A shallow-scan bidirectional TVS structure

Abstract

The present application relates to the technical field of electrostatic protection and surge suppression, and particularly relates to a shallow-scan bidirectional TVS structure, which comprises: a substrate layer, which is a P-type lightly doped Si material, i.e. a P-type substrate; an Nwell1 region, which is formed on the P-type substrate and has an N-type conductivity; an Nwell2 region, which is formed on the P-type substrate and has an N-type conductivity; an N1 region, which is formed in the Nwell1 region and has an N-type conductivity; a P1 region, which is formed in the Nwell1 region and has a P-type conductivity; an N2 region, which is formed in the Nwell2 region and has an N-type conductivity; a P2 region, which is formed in the Nwell2 region and has a P-type conductivity; a dielectric layer, which is formed on the upper surface of the P-type substrate; and a metal electrode layer, which realizes the connection of P1 and P2 through metal wiring, and the N1 metal leading-out electrode is I / O1 and the N2 metal leading-out electrode is I / O2. The integration of the low-voltage TVS device and the NPN structure reduces the integration difficulty, realizes the process simply, has good bidirectional voltage symmetry, and significantly improves the overall performance.

Description

Technical Field

[0001] This invention relates to the field of electrostatic discharge protection and surge suppression technology. In high-speed communication and power ports, it can reduce high impedance to low impedance at an extremely high speed during instantaneous high-energy surges, thereby absorbing large currents. It is widely used in protection circuits for USB 2.0 / 3.0, HDMI 1.3 / 1.4 / 2.0, Type-C, CAN bus, etc., and particularly relates to a shallow retrace bidirectional TVS structure. Background Technology

[0002] With the advancement of technology, new technologies such as clean energy, automotive electronics, 5G communications, and digital technologies are driving revolutionary changes in the electronics and power industry, which is also steadily developing in response to people's growing needs. Transient voltage suppressor (TVS) diodes are safety components in various circuit systems, and the rapid development of the electronics and power industry will drive market demand for TVS diodes. In the future, electronic products will develop towards miniaturization, low voltage, low power consumption, and high frequency, which requires corresponding protection devices to develop towards low clamping voltage and low capacitance.

[0003] Currently, the most commonly used shallow-followback bidirectional TVS structures generally employ a vertical NPN structure or a combination of vertical NPN and TVS devices. The main problems with this approach are that a pure NPN structure suffers from bidirectional voltage asymmetry and difficulty in controlling the flyback voltage. The combination of vertical NPN and TVS devices, on the other hand, presents challenges in integration and complex manufacturing processes. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention discloses a shallow-sweep bidirectional TVS structure and device. Through the design and research of the lateral structure, this invention integrates a low-voltage TVS device with an NPN structure, thereby reducing integration difficulty, simplifying process implementation, improving bidirectional voltage symmetry, and significantly improving overall performance.

[0005] This invention is achieved through the following technical solution:

[0006] A shallow retrace bidirectional TVS structure, the bidirectional TVS structure comprising:

[0007] The substrate is a lightly doped Si material of type P, i.e., a P-type substrate.

[0008] The Nwell1 region is formed on a P-type substrate and has an N-type conductivity.

[0009] The Nwell2 region is formed on a P-type substrate and has an N-type conductivity.

[0010] The N1 region is formed in the Nwell1 region and has an N-type conductivity.

[0011] The P1 region is formed in the Nwell1 region and has a P-type conductivity.

[0012] The N2 region is formed in the Nwell2 region and has an N-type conductivity.

[0013] The P2 region is formed in the Nwell2 region and has a P-type conductivity.

[0014] A dielectric layer is formed on the upper surface of a P-type substrate;

[0015] The metal electrode layer connects P1 and P2 through metal wiring. The N1 metal lead-out electrode is I / O1, and the N2 metal lead-out electrode is I / O2.

[0016] Preferably, the substrate material is a P-type silicon material with a resistivity between 500-2000 ohm·cm, and the doping element is boron.

[0017] Preferably, Nwell1 and Nwell2 regions are formed on the front side of the P-type substrate by implanting arsenic or phosphorus, with an implantation dose of 1.0E13-5.0E14 and a diffusion temperature of 900℃-1100℃.

[0018] Preferably, N1 and N2 regions are formed on the front sides of the Nwell1 and Nwell2 regions by implanting elemental arsenic or phosphorus, respectively, with an implantation dose of 1.0E15-1.0E16 and a diffusion temperature of 900℃-1100℃.

[0019] Preferably, P1 and P2 regions are formed on the front sides of the Nwell1 and Nwell2 regions respectively by implanting elemental boron, with an implantation dose of 1.0E15-1.0E16 and a diffusion temperature of 900℃-1100℃.

[0020] Preferably, the dielectric layer is silicon dioxide or a combination of silicon dioxide and silicon nitride.

[0021] Preferably, the metal in the metal electrode layer is a conductive material, using AlSiCu, Al, or Ag as the electrode metal, and the metal forming the ohmic contact layer is Ti or Ti / TiN, with a metal thickness between 3µm and 6µm.

[0022] The present invention has the following beneficial effects:

[0023] This invention is used to realize a bidirectional TVS product with shallow flyback. Through the design and research of the lateral structure, the low-voltage TVS device is integrated with the NPN structure, which reduces the integration difficulty, simplifies the process, improves the bidirectional voltage symmetry, and significantly improves the overall performance. The surge current discharge uses the NPN structure with shallow flyback, which can effectively reduce the clamping voltage and prevent latch-up effect. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a cross-sectional view of an embodiment of the structure of the present invention.

[0026] Figure 2 This is an equivalent circuit diagram of the device structure of the present invention.

[0027] Figure 3 This is an IV curve diagram of the bidirectional TVS device of the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] like Figure 1-3 As shown, this embodiment discloses a shallow retrace bidirectional TVS structure, including a P-type silicon substrate layer, an Nwell region, an N+ region, a P+ region, a dielectric layer, and a metal electrode layer.

[0030] (1) The substrate material used is P-type silicon material with a resistivity between 500-2000 ohm·cm and boron as the doping element;

[0031] (2) In the Nwell1 and Nwell2 regions, the implanted element is phosphorus or arsenic, the implantation dose is 1.0E13-5.0E14, and the diffusion temperature is 900℃-1100℃;

[0032] (3) In regions N1 and N2, the injected element is phosphorus or arsenic, the injection dose is 1.0E15-1.0E16, and the diffusion temperature is 900℃-1100℃;

[0033] (8) In regions P1 and P2, the implanted element is boron, the implantation dose is 1.0E15-1.0E16, and the diffusion temperature is 900℃-1100℃;

[0034] (9) The porous dielectric layer is a silicon dioxide or a combination of silicon dioxide and silicon nitride;

[0035] (10) The metal is a conductive material. AlSiCu, Al, or Ag are used as electrode metals. The metal used to form the ohmic contact layer is Ti or Ti / TiN, and the metal thickness is between 3um and 6um.

[0036] like Figure 3 The IV curves shown indicate that using an NPN structure with shallow retracement for surge current discharge can effectively reduce clamping voltage and prevent latch-up effects.

[0037] The following definitions apply: VR: Working peak reverse voltage; IR: Reverse leakage current; VBR: Reverse breakdown voltage; IBR: Reverse breakdown current; VC: Clamping voltage; VTRIG: Reverse trigger voltage; ITRIG: Reverse trigger current; Ihold: Reverse holding current; IPP: Peak pulse current.

[0038] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A shallow retrace bidirectional TVS structure, characterized in that, The bidirectional TVS structure includes: The substrate is a lightly doped Si material of type P, i.e., a P-type substrate. The Nwell1 region is formed on a P-type substrate and has an N-type conductivity. The Nwell2 region is formed on a P-type substrate and has an N-type conductivity. The N1 region is formed in the Nwell1 region and has an N-type conductivity. The P1 region is formed in the Nwell1 region and has a P-type conductivity. The N2 region is formed in the Nwell2 region and has an N-type conductivity. The P2 region is formed in the Nwell2 region and has a P-type conductivity. A dielectric layer is formed on the upper surface of a P-type substrate; The metal electrode layer connects P1 and P2 through metal wiring. The N1 metal lead-out electrode is I / O1, and the N2 metal lead-out electrode is I / O2.

2. The shallow retrace bidirectional TVS structure as described in claim 1, characterized in that, The substrate material is P-type silicon, with a resistivity between 500-2000 ohm·cm, and the doping element is boron.

3. The shallow retrace bidirectional TVS structure as described in claim 1, characterized in that, Nwell1 and Nwell2 regions are formed on the front side of the P-type substrate by implanting arsenic or phosphorus at a dose of 1.0E13-5.0E14 and a diffusion temperature of 900℃-1100℃.

4. The shallow retrace bidirectional TVS structure as described in claim 1, characterized in that, N1 and N2 regions are formed on the front sides of Nwell1 and Nwell2 regions respectively by implanting elemental arsenic or phosphorus, with an implantation dose of 1.0E15-1.0E16 and a diffusion temperature of 900℃-1100℃.

5. The shallow retrace bidirectional TVS structure as described in claim 1, characterized in that, P1 and P2 regions were formed on the front sides of the Nwell1 and Nwell2 regions respectively by implanting elemental boron, with an implantation dose of 1.0E15-1.0E16 and a diffusion temperature of 900℃-1100℃.

6. The shallow retrace bidirectional TVS structure as described in claim 1, characterized in that, The dielectric layer is silicon dioxide or a combination of silicon dioxide and silicon nitride.

7. The shallow retrace bidirectional TVS structure as described in claim 1, characterized in that, The metal in the metal electrode layer is a conductive material, using AlSiCu, Al, or Ag as the electrode metal, and the metal forming the ohmic contact layer is Ti or Ti / TiN, with a metal thickness between 3um and 6um.

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