阅读说明：本技术 一种自隔离非对称垂直型瞬态电压抑制保护器件 (Self-isolation asymmetric vertical transient voltage suppression protection device ) 是由 朱伟东 赵泊然 于 2021-11-10 设计创作，主要内容包括：本发明公开了一种自隔离非对称垂直型瞬态电压抑制保护器件,包括P型衬底、N型基区、P型基区、第一N+注入区、第二N+注入区、第一P+注入区、第二P+注入区、第一表面结构和第二表面结构,第一表面结构包括第一场氧化层和第二电极金属层,第二表面结构包括第二场氧化层和第二电极金属层。本发明将NPN与PNP进行垂直整合,内部实现自隔离的同时,通过调整NPN与PNP基区掺杂浓度来调整其工作电压,很好地规避了二极管串带来的问题,既实现两个方向不同的维持电压Vh与回扫特性,又实现器件内部自隔离。(The invention discloses a self-isolation asymmetric vertical transient voltage suppression protection device which comprises a P-type substrate, an N-type base region, a P-type base region, a first N + injection region, a second N + injection region, a first P + injection region, a second P + injection region, a first surface structure and a second surface structure, wherein the first surface structure comprises a first field oxide layer and a second electrode metal layer, and the second surface structure comprises a second field oxide layer and a second electrode metal layer. The NPN and the PNP are vertically integrated, self-isolation is achieved inside the device, meanwhile, the working voltage of the device is adjusted by adjusting the doping concentration of the base regions of the NPN and the PNP, the problems caused by diode strings are well avoided, and the device achieves the characteristics of different holding voltages Vh and flyback in two directions and self-isolation inside the device.)

1. A self-isolating asymmetric vertical transient voltage suppression protection device, comprising:

a P-type substrate;

the N-type base region is arranged at the upper end of the P-type substrate, the outer side of the N-type base region is wrapped by the P-type substrate, the upper end of the N-type base region is exposed out of the P-type substrate and is flush with the P-type substrate, and the lower end of the N-type base region is immersed in the P-type substrate;

the P-type base region is arranged at the upper end of the P-type substrate, the outer side of the P-type base region is wrapped by the P-type substrate, the upper end of the P-type base region is exposed out of the P-type substrate and is flush with the P-type substrate, the lower end of the P-type base region is immersed into the P-type substrate, the P-type base region and the N-type base region are arranged in parallel, and a gap is formed between the P-type base region and the N-type base region;

the first N + injection region is arranged on the P-type base region, the outer side of the first N + injection region is wrapped by the P-type base region, and the upper end of the first N + injection region is exposed out of the P-type base region and is flush with the upper surface of the P-type base region;

the second N + injection region is arranged at the bottom end of the P-type substrate, the outer side of the second N + injection region is wrapped by the P-type substrate, the lower end of the second N + injection region is exposed out of the P-type substrate and is flush with the P-type substrate, the upper end of the second N + injection region is immersed in the P-type substrate, and the first N + injection region and the second N + injection region correspond to each other up and down;

the first P + injection region is arranged on the N-type base region, the outer side of the first P + injection region is wrapped by the N-type base region, and the upper end of the first P + injection region is exposed out of the N-type base region and is flush with the upper surface of the N-type base region;

the second P + injection region is arranged at the bottom end of the P-type substrate, the outer side of the second P + injection region is wrapped by the P-type substrate, the lower end of the second P + injection region is exposed out of the P-type substrate and is flush with the P-type substrate, the upper end of the second P + injection region is sunk into the P-type substrate, the first P + injection region and the second P + injection region vertically correspond to each other, the second P + injection region and the second N + injection region are arranged in parallel, and a gap is formed between the second P + injection region and the second N + injection region;

the first surface structure is arranged on the upper surface of the P-type substrate and used for chip packaging and welding;

and the second surface structure is arranged on the lower surface of the P-type substrate and is used for chip packaging and welding.

2. The self-isolating asymmetric vertical transient voltage suppression protection device of claim 1, wherein the first surface structure comprises a first field oxide layer and a first electrode metal layer, the first field oxide layer is disposed on an upper surface of the P-type substrate and covers a contact portion of the P-type base region and the N-type base region with the P-type substrate at an end surface, and the first electrode metal layer covers an upper surface of the first field oxide layer, the first N + injection region, the first P + injection region, the P-type base region and the N-type base region.

3. The self-isolating asymmetric vertical transient voltage suppression protection device of claim 1, wherein said second surface structure comprises a second field oxide layer and a second electrode metal layer, said second field oxide layer disposed on a lower surface of the P-type substrate and covering a second N + implant region and a second P + implant region where they meet the P-type substrate at the end face; and the second electrode metal layer covers the surfaces of the second field oxide layer, the second N + injection region and the second P + injection region.

4. The self-isolating asymmetric vertical transient voltage suppression protection device of claim 2, wherein the first electrode metal layer connects the first N + implant region and the first P + implant region as a first electrode.

5. The self-isolating asymmetric vertical transient voltage suppression protection device of claim 3, wherein the second electrode metal layer connects the second N + implant region and the second P + implant region as a second electrode.

6. The self-isolating asymmetric vertical transient voltage suppression protection device of claim 1, wherein the N-type base region is a tunable concentration PNP base region.

7. The self-isolating asymmetric vertical transient voltage suppression protection device of claim 1, wherein the P-type base region is a tunable concentration NPN base region.

Technical Field

The invention belongs to the field of electronic science and technology, and particularly relates to a self-isolation asymmetric vertical transient voltage suppression protection device.

Background

A Transient Voltage Suppressor (TVS) is a necessary surge protection device in system applications, and the applications of various TVSs are different. In a dual power line system, the two power sources tend to have different voltages, so an asymmetric TVS device is required to be designed in a floating manner between the two power sources, and the TVS is usually implemented by using a diode string. The diode string has high clamping voltage and weak protection capability, and a plurality of devices need to be connected in series in high-voltage application, so that the chip area is large, the cost is high, the cost efficiency ratio is low, and optimization is needed urgently.

For surge protection, a bidirectional NPN structure is a reliable device that can be used for surge design of a 5V power supply, but due to the symmetry of bidirectional NPN characteristics, it is difficult to apply to surge protection of an asymmetric power supply. And the PNP device is a weak flyback device and can be used for protecting various voltages.

Disclosure of Invention

In order to solve the technical problems in the prior art, the invention provides a self-isolation asymmetric vertical transient voltage suppression protection device, which vertically integrates NPN and PNP, realizes self-isolation internally, and adjusts the working voltage of the NPN and PNP by adjusting the doping concentration of the base regions of the NPN and PNP, thereby well avoiding the problems brought by diode strings, realizing the characteristics of different holding voltages Vh and flyback in two directions and realizing self-isolation internally of the device.

The invention mainly adopts the technical scheme that:

a self-isolating asymmetric vertical transient voltage suppression protection device, comprising:

a P-type substrate;

the N-type base region is arranged at the upper end of the P-type substrate, the outer side of the N-type base region is wrapped by the P-type substrate, the upper end of the N-type base region is exposed out of the P-type substrate and is flush with the P-type substrate, and the lower end of the N-type base region is immersed in the P-type substrate;

the P-type base region is arranged at the upper end of the P-type substrate, the outer side of the P-type base region is wrapped by the P-type substrate, the upper end of the P-type base region is exposed out of the P-type substrate and is flush with the P-type substrate, the lower end of the P-type base region is immersed into the P-type substrate, the P-type base region and the N-type base region are arranged in parallel, and a gap is formed between the P-type base region and the N-type base region;

the first N + injection region is arranged on the P-type base region, the outer side of the first N + injection region is wrapped by the P-type base region, and the upper end of the first N + injection region is exposed out of the P-type base region and is flush with the upper surface of the P-type base region;

the second N + injection region is arranged at the bottom end of the P-type substrate, the outer side of the second N + injection region is wrapped by the P-type substrate, the lower end of the second N + injection region is exposed out of the P-type substrate and is flush with the P-type substrate, the upper end of the second N + injection region is immersed in the P-type substrate, and the first N + injection region and the second N + injection region are arranged in a vertically corresponding mode;

the first P + injection region is arranged on the N-type base region, the outer side of the first P + injection region is wrapped by the N-type base region, and the upper end of the first P + injection region is exposed out of the N-type base region and is flush with the upper surface of the N-type base region;

the second P + injection region is arranged at the bottom end of the P-type substrate, the outer side of the second P + injection region is wrapped by the P-type substrate, the lower end of the second P + injection region is exposed out of the P-type substrate and is flush with the P-type substrate, the upper end of the second P + injection region is sunk into the P-type substrate, the first P + injection region and the second P + injection region vertically correspond to each other, the second P + injection region and the second N + injection region are arranged in parallel, and a gap is formed between the second P + injection region and the second N + injection region;

the first surface structure is arranged on the upper surface of the P-type substrate and used for chip packaging and welding;

and the second surface structure is arranged on the lower surface of the P-type substrate and is used for chip packaging and welding.

Preferably, first surface texture includes first field oxide and first electrode metal level, first field oxide sets up the upper surface at P type substrate, and covers P type base region and N type base region and the contact department of P type substrate at the terminal surface, first electrode metal level covers the upper surface at first field oxide, first N + injection region, first P + injection region, P type base region and N type base region.

Preferably, the second surface structure includes the second field oxide layer, the second field oxide layer is disposed on the lower surface of the P-type substrate and covers the second N + implantation region and the contact position of the second P + implantation region with the P-type substrate at the end surface; and the second electrode metal layer covers the surfaces of the second field oxide layer, the second N + injection region and the second P + injection region.

Preferably, the first electrode metal layer connects the first N + implantation region and the first P + implantation region as a first electrode.

Preferably, the second electrode metal layer connects the second N + injection region and the second P + injection region as a second electrode.

Preferably, the N-type base region is a PNP base region with adjustable concentration.

Preferably, the P-type base region is an NPN base region with adjustable concentration.

Has the advantages that: the invention provides a self-isolation asymmetric vertical transient voltage suppression protection device, which has the following advantages:

(1) the device has asymmetric pulse I-V characteristics, can realize a maintaining voltage of more than 5V and less than 7V in one direction to provide anti-latch-up surge protection of a 5V conventional power supply, and can realize a maintaining voltage of more than 7V and less than 10V in the other direction to provide anti-latch-up surge protection of higher voltage, and can be used for surge protection between dual power rails of a system;

(2) the internal of the device simultaneously realizes voltage-resistant self-isolation, and ensures that one direction does not cause crosstalk when the other direction works;

(3) the device has high integration level and has obvious advantages compared with the traditional diode string structure.

Drawings

FIG. 1 is a schematic vertical cross-sectional view of a self-isolating asymmetric structure of the present invention;

FIG. 2 is a schematic diagram of the I-V characteristics of a schematic diagram of a self-isolating asymmetric structure of the present invention;

in the figure: the field oxide layer structure comprises a first N + injection region 01, a first P + injection region 02, a second N + injection region 03, a second P + injection region 04, an N-type base region 11, a P-type base region 12, a P-type substrate 20, a first surface structure 30, a first field oxide layer 31, a first electrode metal layer 32, a second surface structure 40, a second field oxide layer 41 and a second electrode metal layer 42.

Detailed Description

In order to make those skilled in the art better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Example 1:

as shown in fig. 1, a self-isolating asymmetric vertical transient voltage suppression protection device includes: the semiconductor device comprises a P-type substrate 20, an N-type base region 11, a P-type base region 12, a first N + injection region 01, a second N + injection region 03, a first P + injection region 02, a second P + injection region 04, a first surface structure 30 and a second surface structure 40. The N-type base region 11 is arranged at the upper end of the P-type substrate 20, the outer side of the N-type base region 11 is wrapped by the P-type substrate 20, the upper end of the N-type base region 11 is exposed out of the P-type substrate 20 and is flush with the upper surface of the P-type substrate 20, and the lower end of the N-type base region 11 is sunk into the P-type substrate 20;

the P-type base region 12 is arranged at the upper end of a P-type substrate 20, the outer side of the P-type base region 12 is wrapped by the P-type substrate 20, the upper end of the P-type base region 12 is exposed out of the P-type substrate 20 and is flush with the upper surface of the P-type substrate 20, the lower end of the P-type base region 12 is sunk into the P-type substrate 20, the P-type base region 12 and the N-type base region 11 are arranged in parallel, and a gap is formed between the P-type base region 12 and the N-type base region 11;

the first N + injection region 01 is arranged on the P-type base region 12, the outer side of the first N + injection region 01 is wrapped by the P-type base region 12, and the upper end of the first N + injection region 01 is exposed out of the P-type base region 12 and is flush with the upper surface of the P-type base region 12;

the second N + injection region 03 is arranged at the bottom end of the P-type substrate 20, the outer side of the second N + injection region 03 is wrapped by the P-type substrate 20, the lower end of the second N + injection region 03 is exposed out of the P-type substrate 20 and is flush with the P-type substrate 20, the upper end of the second N + injection region 03 is immersed in the P-type substrate 20, and the first N + injection region 01 and the second N + injection region 03 are arranged in an up-and-down corresponding manner; the first N + injection region 01 and the second N + injection region 03 are both high-concentration donor impurity injection regions;

the first P + injection region 02 is arranged on the N-type base region 11, the outer side of the first P + injection region 02 is wrapped by the N-type base region 11, and the upper end of the first P + injection region 02 is exposed out of the N-type base region 11 and is flush with the upper surface of the N-type base region 11;

the second P + injection region 04 is arranged at the bottom end of the P-type substrate 20, the outer side of the second P + injection region 04 is wrapped by the P-type substrate 20, the lower end of the second P + injection region 04 is exposed out of the P-type substrate 20 and is flush with the P-type substrate 20, the upper end of the second P + injection region 04 is immersed into the P-type substrate 20, the first P + injection region 02 and the second P + injection region 04 are arranged up and down correspondingly, the second P + injection region 04 and the second N + injection region 03 are arranged in parallel, a gap is formed between the second P + injection region 03 and the second N + injection region 03, and the first P + injection region 02 and the second P + injection region 04 are high-concentration acceptor impurity injection regions;

the first surface structure 30 is arranged on the upper surface of a P-type substrate, is used for chip packaging and welding, and comprises a first field oxide layer 31 and a first electrode metal layer 32, wherein the first field oxide layer 31 is arranged on the upper surface of the P-type substrate 20 and covers the contact positions of the P-type base region 12, the N-type base region 11 and the P-type substrate 20 on the end surfaces, and the first electrode metal layer 32 covers the upper surfaces of the first field oxide layer 31, the first N + injection region 01, the first P + injection region 02, the P-type base region 12 and the N-type base region 11; as shown in fig. 1, a gap exists between the first field oxide layer 31 and two ends of the first N + implantation region 01 and the first P + implantation region 02, and the upper surface of the gap is covered with a first electrode metal layer 32; the first electrode metal layer 32 connects the first N + injection region 01 and the first P + injection region 02 as a first electrode;

the second surface structure 40 is disposed on the lower surface of the P-type substrate 20 for chip packaging and soldering. The field oxide layer 41 is arranged on the lower surface of the P-type substrate 20 and covers the contact positions of the second N + injection region 03 and the second P + injection region 04 with the P-type substrate 20 at the end face; the second electrode metal layer 42 covers the surfaces of the second field oxide layer 41, the second N + implantation region 03 and the second P + implantation region 04; the second electrode metal layer connects the second N + injection region and the second P + injection region as a second electrode.

In the present invention, the N-type base region is an adjustable concentration PNP base region, and the ion implantation dose of the N-type base region is 2E 12/cm-1E 14/cm; the P-type base region is an NPN base region with adjustable concentration, and the ion implantation dose of the P-type base region is 2E 12/cm-1E 14/cm.

The working principle of the invention is as follows:

when the first electrode discharges to the second electrode, as shown in fig. 2, Vt1 is a forward trigger voltage, the high-voltage PNP reverse bias collector junction formed by the N-type base region 11 and the P-type substrate 20 will reverse bias and prevent the conduction of the PNP channel, and the low-voltage collector junction between the first N + injection region 01 and the P-type base region 12 will break down to trigger the NPN flyback first, at this time, the voltage drop of the first electrode to the second electrode will be clamped by the NPN at about a forward sustain voltage Vh1 in fig. 2, and the forward sustain voltage Vh1 is generally greater than 5V and less than 7V, which can prevent the latch-up effect in this voltage range.

When the second electrode discharges the first electrode, as shown in fig. 2, Vt2 is the reverse trigger voltage, and the second P + implant region 04 and the P-type substrate 20 form the PNP transistor emitter. The second N + implantation region 03 and the P-type substrate 20 form a high voltage NPN reverse bias collector junction to prevent the NPN channel from conducting, and at the same time, the low voltage collector junction formed by the first P + implantation region 02 and the N-type base region 11 breaks down first, and at this time, the voltage of the second electrode to the first electrode is clamped at a reverse maintaining voltage Vh2 in fig. 2, and the reverse maintaining voltage Vh2 is above 7V, so as to prevent the latch-up effect in this voltage range.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.