ESD protection element

• US 9,177,949 B2
• Filed: 09/16/2014
• Issued: 11/03/2015
• 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): Menz, Laura
• Assistant Examiner(s): Malek, Maliheh
• Application Number:
  US14/487,914
• Publication Number:
  US 20150001679A1
• Time in Patent Office: 413 Days
• Field of Search: 257/355, 257/358, 257361-363, 257/577, 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: 1/1
• 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 and an emitter diffusion layer; and

current control resistances provided for a plurality of current paths from a second terminal to said collector diffusion layer through said emitter diffusion layer, respectively,

wherein said bipolar transistor further comprises a base diffusion region connected with said second terminal through a first resistance which is different from said current control resistances,

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.

2. An ESD (Electrostatic Discharge) protection element using a bipolar transistor, comprising:

a first terminal;

a collector region connected with said first terminal;

a second terminal;

a base region;

a first emitter diffusion layer disposed above a surface of said base region;

a second emitter diffusion layer disposed above the surface of said base region;

a first base diffusion layer disposed above the surface of said base region; and

a second base diffusion layer disposed above the surface of said base region,

wherein a first silicide layer is formed on a surface of said first emitter diffusion layer and a surface of said first base diffusion layer,

wherein a first base contact is formed on a surface of said first silicide layer corresponding to a portion straightly above said first base diffusion layer,

wherein said first base contact is connected with said second terminal by a metal interconnection,

wherein a second silicide layer is formed on a surface of said first emitter diffusion layer and a surface of said second base diffusion layer,

wherein a second base contact is formed on a surface of said second silicide layer corresponding to a portion straightly above said second base diffusion layer,

wherein said second base contact is connected with said second terminal by said metal interconnection,

wherein said first emitter diffusion layer and said second emitter diffusion layer are separated in a surface of said base region by an element separation region, and

wherein said first base diffusion layer and said second base diffusion layer are separated in the surface of said base region by said element separation region.

3. The ESD element according to claim 2, wherein said bipolar transistor comprises a first bipolar transistor comprising said first base diffusion layer and said first emitter diffusion layer connected with said second terminal through said first silicide layer,

wherein the ESD element further comprises a second bipolar transistor comprising said second base diffusion layer and said second emitter diffusion layer connected with said second terminal through said second silicide layer, and

wherein said first bipolar transistor and said second bipolar transistor are connected with each other through said collector region.

4. The ESD element according to claim 2, wherein said bipolar transistor includes a vertical NPN bipolar transistor.