High-maintaining-voltage SCR structure ESD protection device

Abstract

The utility model discloses a high-maintaining-voltage SCR (Selective Catalytic Reduction) structure ESD (Electro-Static Discharge) protection device, which is characterized in that the high-maintaining-voltage SCR structure ESD protection device comprises a first conductive type substrate. The beneficial effects of the utility model are that the Schottky barrier metal anode is deposited above the second well region of the second conductive type, and the Schottky barrier metal anode and the second well region of the second conductive type form a Schottky barrier; the Schottky barrier is reversely biased and is connected in series with an NPN triode Qn consisting of a second conductive type source region, a first second conductive type well region, a first conductive type substrate and a second second conductive type well region, so that the maintaining voltage of the device when the device is turned on is the sum of the height of the Schottky barrier and the maintaining voltage of the conventional SCR (Selective Catalytic Reduction) maintaining voltage of 1.5-2.5 V; and the protection requirement of the high-speed data transmission interface on the protection device under relatively high working voltage is met.

Description

Technical Field

[0001] This utility model relates to the field of safety protection, specifically a high sustaining voltage SCR structure ESD protection device. Background Technology

[0002] Currently, with the rapid development of communication technology, the demand for high-performance ESD protection devices (Electrostatic Discharge protection devices) for high-speed data ports is increasing daily. With higher requirements for data transmission, the development trend of these protection devices is towards lower capacitance, greater ESD discharge capability, and lower clamping voltage. SCR (Silicon Controlled Rectifier) ​​devices are used for voltage transient and surge protection, offering advantages such as a very small clamping factor, small size, fast response, low leakage current, and high reliability. Thanks to the low holding voltage resulting from the snapback phenomenon, SCR devices consume less power when discharging ESD current, thus their ESD current capability is typically strong, although their secondary breakdown current is relatively large.

[0003] Conventional SCR devices maintain a voltage between 1.5V and 2V when turned on. This low voltage makes these devices prone to latch-up (low impedance path) phenomena, which can easily damage the devices and requires improvement. Utility Model Content

[0004] The purpose of this invention is to provide a high sustaining voltage SCR structure ESD protection device to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] A high sustaining voltage SCR structure ESD protection device includes a first conductivity type substrate, on which a first second conductivity type well region, a first first conductivity type well region, a second second conductivity type well region, and a second first conductivity type well region are sequentially disposed. A second conductivity type source region and a first first conductivity type source region are disposed within the first second conductivity type well region, and the second and first conductivity type source regions together serve as the anode lead-out of the SCR structure device. A Schottky barrier metal anode is disposed above the second second conductivity type well region, and a second first conductivity type source region is disposed within the second first conductivity type well region. The second first conductivity type source region and the Schottky barrier metal anode together serve as the cathode lead-out of the SCR device.

[0007] As a further improvement of this invention, the material of the first conductive type substrate is PSUB.

[0008] As a further improvement of this invention: the Schottky barrier metal anode is a metallic material, including Ni and NiAg alloys.

[0009] As a further embodiment of this invention: the first second conductivity type well region, the second second conductivity type well region, and the second conductivity type source region are all formed by implanting P element. The P element implantation dose of the first second conductivity type well region and the second second conductivity type well region is 1e11~1e18, and the P element implantation dose of the second conductivity type source region is 1e12~1e18.

[0010] As a further embodiment of this utility model: a first first conductivity type well region, a second first conductivity type well region, a first first conductivity type source region, and a second first conductivity type source region are formed by injecting B element, the B element injection dose in the first first conductivity type well region and the second first conductivity type well region is 1e11~1e18, and the B element injection dose in the first first conductivity type source region and the second first conductivity type source region is 1e12~1e18.

[0011] Compared with the prior art, the beneficial effects of this utility model are as follows: In this utility model, a Schottky barrier metal anode is deposited above the second second conductivity type well region to form a Schottky barrier with the second second conductivity type well region. When the SCR is turned on, this Schottky barrier is reverse biased and connected in series with the NPN transistor Qn composed of the second conductivity type source region, the first second conductivity type well region, the first conductivity type substrate, and the second second conductivity type well region. This makes the sustaining voltage when the device is turned on increase by the height of the Schottky barrier on the basis of the conventional SCR sustaining voltage of 1.5V to 2.5V, thus meeting the protection requirements of the high-speed data transmission interface for the protection device under higher operating voltage. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of an ESD protection device with a high sustaining voltage SCR structure.

[0013] Figure 2 This is a structural diagram of a high sustaining voltage SCR structure ESD protection device.

[0014] In the figure: 1-Substrate of first conductivity type, 2-First well region of second conductivity type, 3-Second well region of second conductivity type, 4-First well region of first conductivity type, 5-Second well region of first conductivity type, 6-Source region of second conductivity type, 7-First source region of first conductivity type, 8-Second source region of first conductivity type, 9-Schottky barrier metal anode. Detailed Implementation

[0015] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the protection scope of the present utility model.

[0016] Please see Figure 1 A high sustaining voltage SCR structure ESD protection device includes a first conductivity type substrate 1, and a first second conductivity type well region 2, a first first conductivity type well region 4, a second second conductivity type well region 3, and a second first conductivity type well region 5 sequentially disposed on the first conductivity type substrate 1. A second conductivity type source region 6 and a first first conductivity type source region 7 are disposed within the first second conductivity type well region 2, and the second conductivity type source region 6 and the first first conductivity type source region 7 together serve as the anode lead-out of the SCR structure device. A Schottky barrier metal anode 9 is disposed above the second second conductivity type well region 3, and a second first conductivity type source region 8 is disposed within the second first conductivity type well region 5. The second first conductivity type source region 8 and the Schottky barrier metal anode 9 together serve as the cathode lead-out of the SCR device.

[0017] In this embodiment: Please refer to Figure 1 The material of the first conductivity type substrate 1 is PSUB.

[0018] PSUB stands for P-type semiconductor substrate.

[0019] In this embodiment: Please refer to Figure 1 The Schottky barrier metal anode 9 is a metallic material, including Ni and NiAg alloys.

[0020] The example here is a Ni or NiAg alloy, but in actual use, the material of the Schottky barrier metal anode 9 is not limited.

[0021] In this embodiment: Please refer to Figure 1 The first second-conductivity type well region 2, the second second-conductivity type well region 3, and the second-conductivity type source region 6 are all formed by injecting P element. The P element injection dose of the first second-conductivity type well region 2 and the second second-conductivity type well region 3 is 1e11~1e18, and the P element injection dose of the second-conductivity type source region 6 is 1e12~1e18.

[0022] P element implantation involves N-type doping of intrinsic Si to form an N-type source region, and the implantation dose of P element in fab falls within this range.

[0023] In this embodiment: Please refer to Figure 1The first first conductivity type well region 4, the second first conductivity type well region 5, the first first conductivity type source region 7, and the second first conductivity type source region 8 are formed by injecting B element. The B element injection dose in the first first conductivity type well region 4 and the second first conductivity type well region 5 is 1e11 to 1e18, and the B element injection dose in the first first conductivity type source region 7 and the second first conductivity type source region 8 is 1e12 to 1e18.

[0024] Implanting B involves P-type doping of intrinsic Si to form a P-type source region, and the implantation dose of B in fab falls within this range.

[0025] The working principle of this utility model is as follows: Please refer to... Figure 1 and Figure 2 The main structure of the device is an SCR device formed by coupling an NPN structure Qn consisting of a second conductivity type source region 6, a first second conductivity type well region 2, a first conductivity type substrate 1, and a second second conductivity type well region 3, and a PNP structure Qp consisting of a first first conductivity type source region 7, a first second conductivity type well region 2, a first conductivity type substrate 1, a second first conductivity type well region 5, and a second first conductivity type source region 8. A Schottky barrier metal anode 9 forms a Schottky barrier with the second second conductivity type well region 3. When the SCR is working, a positive potential is applied to the anode of the device. The Schottky barrier metal anode 9 and the second second conductivity type well region 3 form a Schottky diode reverse biased, and are connected in series with the emitter of the NPN structure Qn consisting of the second conductivity type source region 6, the first second conductivity type well region 2, the first conductivity type substrate 1, the first first conductivity type well region 4, and the second second conductivity type well region 3, thus increasing the sustaining voltage of the SCR device. Conventional SCR devices sustain voltages of around 1.5V to 2.5V, which can easily lead to latch-up (low impedance path) in data transmission interface applications with higher operating voltages. This invention integrates a reverse-biased Schottky diode on the emitter of the SCR device to sustain voltages. Based on the conventional SCR structure, the Schottky barrier height can be adjusted according to the process, enabling the SCR device to sustain voltages of over 10V, thus meeting the protection requirements of high-speed data ports at higher operating voltages.

[0026] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects.

[0027] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A high sustaining voltage SCR structure ESD protection device, characterized in that, The high sustaining voltage SCR structure ESD protection device includes a first conductivity type substrate, on which a first second conductivity type well region, a first first conductivity type well region, a second second conductivity type well region, and a second first conductivity type well region are sequentially disposed. A second conductivity type source region and a first first conductivity type source region are disposed within the first second conductivity type well region. The second conductivity type source region and the first first conductivity type source region together serve as the anode lead-out of the SCR structure device. A Schottky barrier metal anode is disposed above the second second conductivity type well region. A second first conductivity type source region is disposed within the second first conductivity type well region. The second first conductivity type source region and the Schottky barrier metal anode together serve as the cathode lead-out of the SCR device.

2. The high sustaining voltage SCR structure ESD protection device according to claim 1, characterized in that, The substrate material for the first conductivity type is PSUB.

3. The high sustaining voltage SCR structure ESD protection device according to claim 1, characterized in that, Schottky barrier metal anodes are made of metallic materials.

4. The high sustaining voltage SCR structure ESD protection device according to claim 1, characterized in that, The first second conductivity type well region, the second second conductivity type well region, and the second conductivity type source region are all formed by injecting P elements.

5. The high sustaining voltage SCR structure ESD protection device according to claim 1 or 4, characterized in that, The first first conductivity type well region, the second first conductivity type well region, the first first conductivity type source region, and the second first conductivity type source region are formed by injecting B elements.

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