ESD protection element

• US 8,860,139 B2
• Filed: 03/11/2010
• Issued: 10/14/2014
• Est. Priority Date: 03/11/2009
• Status: Active Grant

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: Renesas Electronics Corporation
• Inventors: Sawahata, Kouichi
• Primary Examiner(s): Kraig, William F
• Assistant Examiner(s): Malek, Maliheh
• Application Number:
  US12/722,000
• Publication Number:
  US 20100230719A1
• Time in Patent Office: 1,678 Days
• Field of Search: 257/355, 257/358, 257361-363, 257/539, 257/542, 257/565, 257/566, 257574-577, 257579-582, 257/E31.069, 257/E27.037, 257/E27.043, 257/E27.106, 257E2903-E29031, 257/E29.034, 257E29044-E29045, 438/309, 438/314, 438322-327, 438330-332, 438/340
• US Class Current: 257/355
• CPC Class Codes: H01L 27/0248 for electrical or thermal protection, e.g. electrostatic discharge [ESD] protection
• CPC Class Codes: H01L 27/0259 using bipolar transistors as protective elements
• CPC Class Codes: H01L 27/0292 using a specific configuration of the conducting means connecting the protective devices, e.g. ESD buses
• CPC Class Codes: H01L 27/0658 Vertical bipolar transistor in combination with resistors or capacitors
• CPC Class Codes: H01L 29/0615 by the doping profile or the shape or the arrangement of the PN junction, or with supplementary regions, e.g. junction termination extension [JTE] LDD or drain offset regions H01L29/7833
• CPC Class Codes: H01L 29/0808 of lateral transistors
• CPC Class Codes: H01L 29/0813 Non-interconnected multi-emitter structures
• CPC Class Codes: H01L 29/0821 Collector regions of bipolar transistors
• CPC Class Codes: H01L 29/1008 of lateral transistors
• CPC Class Codes: H01L 29/7304 the device being a resistive element, e.g. ballasting resistor transistors integrated with resistors H01L27/075
• CPC Class Codes: H01L 29/735 Lateral transistors
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

In an aspect of the present invention, an ESD (Electrostatic Discharge) protection element includes a bipolar transistor comprising a collector diffusion layer connected with a first terminal and an emitter diffusion layer; and current control resistances provided for a plurality of current paths from a second terminal to the collector diffusion layer through the emitter diffusion layer, respectively. The bipolar transistor further includes a base diffusion region connected with the second terminal through a first resistance which is different from the current control resistances.

Claims

1. An ESD (Electrostatic Discharge) protection element comprising:

a bipolar transistor comprising;

a collector diffusion layer connected with a first terminal;

a base diffusion layer; and

an emitter diffusion layer;

a first wire connected to the emitter diffusion layer and the base diffusion layer;

a second wire connected to the emitter diffusion layer and the base diffusion layer;

a first current control resistance connected to a second terminal, and connected to the first wire by a first contact;

a second current control resistance connected to the second terminal, and connected to the second wire by a second contact,

wherein the collector diffusion layer and the emitter diffusion layer are each arranged in a base width direction,

the first and second wires and the first and second current control resistances are each arranged in a direction that is perpendicular to the base width direction, and

wherein current flowing out to a power supply voltage is distributed to flow through the first and second current control resistances in order to reduce current concentration in a breakdown path.

2. The ESD protection element according to claim 1, wherein the base diffusion layer of said bipolar transistor is connected with said second terminal through a first resistance which is different from said first and second current control resistances.

3. The ESD protection element according to claim 2, wherein said emitter diffusion layer further comprises a plurality of third contacts connected with said second terminal through said first and second current control resistances, respectively, and

said base diffusion layer further comprises a plurality of fourth contacts connected with said second terminal through a plurality of said first resistances.

4. The ESD protection element according to claim 1, wherein the base diffusion layer is connected with said second terminal through said first and second current control resistances, respectively.

5. The ESD protection element according to claim 4, wherein said emitter diffusion layer has a plurality of third contacts connected with said second terminal through said first and second current control resistances, respectively, and

wherein said base diffusion layer has a plurality of fourth contacts connected with said second terminal through said first and second current control resistances, respectively.

6. The ESD protection element according to claim 2, wherein said emitter diffusion layer comprises a plurality of emitter diffusion sub layers, in each of which at least one contact is formed.

7. The ESD protection element according to claim 6, wherein said base diffusion layer comprises a plurality of base diffusion sub layers, in each of which at least one contact is formed.

8. The ESD protection element according to claim 6, wherein said base diffusion layer is partially separated in a base width direction by an element separation region.

9. The ESD protection element according to claim 7, wherein said emitter diffusion layer and said base diffusion layer are in contact with each other.

10. The ESD protection element according to claim 7, wherein said plurality of emitter diffusion sub layers are connected with said plurality of base diffusion sub layers through a plurality of wirings, respectively, the plurality of wirings including the first and second wires.

11. The ESD protection element according to claim 1, wherein said first and second current control resistances are formed from resistance components of said emitter diffusion layer.

12. The ESD protection element according to claim 1, further comprising a silicide film formed on said emitter diffusion layer,

wherein said current adjustment, and

wherein said first and second current control resistances are formed from resistance components of said silicide film.

13. The ESD protection element according to claim 11, wherein at least a part of said emitter diffusion layer is separated in a base width direction by an element separation region.

14. The ESD protection element according to claim 11, wherein said bipolar transistor further comprises a base diffusion layer connected with said second terminal through a second contact,

wherein said emitter diffusion layer is provided between said base diffusion layer and said collector diffusion layer,

wherein said base diffusion layer and said emitter diffusion layer are adjacent to each other in a direction perpendicular to the base width direction, and

wherein a length of said emitter diffusion layer from an end thereof on a side of said collector diffusion layer to an end thereof on a side of said base diffusion layer is set to a predetermined length.

15. The ESD protection element according to claim 14, wherein said emitter diffusion layer has a third contact configured to connect said emitter diffusion layer and said second terminal, and

wherein said third contact is formed on an end of said emitter diffusion layer on a side of said fourth contact.

16. The ESD element protection element according to claim 15, wherein a first bipolar transistor comprises a first emitter diffusion layer and a first base diffusion layer which are connected with said first terminal in common through a first current control resistance;

and

a second bipolar transistor comprises a second emitter diffusion layer and a second base diffusion layer which are connected with said second terminal in common through a second current control resistance,

wherein said first bipolar transistor and said second bipolar transistor are connected through a collector region,

wherein said first current control resistance is provided for a plurality of current paths from said first terminal to said collector region through said first emitter diffusion layer, and

wherein said second current control resistance is provided for a plurality of current paths from said second terminal to said collector region through said first emitter diffusion layer.

17. The ESD protection element according to claim 16, wherein said bipolar transistor is a vertical-type NPN bipolar transistor.

28. The ESD protection element according to claim 1, further comprising a common wiring connected to each of the first and second current control resistances and the second terminal.

29. The ESD protection element according to claim 28, wherein the common wiring distributes a current to each of the first and second current control resistances, in response to the current flowing to the second terminal.

18. An ESD (Electrostatic Discharge) protection element comprising:

a bipolar transistor comprising;

a collector diffusion region connected with a first terminal;

a base diffusion region; and

an emitter diffusion region;

a first wire connected to the emitter diffusion region and the base diffusion region;

a second wire connected to the emitter diffusion region and the base diffusion region;

a first current control resistance connected to a second terminal, and connected to the first wire by a first contact;

a second current control resistance connected to the second terminal, and connected to the second wire by a second contact,

wherein the first and second wires each provide a separate current path from the second terminal to the collector diffusion layer through the emitter layer, and

wherein current flowing out to a power supply voltage is distributed to flow through the first and second control resistances in order to reduce current concentration in a breakdown path.

19. The ESD protection element according to claim 18, wherein the base diffusion region is connected with said second terminal through a base resistance which is different from said first and second current control resistances.

20. The ESD protection element according to claim 18, wherein a plurality of third contacts is provided for said emitter diffusion region to be connected with said second terminal through said of first and second current control resistances, respectively.

21. The ESD protection element according to claim 20, wherein a plurality of fourth contacts is provided for said base diffusion region to be connected with said second terminal through said first second current control resistances, respectively.

22. The ESD protection element according to claim 18, wherein said emitter diffusion region comprises a plurality of emitter diffusion subregions which are respectively connected with said second terminal through said first and second current control resistances.

23. The ESD protection element according to claim 22, wherein a plurality of fourth contacts is provided for said base diffusion region to be connected with said second terminal through said first and second current control resistances, respectively.

24. The ESD protection element according to claim 22, wherein said base diffusion region comprises a plurality of base diffusion subregions which are respectively connected with said second terminal through base resistances.

25. The ESD protection element according to claim 24, wherein said first and second current control resistances are resistance components of said plurality of emitter diffusion subregions, respectively.

26. The ESD protection element according to claim 24, further comprising:

a base region layer extending from a portion under said base diffusion region to a portion under said emitter diffusion region; and

wherein said base resistances are resistance components of said base region layer.

27. The ESD protection element according to claim 24, further comprising:

a plurality of silicide films, each of which is formed on one of said plurality of emitter diffusion subregions and a corresponding one of said a plurality of base diffusion subregions; and

a base region layer extending from a portion under said base diffusion region to a portion under said emitter diffusion region,

wherein said first and second current control resistances are resistance components of said plurality of silicide films, and

wherein said base resistances are resistance components of said base region layer.

30. An ESD (Electrostatic Discharge) protection element comprising:

a bipolar transistor comprising;

a collector diffusion layer connected with a first terminal;

a base diffusion layer; and

an emitter diffusion layer;

a plurality of wires each connected to the emitter diffusion layer and the base diffusion layer; and

a plurality of current control resistances each of which is connected to a second terminal and a respective wire of the plurality of wires,

wherein the collector diffusion layer and the emitter diffusion layer are each arranged in a base width direction,

the plurality of wires and the plurality of current control resistances are each arranged in a direction that is perpendicular to the base width direction, and

wherein current flowing out to a power supply voltage is distributed to flow through the plurality of current control resistances in order to reduce current concentration in breakdown path.