Monolithic semiconductor device and method of manufacturing same

• US 4,860,072 A
• Filed: 03/10/1988
• Issued: 08/22/1989
• Est. Priority Date: 03/05/1986
• Status: Expired due to Term

• Current Assignee: IXYS Corporation (Littelfuse Incorporated)
• Original Assignee: IXYS Corporation (Littelfuse Incorporated)
• Inventors: Zommer, Nathan
• Primary Examiner(s): Wojciechowicz, Edward J.
• Application Number:
  US07/166,809
• Time in Patent Office: 530 Days
• Field of Search: 357/23.4, 357/23.8, 357/41, 357/43, 357/55, 357/86
• US Class Current: 257/144
• CPC Class Codes: H01L 29/0696 of cellular field-effect devices, e.g. multicellular DMOS transistors or IGBTs
• CPC Class Codes: H01L 29/7395 Vertical transistors, e.g. vertical IGBT

Abstract

A monolithic semiconductor device for use in various applications such as lateral and vertical MOS transistors, insulated gate conductivity modulated devices and the like together with a method of manufacturing same. The device includes source, body and drain regions, with the body region including a channel section which is disposed adjacent an insulated gate formed on the surface of the device. The source region includes a central contact area flanked by a pair of body segments which extend up through the source region and which create a resistive path between the source contact area and the channel section. A voltage is developed across the resistive path which tends to maintain a parasitic bipolar transistor formed by the source, body and drain regions in a non-conductive state. A source metallization bridges the two body segments and the intermediate source contact thereby shorting the body region to the source. The geometry of the device is reduced in that width of the source contact area need not be increased to ensure that the source metallization contacts both the source and the body region.

Claims

1. A monolithic semiconductor device comprising:

a semiconductor body having a first major surface;

a contiguous first region disposed in said semiconductor body of a first conductivity type, said first region including a channel section abutting said first surface, a first intermediate section spaced apart from said channel section and abutting said first surface and a body section disposed below said first surface and interconnecting said channel and said first intermediate sections;

a contiguous second region disposed in said semiconductor body of a second conductivity type, opposite of said first conductivity type, said second region being bounded by said first region and including a peripheral section between said channel section and said first intermediate section, above said body section and abutting said first surface, a contact section abutting said first surface, and spaced part from said peripheral section, with said peripheral section and said contact section being disposed on opposite sides of said first intermediate section and interconnected by other first portions of said second region;

an insulating layer positioned over said channel section on said first surface;

a first electrode on said insulating layer above said channel section; and

a first ohmic contact on said contact section so that at least part of current flow between said contact section and said peripheral section is around said first intermediate section and through said other first portions of said second region.

2. The semiconductor device of claim 1 further including a third region disposed in said semiconductor body of said second conductivity type which bounds said first region, said third region including a drift section adjacent said channel section, opposite said peripheral section.

3. The semiconductor device of claim 2 further including a second ohmic contact on said third region.

4. The semiconductor device of claim 3 wherein said third region includes a contact section abutting said first major surface, with said second ohmic contact disposed at said third region contact section.

5. The semiconductor device of claim 3 wherein said semiconductor body includes a second major surface, generally parallel to said first major surface, and wherein said third region includes a contact section abutting said second surface, with said second ohmic contact being disposed at said third region contact section.

6. The semiconductor device of claim 3 wherein said channel section of said first region and said peripheral section of said second region both extend around said contact section of said second region, with said first region further including a second intermediate section spaced apart from said first intermediate section and abutting said first surface between said peripheral section and said contact section of said second region, with other second portions of said second region interconnecting said contact section and said peripheral section so that at least part of current flow between said contact section and said peripheral section is around said second intermediate section and through said other second portions of said second region.

7. The semiconductor device of claim 6 wherein said first and second intermediate sections are disposed on opposite sides of said contact section of said second region.

8. The semiconductor device of claim 7 wherein said first and second conductivity types are P and N type, respectively.

9. The semiconductor device of claim 8 wherein said semiconductor body is comprised of a semiconductor substrate with an expitaxial layer on said substrate abutting said first major surfaces, with said first and second regions being disposed in said expitaxial layer.

10. The semiconductor device of claim 9 wherein said expitaxial layer is N type

11. The semiconductor device of claim 10 wherein said first electrode is polysilicon.

12. The semiconductor device of claim 11 wherein said device functions as a MOS transistor, with said first electrode functioning as a gate, said first ohmic contact including a second electrode which functions as a source and said second ohmic contact including a third electrode which functions as a drain.

13. The semiconductor device of claim 2 wherein said semiconductor device has a second major surface, generally parallel to said first major surface, and said semiconductor device further includes a fourth region disposed in said semiconductor body intermediate said third region and said second major surface, said fourth region being of said first conductivity type and including a contact section abutting said second major surface and a second ohmic contact disposed at said fourth region contact section.

14. The semiconductor device of claim 13 wherein said channel and peripheral sections both extend around said second region contact section, with said first region further including a second intermediate section spaced apart from said first intermediate section and abutting said first major surface between said peripheral section and said second region contact section, with other second portions of said second region interconnecting said second region contact section and said peripheral section so that at least part of current flow between said second region contact section and said peripheral section is around said second intermediate section and through said other second portions of said second region.

15. The semiconductor device of claim 14 wherein said device functions as an insulated gate conductivity modulated device, with said first and second conductivity types being of type P and N, respectively, said first electrode functioning as a gate, said first ohmic contact including a second electrode functioning as a cathode and said second ohmic contact including a third electrode functioning as an anode.

16. The semiconductor device of claim 15 wherein said first electrode in polysilicon.

17. The semiconductor device of claim 16 wherein said first and second intermediate sections of said first region are disposed on opposite sides of said second region contact section.

26. The semiconductor device of claim 12 wherein said second electrode extends between said first and second intermediate sections and over said contact section of said second region so as to electrically interconnect said first and second intermediate sections and said second region contact section at said first surface.

27. The semiconductor device of claim 17 wherein said second electrode extends between said first and second intermediate sections and over said second region contact section so as to electrically interconnect said first and second intermediate sections and said second region contact section at said first surface.

18. A monolithic semiconductor device comprising:

a semiconductor body having generally parallel first and second major surfaces and an expitaxial layer of a first conductivity type which abuts said first major surface;

a first contiguous region of a second conductivity type, disposed in said expitaxial layer, opposite of said first conductivity type, said first region including a channel section which extends around the periphery of said first region and abuts said first major surface and first and second intermediate sections, spaced apart from said channel section and one another and which abut said first major surface and a body section disposed below said first surface and interconnecting said channel with said first and intermediate sections;

a second contiguous region of said first conductivity type and bounded by said first region, said second region including a peripheral section and a contact section abutting said first major surface, with said peripheral section being disposed adjacent said channel section, extending around said contact section and above said body section, said contact section being disposed between said first and second intermediate sections and said contact section and said peripheral section being interconnected by other portions of said second region;

a third region of said first conductivity type which bounds said first region, said third region including a drift section, adjacent said channel section and opposite said peripheral section;

an insulating layer positioned over said channel section on said first major surface;

a first electrode on said insulating layer positioned over said channel section; and

a first ohmic contact on said second region contact section so that at least a part of the current flow between said second region contact section and said peripheral section is around said first and second intermediate sections and through said other portions of said second region.

19. The semiconductor device of claim 18 wherein said third region includes a contact section abutting said first major surface and a second ohmic contact on said contact section.

20. The semiconductor device of claim 19 wherein said device functions as a lateral MOS transistor, said first and second conductivity types are N and P, respectively, and said first electrode functions as a gate, said first ohmic contact includes a second electrode which functions as a source and said second ohmic contact includes a third electrode which functions as a drain.

21. The semiconductor device of claim 20 wherein said first electrode is polysilicon.

22. The semiconductor device of claim 18 wherein said third region includes a contact section abutting said second major surface and a second ohmic contact on said contact section.

23. The semiconductor device of claim 22 wherein said device functions as a vertical MOS transistor, said first and second conductivity types are N and P, respectively, and said first electrode functions as a gate, said first ohmic contact includes a second electrode which functions as a source and said second ohmic contact includes a third electrode which functions as a drain.

24. The semiconductor device of claim 18 further including a fourth region of said second conductivity type disposed between said third region and said second major surface, said fourth region including a contact section abutting said second major surface and a second ohmic contact on said contact section.

25. The semiconductor device of claim 24 wherein said device functions as an insulated gate conductivity modulated device with said first and second conductivity types being type N and P, respectively, said first electrode functioning as a gate, said first ohmic contact including a second electrode which functions as a cathode and said second ohmic contact includes a third electrode which functions as an anode.

28. The semiconductor device of claim 20 wherein said second electrode extends between said first and second intermediate sections and over said contact section of said second region so as to electrically interconnect said first and second intermediate sections and said second region contact section at said first surface.

29. The semiconductor device of claim 23 wherein said second electrode extends between said first and second intermediate sections over said contact section of said second region so as to electrically interconnect said first and second intermediate sections and said second region contact section at said first surface.

30. The semiconductor device of claim 25 wherein said second electrode extends between said first and second intermediate sections over said contact section of said second region so as to electrically interconnect said first and second intermediate sections and said second region contact section at said first surface.