ELECTROSTATIC DISCHARGE DEVICE

• US 20170236816A1
• Filed: 02/17/2016
• Published: 08/17/2017
• Est. Priority Date: 02/17/2016
• Status: Active Grant

• Current Assignee: Macronix International Co., Ltd.
• Original Assignee: Macronix International Co., Ltd.
• Inventors: TSAI, Ying-Chieh, CHAN, Wing-Chor
• Granted Patent: US 9,786,651 B2
• Time in Patent Office: Days
• CPC Class Codes: H01L 27/0255 using diodes as protective elements
• CPC Class Codes: H01L 27/0259 using bipolar transistors as protective elements
• CPC Class Codes: H01L 27/0262 including a PNP transistor and a NPN transistor, wherein each of said transistors has its base coupled to the collector of the other transistor, e.g. silicon controlled rectifier [SCR] devices
• 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 29/0603 characterised by particular constructional design considerations, e.g. for preventing surface leakage, for controlling electric field concentration or for internal isolations regions isolation regions between components H01L21/76; design considerations for integrated circuits H01L27/00; geometrical design considerations for devices H01L29/0657
• CPC Class Codes: H01L 29/0649 Dielectric regions, e.g. SiO2 regions, air gaps
• CPC Class Codes: H01L 29/861 Diodes
• CPC Class Codes: H01L 29/866 Zener diodes
• CPC Class Codes: H01L 29/87 Thyristor diodes, e.g. Shockley diodes, break-over diodes

Abstract

An electrostatic discharge device includes a power clamping circuit and an isolation circuit. The power clamping circuit includes a first Zener diode and a second Zener diode. A cathode of the first Zener diode is coupled to a first power supply line. An anode of the first Zener diode is coupled to an anode of the second Zener diode. A cathode of the second Zener diode is coupled to a second power supply line. The isolation circuit includes a first isolation diode and a second isolation diode. A cathode of the first isolation diode is coupled to the first power supply line. An anode of the first isolation diode is coupled to a cathode of the second isolation diode and a circuit being protected. An anode of the second isolation diode is coupled to the second power supply line.

Claims

1. An electrostatic discharge (ESD) device, comprising:

a power clamping circuit including a first Zener diode and a second Zener diode, a cathode of the first Zener diode being coupled to a first power supply line, an anode of the first Zener diode being coupled to an anode of the second Zener diode, and a cathode of the second Zener diode being coupled to a second power supply line; and

an isolation circuit including a first isolation diode and a second isolation diode, a cathode of the first isolation diode being coupled to the first power supply line, an anode of the first isolation diode being coupled to a cathode of the second isolation diode and a circuit being protected, and an anode of the second isolation diode being coupled to the second power supply line,

wherein at least one of the first or second isolation diode includes

a P-type well formed in a substrate;

an N-type well formed in the P-type well; and

an N-type region formed in the P-type well in contact with a partial portion of the bottom of the first N-type well, the N-type region having a higher doping concentration than the first N-type well.

2. The ESD device of claim 1, wherein the power clamping circuit includes:

a P-type well formed in a semiconductor substrate;

a first N-type region and a second N-type region formed in the P-type well, the first and second N-type regions sandwiching a portion of the P-type well, the first Zener diode including the first N-type region and the portion of the P-type well, and the second Zener diode including the second N-type region and the portion of the P-type well.

3. The ESD device of claim 2, wherein the power clamping circuit further includes:

a first P-type region formed in the P-type well and below the first N-type region; and

a second P-type region formed in the P-type well and below the second N-type region,

the first and second N-type regions, the first and second P-type regions, and the P-type well forming a parasitic NPN bipolar-junction transistor structure.

4. The ESD protection device of claim 1, wherein the N-type well is a first N-type well, at least one of the first or second isolation diode further including:

a second N-type well formed in the P-type well, the first and second N-type wells sandwiching a common P region in the P-type well; and

a heavily-doped P-type (P⁺) region formed over the first N-type well and a heavily-doped N-type (N⁺) region formed over the second N-type well.

5. The ESD protection device of claim 4, wherein a distance between the first N-type well and the second N-type well is about 0.2 μ

m to about 5 μ

m.

6. The ESD protection device of claim 4, wherein:

the N⁺ region is a first N⁺ region, and

the at least one of the first or second isolation diode further includes a second N⁺ region formed in the P⁺ region, the second N⁺ region and the P⁺ region being coupled to each other by a wiring.

7-10. -10. (canceled)