阅读说明：本技术 一种具有过压保护功能的晶闸管及制造方法 (Thyristor with overvoltage protection function and manufacturing method thereof ) 是由 王亚飞 王政英 朱春林 苏元洪 王彦刚 戴小平 于 2019-02-21 设计创作，主要内容包括：本发明公开了一种具有过压保护功能的晶闸管及制造方法,晶闸管包括：依次设置的由第一导电类型半导体材料制成的第一导电层、由第二导电类型半导体材料制成的衬底层和由第一导电类型半导体材料制成的第二导电层；在第一导电层的远离衬底层的一面上设置的阳极金属电极；在第二导电层内间隔设置的由第二导电类型半导体材料制成的发射极区；及在第二导电层上对应发射极区分别设置的浮空金属电极和阴极金属电极,衬底层向第二导电层的方向延伸将第二导电层分隔成两个第二导电区,两个第二导电区内均设置发射极区；两个第二导电区均包括基部和沿基部朝向另一第二导电区延伸的延伸部。本发明的结构简单,能够与IGBT模块并联后保护IGBT模块不被过电压损坏。(The invention discloses a thyristor with overvoltage protection function and a manufacturing method thereof, wherein the thyristor comprises: a first conductive layer made of a first conductive type semiconductor material, a substrate layer made of a second conductive type semiconductor material, and a second conductive layer made of the first conductive type semiconductor material, which are arranged in this order; the anode metal electrode is arranged on one surface, far away from the substrate layer, of the first conducting layer; emitter regions made of a semiconductor material of the second conductivity type provided at intervals in the second conductive layer; the substrate layer extends towards the direction of the second conducting layer to divide the second conducting layer into two second conducting areas, and the emitter areas are arranged in the two second conducting areas; both second conductive areas comprise a base portion and an extension portion extending along the base portion towards the other second conductive area. The invention has simple structure and can protect the IGBT module from being damaged by overvoltage after being connected with the IGBT module in parallel.)

1. A thyristor having an overvoltage protection function, comprising:

a first conductive layer made of a first conductive type semiconductor material, a substrate layer made of a second conductive type semiconductor material, and a second conductive layer made of the first conductive type semiconductor material, which are arranged in this order;

the anode metal electrode is arranged on one surface, far away from the substrate layer, of the first conducting layer;

emitter regions made of a second conductive type semiconductor material provided at intervals in the second conductive layer; and

floating metal electrodes and cathode metal electrodes respectively disposed on the second conductive layer corresponding to the emitter regions,

wherein the substrate layer extends in a direction of the second conductive layer to separate the second conductive layer into two second conductive regions, both of which have the emitter region disposed therein;

both of the second conductive areas include a base portion and an extension portion extending along the base portion toward the other of the second conductive areas.

2. The thyristor with overvoltage protection function according to claim 1, wherein the two second conductive regions have the same shape.

3. The thyristor with overvoltage protection function according to claim 1, wherein the extension has a thickness of 800 μm to 1000 μm, and a length of 70 μm to 120 μm.

4. The thyristor with overvoltage protection function according to claim 1 or 3, wherein the distance between the two extensions is 50 μm to 220 μm.

5. The thyristor with overvoltage protection according to claim 1 or 2, characterized in that the thyristor further comprises an oxide layer arranged on a side of the two extensions that is remote from the substrate layer.

6. The thyristor with overvoltage protection function according to claim 5, wherein the oxide layer is made of silicon dioxide.

7. The thyristor with overvoltage protection function according to claim 1, wherein a concentration of the semiconductor material of the first conductivity type constituting the extension portion is higher than a concentration of the semiconductor material of the first conductivity type constituting the base portion.

8. Thyristor with overvoltage protection function according to claim 1 or 7, characterized in that the concentration of the semiconductor material of the first conductivity type constituting the extension is 10¹⁸～10²⁰cm^-3。

9. A method of manufacturing a thyristor having overvoltage protection, comprising:

doping a first conductive type semiconductor material on two opposite sides of a substrate layer made of a second conductive type semiconductor material to form a first conductive layer and a second conductive layer;

etching a central region of the second conductive layer to expose the substrate layer to form two spaced apart second conductive regions, advancing the two second conductive regions toward the substrate layer;

doping a second conductivity type semiconductor material within both of said second conductive regions away from the surface of said substrate layer to form spaced emitter regions;

doping a first conductivity type semiconductor material in both of said second conductivity regions away from the surface of said substrate layer to form an extension at the base of said second conductivity region toward the other of said second conductivity regions, wherein doping of the first conductivity type semiconductor material is also performed around said emitter region on the surface in both of said second conductivity regions away from said substrate layer;

arranging an anode metal electrode on one surface of the first conducting layer, which is far away from the substrate layer;

and respectively arranging a floating metal electrode and a cathode metal electrode on one surfaces of the two second conductive regions far away from the substrate layer, corresponding to the emitter regions.

10. The method of manufacturing a thyristor having an overvoltage protection function according to claim 9, further comprising:

and arranging an oxide layer on one surface of the second conducting layer, which is far away from the substrate layer, corresponding to the central area.

Technical Field

The invention belongs to the technical field of electronic devices, and particularly relates to a thyristor with an overvoltage protection function and a manufacturing method thereof.

Background

An Insulated Gate Bipolar Transistor (IGBT) is a power semiconductor device in which an MOS Transistor (field effect Transistor) and a Bipolar Transistor are combined, has the advantages of low driving power, reduced on-state voltage, low switching loss, high current density, and the like, and is widely used in the fields of rail transit and industrial transmission. However, in practical application, the core converter IGBT module in the circuit is sensitive to overvoltage, and is easily damaged if protective measures are lacked or the circuit is not used properly. For example, in the turn-off process of an IGBT module, because the collector current rapidly decreases, a very high peak overvoltage is often generated between the collector and emitter of the IGBT under the action of stray inductance and load inductance of the circuit; or in the application of high-voltage circuits such as flexible direct-current transmission and the like, the IGBT is very easy to break down due to spike overvoltage generated by system errors or lightning stroke factors, so that devices are damaged, and the normal work of the system is influenced.

To avoid the IGBT from being damaged by the peak overvoltage, the current major practice includes:

1) stray inductance in a loop is reduced on the design level, and the method needs to optimize the internal structure of the IGBT module, reduce the parasitic inductance, optimize the structure of a main circuit and reduce the stray inductance. Although it can relieve the stress on the IGBT module caused by the overvoltage, its effect is limited.

2) When reducing return circuit stray inductance, for the IGBT module design external protection circuit on the circuit aspect, for example, external protection circuit includes TVS (transient voltage suppression diode), resistance, electric capacity and inductance etc. monitors IGBT's collector voltage, and when IGBT's collector voltage exceeded the predetermined value, TVS transmitted overvoltage signal for drive control circuit, and lifting IGBT grid potential triggered IGBT is in order to restrain IGBT collector voltage's rise. The protection circuit adopted by the method needs a plurality of electronic elements to realize, and the structure is complex; in high voltage circuit applications such as flexible direct current transmission, the protection method has a serious disadvantage that energy generated by overvoltage needs to be released through the IGBT module, and the IGBT module is likely to be overheated and damaged.

Therefore, how to realize an electronic device with a simple structure and an overvoltage protection function to protect the IGBT when the collector voltage of the IGBT reaches a predetermined value becomes a technical problem to be solved urgently.

Disclosure of Invention

One of the technical problems to be solved by the invention is how to realize an electronic device which has a simple structure and an overvoltage protection function so as to protect an IGBT when the voltage of a collector of the IGBT reaches a preset value.

In order to solve the above technical problem, an embodiment of the present application first provides a thyristor having an overvoltage protection function, including: a first conductive layer made of a first conductive type semiconductor material, a substrate layer made of a second conductive type semiconductor material, and a second conductive layer made of the first conductive type semiconductor material, which are arranged in this order; the anode metal electrode is arranged on one surface, far away from the substrate layer, of the first conducting layer; emitter regions made of a second conductive type semiconductor material provided at intervals in the second conductive layer; and floating metal electrodes and cathode metal electrodes respectively arranged on the second conductive layer corresponding to the emitter regions, wherein the substrate layer extends towards the second conductive layer to separate the second conductive layer into two second conductive regions, and the emitter regions are arranged in the two second conductive regions; both of the second conductive areas include a base portion and an extension portion extending along the base portion toward the other of the second conductive areas.

Preferably, the two second conductive areas are identical in shape.

Preferably, the distance between the extension part and the anode metal electrode along the second conductive layer (i.e. the thickness of the extension part) is 800 μm to 1000 μm, and the distance between the extension part and the base part (i.e. the length of the extension part) is 70 μm to 120 μm.

Preferably, the distance between the two extending parts is 50-220 μm.

Preferably, the thyristor further comprises an oxide layer covering the two extensions on the side remote from the substrate layer.

Preferably, the material of the oxide layer is silicon dioxide.

Preferably, a concentration of the semiconductor material of the first conductivity type constituting the extension portion is higher than a concentration of the semiconductor material of the first conductivity type constituting the base portion.

Preferably, the concentration of the semiconductor material of the first conductivity type constituting the extension portion is 10¹⁸To 10²⁰cm^-3。

The embodiment of the invention also discloses a method for manufacturing the thyristor with the overvoltage protection function, which comprises the following steps:

doping a first conductive type semiconductor material on two opposite sides of a substrate layer made of a second conductive type semiconductor material to form a first conductive layer and a second conductive layer;

etching a central region of the second conductive layer to expose the substrate layer to form two spaced apart second conductive regions, advancing the two second conductive regions toward the substrate layer;

doping a second conductivity type semiconductor material within both of said second conductive regions away from the surface of said substrate layer to form spaced emitter regions;

doping a first conductivity type semiconductor material in both of said second conductivity regions away from the surface of said substrate layer to form an extension at the base of said second conductivity region toward the other of said second conductivity regions, wherein doping of the first conductivity type semiconductor material is also performed around said emitter region on the surface in both of said second conductivity regions away from said substrate layer;

arranging an anode metal electrode on one surface of the first conducting layer, which is far away from the substrate layer;

and respectively arranging a floating metal electrode and a cathode metal electrode on one surfaces of the two second conductive regions far away from the substrate layer, corresponding to the emitter regions.

Preferably, the method further comprises the following steps:

and arranging an oxide layer on one surface of the second conducting layer, which is far away from the substrate layer, corresponding to the central area.

Compared with the prior art, one or more embodiments in the above scheme can have the following advantages or beneficial effects:

when the thyristor with the overvoltage protection function is in a forward blocking state, forward leakage current can be generated inside the thyristor, and the forward leakage current is increased along with the increase of the forward blocking voltage of the thyristor. When the forward blocking voltage of the thyristor reaches a predetermined value, the forward leakage current increases to a trigger current to trigger the thyristor. Thus, the thyristor can be triggered on without an external gate drive circuit. In addition, the thyristor does not need to lead out a gate metal electrode from the second conducting layer, and is easy to prepare in practice.

The thyristor is used for protecting the IGBT module when the thyristor is used in parallel with the IGBT module, when the collector voltage of the IGBT module (namely the voltage of the anode metal electrode of the thyristor) reaches a preset value, the thyristor can be triggered to be turned on without an external trigger signal, so that the collector voltage of the IGBT module is rapidly reduced, and the IGBT module is protected from being damaged by system overvoltage. And the thyristor is used as a main circuit current channel after being switched on, so that the energy generated by the overvoltage of the system can be further released.

By adopting the thyristor to protect the IGBT module, additional electronic components and external trigger circuits are not needed, and the complexity of a protection system is reduced.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

The accompanying drawings are included to provide a further understanding of the technology or prior art of the present application and are incorporated in and constitute a part of this specification. The drawings expressing the embodiments of the present application are used for explaining the technical solutions of the present application, and should not be construed as limiting the technical solutions of the present application.

Fig. 1 is a schematic structural diagram of a system in which a thyristor with an overvoltage protection function is connected in parallel with an IGBT module according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a thyristor with an overvoltage protection function according to an embodiment of the invention;

fig. 3 is a graph of the relationship between the distance between two extensions of a thyristor having an overvoltage protection function and the forward breakover voltage according to an embodiment of the present invention;

fig. 4 is a flow chart of a method of manufacturing a thyristor having an overvoltage protection function according to an embodiment of the invention;

fig. 5 is a schematic structural diagram after step S1 of fig. 4;

FIG. 6 is a schematic structural diagram after step S2 of FIG. 4

Fig. 7 is a schematic structural view after step S3 of fig. 4;

fig. 8 is a schematic structural view after step S4 of fig. 4;

fig. 9 is a schematic structural view after step S7 of fig. 4;

fig. 10 is a schematic structural diagram after step S6 of fig. 4.

Detailed Description

The following detailed description of the embodiments of the present invention will be provided with reference to the accompanying drawings and examples, so that how to apply the technical means to solve the technical problems and achieve the corresponding technical effects can be fully understood and implemented. The embodiments and the features of the embodiments can be combined without conflict, and the technical solutions formed are all within the scope of the present invention.

One of the technical problems to be solved by the embodiments of the present invention is: how to realize simple structure to have the electronic device of overvoltage protection function so that when IGBT collector voltage reaches the predetermined value, protect IGBT. In order to solve the above problem, an embodiment of the present invention provides a thyristor having an overvoltage protection function, including: a first conductive layer made of a first conductive type semiconductor material, a substrate layer made of a second conductive type semiconductor material, and a second conductive layer made of the first conductive type semiconductor material, which are arranged in this order; the anode metal electrode is arranged on one surface, far away from the substrate layer, of the first conducting layer; emitter regions made of a second conductive type semiconductor material provided at intervals in the second conductive layer; and floating metal electrodes and cathode metal electrodes respectively arranged on the second conductive layer corresponding to the emitter regions. Wherein the substrate layer extends in a direction of the second conductive layer to separate the second conductive layer into two second conductive regions, both of which have the emitter region disposed therein; both of the second conductive areas include a base portion and an extension portion extending along the base portion toward the other of the second conductive areas.

The thyristor with the overvoltage protection function can realize an NPNP four-layer structure on a substrate layer with silicon as a substrate, has a bidirectional blocking characteristic when not triggered, and has a unidirectional conducting characteristic after being triggered. When in a forward blocking state, a forward leakage current is generated inside the thyristor, and the forward leakage current increases with the increase of the forward blocking voltage of the thyristor. When the forward blocking voltage of the thyristor reaches a predetermined value, the forward leakage current increases to a trigger current to trigger the thyristor. The thyristor can be triggered on without the need for an external gate drive circuit. In addition, the thyristor does not need to lead out a gate metal electrode from the second conducting layer, and is easy to prepare in practice.

As shown in fig. 1, a thyristor with an overvoltage protection function is used in parallel with an IGBT module, and when a collector voltage of the IGBT module (i.e., a voltage of an anode metal electrode of the thyristor) reaches a predetermined value, the thyristor is triggered to turn on, so that the collector voltage of the IGBT module rapidly drops, thereby protecting the IGBT module from system overvoltage. And the thyristor is used as a main circuit current channel after being switched on, so that the energy generated by the overvoltage of the system can be further released.

The invention is further illustrated by the following specific examples.

Fig. 2 shows a thyristor with an overvoltage protection function according to an embodiment of the present invention. The thyristor of the present embodiment mainly includes a first conductive layer, a substrate layer, a second conductive layer, an anode metal electrode, an emitter region, a floating metal electrode, and a cathode metal electrode.

Specifically, the first conductive layer and the second conductive layer are both made of a first conductivity type semiconductor material, and the substrate layer is made of a second conductivity type semiconductor material. The first conducting layer, the substrate layer and the second conducting layer are arranged in sequence. An anode metal electrode 1 is provided on the side of the first conductive layer 2 remote from the substrate layer 3 (the lower surface as viewed in fig. 2). Emitter regions 5 made of a second conductive type semiconductor material are spaced within the second conductive layer. On the second conductive layer, floating metal electrodes 6 and cathode metal electrodes 7 are respectively arranged corresponding to the emitter regions 5, and referring to fig. 2, the substrate layer 3 extends towards the second conductive layer to divide the second conductive layer into two second conductive regions 4, and the emitter regions 5 are arranged in the two second conductive regions 4; both second conductive areas 4 comprise a base 8 and an extension 9 extending along the base 8 towards the other second conductive area 4. In this embodiment, the first conductive type semiconductor material is an N-shaped semiconductor material. The second conductive type semiconductor material is a P-shaped semiconductor material. Of course, the first conductive type semiconductor material may be selected as a P-type semiconductor material. The second conductivity type semiconductor material may also be selected to be an N-shaped semiconductor material.

A forward leakage current generated inside the thyristor serves as its trigger current, wherein one path of the trigger current is a path along the substrate layer 3, the extension portion 9, the base portion 8, the emitter region 5, or another path of the trigger current is a path along the substrate layer 3, the base portion 8, the emitter region 5. The thyristor is triggered by the trigger currents of the two paths together, and a gate metal layer does not need to be led out of the second conducting layer, so that the complexity of the thyristor manufacturing process is reduced; and when the thyristor is used for protecting the IGBT module, an additional gate drive circuit and a protection element are not needed, so that the complexity of a protection system is reduced.

Both of the second conductive areas 4 include a base portion 8 and an extension portion 9, the extension portion 9 of the first second conductive area 4 is formed to extend along the base portion 8 of the first second conductive area 4 toward the second conductive area 4, and the extension portion 9 of the second conductive area 4 is formed to extend along the base portion 8 of the second conductive area 4 toward the first second conductive area 4. The base portion 8 and the extension portion 9 of the second conductive region 4 constitute a step shape in a direction perpendicular to a direction from the anode metal electrode 1 to the second conductive layer.

In one embodiment, the two second conductive areas 4 are identical in shape. The base portions 8 of the two second conductive areas 4 are of the same shape and the extension portions 9 of the two second conductive areas 4 are of the same shape.

As shown in fig. 2, the extension portion 9 can be divided into a first extension region 91 and a second extension region 92, the first extension region 91 covers the side of the base portion 8 away from the substrate layer 3, and the second extension region 92 directly covers the side of the substrate layer 3 away from the first conductive layer 2. The thickness of the first extension region 91 is smaller than that of the second extension region 92 so that the extension portion 91 has an overall shape like a bird's beak in cross section. In one embodiment, the distance between the extension portion 9 and the anode metal electrode 1 along the second conductive layer, i.e. the thickness of the extension portion 9, is 800 μm to 1000 μm. The distance that the extension 9 extends from the base 8, i.e., the length of the extension 9, is 70 to 120 μm. The size of the extension portion 9 can be set according to the forward breakover voltage of the thyristor required by practical application.

In one embodiment, the distance between the two extensions 9 is 50 μm to 220 μm. Fig. 3 shows a diagram of the distance L between two extensions 9 as a function of the forward breakover voltage of the thyristor. According to the actual application requirement, the thyristor can have a desired forward breakover voltage by adjusting the distance between the two extension parts 9.

In an embodiment the thyristor further comprises an oxide layer 10 arranged on a side of the covering two extensions 9 facing away from the substrate layer 3. Wherein an oxide layer 10 is provided on the spacer region between the two extensions 9.

In one embodiment, the material of the oxide layer 10 is silicon dioxide. Wherein, the thickness of the oxide layer 10 may be 1 μm to 5 μm.

In one embodiment, the concentration of the semiconductor material of the first conductivity type constituting the extension portion 9 is higher than the concentration of the semiconductor material of the first conductivity type constituting the base portion 8.

In one embodiment, the concentration of the semiconductor material of the first conductivity type constituting the extension 9 is 10¹⁸To 10²⁰cm^-3。

The embodiment of the invention also discloses a method for manufacturing the thyristor with the overvoltage protection function, which comprises the steps S1 to S7 as shown in FIG. 4.

In step S1, doping of the first conductivity type semiconductor material is performed on opposite sides (e.g., upper and lower surfaces) of the substrate layer 3 made of the second conductivity type semiconductor material to form the first conductive layer 2 and the second conductive layer, as shown in fig. 5.

The thyristor with the overvoltage protection function can be manufactured by selecting a proper N-type silicon single crystal substrate as the substrate layer 3 according to the forward voltage-resistant grade of the IGBT module. The doping of the semiconductor material of the first conductivity type is carried out on both sides of the substrate layer 3 made of the semiconductor material of the second conductivity type, and the P-type doping can be carried out in a predeposition or ion implantation mode.

In step S2, a central area of the second conductive layer is etched to expose the second conductive type semiconductor material of the substrate layer 3 in the central area, thereby forming two spaced apart second conductive areas 4, and the two second conductive areas 4 are pushed towards the substrate layer 3, as shown in fig. 6. It is noted that only one conductive area 4 is shown in fig. 6.

Etching the central area of the second conductive layer to expose the second conductivity type semiconductor material of the substrate layer 3 in the central area to form two spaced apart second conductive regions 4 may be selectively etching the central area silicon to a thickness of 5-10 μm. Advancing the two second conductive areas 4 towards the substrate layer 3 may be performing an advancing of the P-base area.

In step S3, doping of a second conductivity type semiconductor material is performed within the two second conductive regions 4 away from the surface of the substrate layer 3 to form spaced emitter regions 5, as shown in fig. 7.

The doping of the second conductivity type semiconductor material in the two second conductive regions 4 at the surface remote from the substrate layer 3 may be selectively N-doped by means of predeposition or ion implantation and carried out to form N + emitter regions 5.

In step S4, the doping of the first conductivity type semiconductor material is performed in the surfaces of the two second conductive regions 4 remote from the substrate layer 3 to form extensions 9 at the bases 8 of the second conductive regions 4 towards the other second conductive region 4, wherein the doping of the first conductivity type semiconductor material is also performed around the emitter regions 5 on the surfaces of the two second conductive regions 4 remote from the substrate layer, as shown in fig. 8.

Step S4 may be, for example, selectively P-doping the surfaces of the two second conductive regions 4 away from the substrate layer 3 by means of pre-deposition or ion implantation, and performing the advancement to form P + regions.

In step S5, an anode metal electrode 1 is disposed on a side of the first conductive layer 2 away from the substrate layer 3, as shown in fig. 10;

in step S6, floating metal electrodes 6 and cathode metal electrodes 7 are provided on the sides of the two second conductive regions 4 remote from the substrate layer 3, corresponding to the emitter regions 5, as shown in fig. 10.

In addition, the thyristor can be formed by terminal modeling and passivation, and the process is the same as that of a common thyristor, and is not described again.

In one embodiment, the method for manufacturing a thyristor with an overvoltage protection function further includes:

in step S7, an oxide layer 10 is provided on the side of the second conductive layer remote from the substrate layer 3, corresponding to the central area, as shown in fig. 9. The oxide layer 10 provided in the central region may be, for example, a silicon dioxide oxide layer deposited to a thickness of about 1 μm to 5 μm.

Wherein step S7 may be implemented before step S6.

The thyristor with the overvoltage protection function manufactured by the manufacturing method is used in parallel with the IGBT module, and when the voltage of the collector of the IGBT module (namely the voltage of the anode metal electrode of the thyristor) reaches a preset value, the thyristor is triggered to be turned on, so that the voltage of the collector of the IGBT module is rapidly reduced, and the IGBT module is protected from being damaged by system overvoltage. And the thyristor is used as a main circuit current channel after being switched on, so that the energy generated by the overvoltage of the system can be further released.

The above description is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.