CN110718545A - Low residual voltage ESD surge protection device with low-capacitance structure - Google Patents

Abstract

The invention discloses a low residual voltage ESD surge protection device with a low-capacitance structure, which comprises a capacitance reducing tube D1, a TVS tube D4, a Schottky tube D2, an NPN tube T1 and a forward capacitance reducing tube D3 which are connected in an electrical connection manner; wherein the capacitance reducing tube D3 provides a forward current path; d1 and T1 form a PNPN structure which is a main discharge channel; the TVS tube D4 provides a turn-on voltage. The invention has reasonable design, realizes the protection device with the unidirectional large snapback SCR structure, realizes the SCR structure protection device with the extremely low capacitance through a double-groove process, can meet the current low residual voltage protection requirement, and has the characteristics of low capacitance, low clamping, large surge current capacity and the like.

Description

A low-capacitance low-residual-voltage ESD surge protection device

technical field

The invention belongs to a semiconductor component device, and more particularly, relates to a low-residual-voltage ESD surge protection device with a low-capacitance structure.

Background technique

Due to process limitations, vertical low residual voltage devices are limited by the Zener+R2R structure, and the residual voltage has been difficult to reduce. As the protection of the signal port is weakened by the freewheeling problem, the SCR structure has become the most effective way to reduce the residual voltage of the device. However, in order to realize the device of the unidirectional SCR structure, various processes are used to make the protection device of the SCR structure. There is an advantage that the process becomes very complex in the forward implementation of the device due to the use of a multi-layer structure. The planar structure is relatively simpler, but in order to obtain the breakdown voltage that needs to be operated, a relatively low doping concentration has to be used to reduce the breakdown voltage, which makes it difficult to achieve very low capacitance.

SUMMARY OF THE INVENTION

In view of the deficiencies in the prior art, the purpose of the present invention is to provide a low-capacitance structure and low residual voltage ESD surge protection device, the design is reasonable, and the unidirectional large snapback SCR structure protection device can be realized through double trenches. The technology realizes a very low capacitance SCR structure protection device, which can meet the current low residual voltage protection requirements, and the device has the characteristics of low capacitance, low clamping and large surge current capacity.

For achieving the above object, the present invention provides the following technical solutions:

A low-capacitance low-residual-voltage ESD surge protection device, characterized in that it includes a derating tube D1, a TVS tube D4, a Schottky tube D2, an NPN tube T1, and a forward de-rating tube D3 connected through an electrical connection relationship ; Among them, the derating tube D3 provides a forward current path; D1 and T1 form a PNPN structure, which is the main discharge channel; TVS tube D4 provides a turn-on voltage.

As an optimized technical solution, the TVS tube is composed of an N-type substrate, an N+ extension area and a P+ extension area in sequence from bottom to top, wherein the cathode of the TVS tube is the N+ extension area, and the N+ extension area is located in the central position; P+ The expansion area is used to make the anode of the TVS tube.

As an optimized technical solution, the main discharge channel is composed of two substrate N+Deep regions, N-Epi regions, P+ base regions and N+ emitter regions in sequence from bottom to top; two substrate N+Deep regions It is arranged on both sides of the N-Epi region; the position of the P+ base region is above the N+ emitter region, and there is an equal distance around the center of the anode of the TVS tube, so that the cathode short-circuit hole has the same potential when the gate is triggered. cathode shorting hole.

The present invention also provides a manufacturing process of the low residual voltage ESD surge protection device:

Proceed as follows:

On the highly doped P+ substrate material, the N+ buried layer region is formed by implantation annealing; the epitaxial layer N-Epi is grown, the N+ Deep region is formed by implantation annealing, and the N+ extension region and P+ extension region are formed respectively by implantation annealing. deep groove etching to form a trench, fill the trench with silicon dioxide, and then through a wet etching process to form a mesa trench, deposit a metal layer to form a metal interconnection, so that the metal and the substrate N+Deep region, P+ zone and N-Epi zone connection.

Due to the adoption of the above technical solution, compared with the prior art, the present invention has a reasonable design, realizes a protection device with a unidirectional large snapback SCR structure, and realizes a protection device with an extremely low capacitance SCR structure through a double trench process. Meet the current low residual voltage protection requirements, and the device has the characteristics of low capacitance, low clamping and large surge current capacity.

The present invention will be further described with reference to the accompanying drawings and embodiments.

Description of drawings

1 is a schematic circuit diagram of an embodiment of the present invention;

FIG. 2 is a schematic diagram of the overall structure of an embodiment of the present invention after the preparation is completed.

Detailed ways

Example

As shown in Figure 1, a low-capacitance low-residual-voltage ESD surge protection device includes a derating tube D1, a TVS tube D4, a Schottky tube D2, an NPN tube T1 and a forward derating tube connected through an electrical connection relationship Tube D3; among them, the derating tube D3 provides a forward current path; D1 and T1 form a PNPN structure, which is the main discharge channel; TVS tube D4 provides a turn-on voltage.

The TVS tube is composed of an N-type substrate, an N+ extension area and a P+ extension area from bottom to top, wherein the cathode of the TVS tube is an N+ extension area, and the N+ extension area is located at the central position; the P+ extension area is used to make the TVS tube. anode.

The main discharge channel is composed of two substrate N+Deep regions, N-Epi regions, P+ base regions and N+ emitter regions in sequence from bottom to top; the two substrate N+Deep regions are arranged on two sides of the N-Epi region. The position of the P+ base region is above the N+ emitter region, and a cathode short-circuit hole that can have the same potential on the cathode short-circuit hole when the gate is triggered is left equidistant around the center of the anode of the TVS tube.

The above-mentioned device is a double-trench process device, the trench provides device isolation, and the trench is used to connect the substrate with the N+IOS and the surface P+ region. The device is an epitaxial low-capacitance device, and N-Epi provides low-capacitance support for the device. The device is a one-way device, which can form a dual-channel and multi-channel protection device through the original package structure of the array.

As shown in Figure 2, the manufacturing process of the low residual voltage ESD surge protection device is as follows: an N+ buried layer region is formed on a highly impurity P+ substrate material by implantation annealing; an epitaxial layer N-Epi is grown and formed by implantation annealing N+Deep area, and then through implantation annealing method, respectively form N+ expansion area and P+ expansion area; deep trench etching forms trenches, the trenches are filled with silicon dioxide, and then wet etching process is used to form mesa trenches, depositing A metal layer is deposited to form a metal interconnection, so that the metal is connected to the N+Deep region, the P+ region and the N-Epi region of the substrate.

The present invention has a reasonable design, realizes a protection device with a unidirectional large snapback SCR structure, and realizes a protection device with an extremely low capacitance SCR structure through a double trench process, which can meet the current low residual voltage protection requirements, and the device has a low capacitance. , low clamping and large surge current capability.

The protection scope of the present invention is not limited to the above-mentioned embodiments, and all technical solutions that belong to the idea of the present invention belong to the protection scope of the present invention. It should be pointed out that for those skilled in the art, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims (4)

1. The utility model provides a low residual voltage ESD surge protector of low-capacitance structure which characterized in that: the device comprises a capacity reducing tube D1, a TVS tube D4, a Schottky tube D2, an NPN tube T1 and a forward capacity reducing tube D3 which are connected in an electrical connection relationship;

wherein the capacitance reducing tube D3 provides a forward current path; d1 and T1 form a PNPN structure which is a main discharge channel; the TVS tube D4 provides a turn-on voltage.

2. The low residual voltage ESD surge protection device with low capacitance structure as claimed in claim 1, wherein: the TVS tube consists of an N-type substrate, an N + expansion region and a P + expansion region from bottom to top in sequence, wherein the cathode of the TVS tube is the N + expansion region, and the N + expansion region is positioned in the center; the P + expansion region is used for manufacturing an anode of the TVS tube.

3. The low residual voltage ESD surge protection device with low capacitance structure as claimed in claim 2, wherein: the main discharge channel is composed of two substrate N + Deep regions, an N-Epi region, a P + base region and an N + emitter region from bottom to top in sequence; the two substrate N + Deep regions are arranged on two sides of the N-Epi region; the P + base region is positioned above the N + emitter region, and cathode short-circuit holes which can enable the gate electrode to have the same potential when the gate electrode is triggered are reserved at equal intervals around the center of the anode of the TVS tube.

4. A low residual voltage ESD surge protection device with low capacitance structure as claimed in claim 3, wherein:

the manufacturing process of the low residual voltage ESD surge protection device comprises the following steps: forming an N + buried layer region on the high-doped P + substrate material in an injection annealing mode; growing an epitaxial layer N-Epi, forming an N + Deep region through implantation annealing, and respectively forming an N + expansion region and a P + expansion region through an implantation annealing mode; and etching the Deep groove to form a groove, filling silicon dioxide in the groove, forming a mesa groove by a wet etching process, depositing a metal layer to form metal interconnection, and connecting the metal with the N + Deep region, the P + region and the N-Epi region of the substrate.

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