor device of claim 2 , wherein the increase of the percentage share occurs in a transition region arranged in between the diode structure and the adjacent structure.

6. The power semiconductor device of claim 1 , wherein the port sections are arranged laterally and alternately adjacent to each other along the first lateral direction and in electrical contact with the second load terminal.

7. The power semiconductor device of claim 6 , wherein each of transitions between the first port sections and the second load terminal and transitions between the second port sections and the second load terminal form a respective ohmic contact.

8. The power semiconductor device of claim 1 , wherein the first port sections are arranged in electrical contact with the second load terminal, and wherein the second port sections are isolated from the second load terminal by the first port sections.

9. The power semiconductor device of claim 1 , wherein the second port sections have a respective total extension in the first lateral direction smaller than the total extension along the first lateral direction of each of the first port sections.

10. The power semiconductor device of claim 1 , wherein the second port sections have a dopant concentration smaller than the dopant concentration of each of the first port sections.

11. The power semiconductor device of claim 1 , further comprising a transistor structure.

12. The power semiconductor device of claim 11 , wherein each of the second port sections is configured to refrain from emitting charge carries towards the drift region during a turn-off process in the transistor structure.

13. The power semiconductor device of claim 11 , further comprising:
a control electrode structure configured to control operation of the transistor structure; and
a control terminal electrically connected to the control electrode structure by at least a contact runner arranged at least partially external of the semiconductor body,
wherein the transition region laterally overlaps with the contact runner.

14. The power semiconductor device of claim 1 , wherein the second load terminal comprises a contact area facing the semiconductor body, and wherein, in an active region of the power semiconductor device, a percentage share of the contact area laterally overlapping with the second port sections is smaller than a percentage share of the contact area laterally overlapping with the first port sections by a factor of at least two.

15. The power semiconductor device of claim 14 , wherein the percentage share of the contact area laterally overlapping with the second port sections increases along a direction from the diode structure to an adjacent structure of the power semiconductor device, the adjacent structure comprising at least one of an edge structure and a transistor structure.

16. The power semiconductor device of claim 15 , wherein the increase of the percentage share occurs in a transition region arranged in between the diode structure and the adjacent structure.

17. The power semiconductor device of claim 2 , wherein, in the transition region, each of the first port sections and the second port sections has a respective total extension in the first lateral direction of less than 10% of the thickness of semiconductor body.

18. The power semiconductor device of claim 2 , wherein the transition region has a total extension of at least 50% of the thickness of the semiconductor body.

19. The power semiconductor device of claim 1 , wherein, along a path in the extension direction that crosses the field stop region and one of the second port sections, the dopant concentration of the field stop region has a local maximum arranged at a distance to the second port section that amounts to at least 0.5 μm.

20. A method of processing a power semiconductor device, the method comprising:
providing a semiconductor body to be coupled to each of a first load terminal and a second load terminal of the power semiconductor device;
forming, in the semiconductor body:
a drift region with dopants of a first conductivity type;
at least a diode structure configured to conduct a load current between t

Assignees

• Infineon Technologies Ag

Inventors

• Baburske Roman
• Laven Johannes Georg
• Brandt Philip Christoph

Classifications

• H10P32/171

  being group IV material · CPC title

• H10P32/18

  Diffusion lifetime killers · CPC title

• H01L29/1608

  Electricity · mapped topic

• H01L29/66136

  Electricity · mapped topic

• H01L21/221

  Electricity · mapped topic