CN218730958U - Insulated gate bipolar transistor with improved short circuit endurance - Google Patents

Abstract

The utility model discloses an insulated gate bipolar transistor with improve short circuit endurance, insulated gate bipolar transistor IGBT includes: a body region, a drift region and an N-type FS field termination region; an emitter and a grid are arranged above the main body region; a P-type collector region is arranged below the N-type FS region, and a collector electrode is arranged below the P-type collector region; the gate region comprises a trench gate and a planar gate; the planar gate is arranged on the surface of the gate region, a groove is formed in the preset position of the gate region, the groove gate is arranged in the groove, one end, far away from the bottom end of the groove, of the groove gate is connected with an insulating layer, and the insulating layer covers the outer surface of the planar gate. The utility model discloses can improve and switch on the voltage drop, lead to big short-circuit bearing capacity and low Vce (sat).

Description

Insulated gate bipolar transistor with improved short circuit endurance

Technical Field

The utility model relates to the field of semiconductors, and in particular to insulated gate bipolar transistor with improve short circuit endurance.

Background

Insulated Gate Bipolar Transistor (IGBT) is the most widely used power device in power electronics applications such as household appliances, industry, renewable energy, UPS, rail, motor drive, EV and HEV applications, and it has very high current handling capability in its structure, about several hundred amperes, blocking voltage 6500V due to the presence of Bipolar junction transistors. These IGBTs can control loads of hundreds of kilowatts and are suitable for many applications. IGBTs are particularly well suited for duty cycle, low frequency, high voltage and load variation, enabling their use in locomotives, trains, electric vehicles and hybrid electric vehicles. Applications of IGBTs in Electric Vehicles (EV) and Hybrid Electric Vehicles (HEV) include their use in power trains and chargers for delivering and controlling electric power to electric machines. The IGBT market of EV/HEV is expected to grow twice in the prediction period, accounting for more than 50% of the whole market.

However, IGBTs have an inherent disadvantage, such as the rapid increase in Vce (sat) with increasing blocking voltage, and the IEGT concept has been developed to reduce the on-state voltage drop. The trench gate power device reduces channel resistance and eliminates JFET effects and can reduce on-state voltage drop. Furthermore, the IEGT (injection enhanced IGBT) concept increases the storage carriers on the upper side of the n-drift region by using floating p-regions between trench-gate cells, thus significantly reducing Vce (sat) for relatively high voltage IGBTs.

These power devices applied to hybrid vehicles and electric vehicles are frequently forced to face a severe environment, and from the viewpoint of device failure and protection, it is very useful to analyze failure mechanisms and innovate major measures for failure and destruction according to the failure mechanisms. One of the most important damage phenomena is damage under short circuit conditions in inverter applications. Generally, it can be said that the most damaging condition is under high power switching. The IGBT structure must be able to operate in the entire area covering these tracks without destructive failure. During the process of simultaneously withstanding large currents and voltages in an IGBT structure, a phenomenon known as avalanche-induced secondary breakdown occurs, resulting in a destructive failure. This phenomenon can be triggered both during the opening transient and during the closing transient. During the turn-on transient, the Forward Bias Safe Operating Area (FBSOA) is said to be limited. During the turn-off transient, the Reverse Bias Safe Operating Area (RBSOA) is said to be limited. Very severe stresses including FBSOA and RBSOA occur under short circuit conditions, and the failure mechanism of short circuit operation can be considered to be divided into four modes.

Mode a is a breakdown that occurs within a few microseconds after turn-on, due to the parasitic bipolar transistor turning on when the collector current is large. Mode B is a thermal disruption caused by excessive power consumption. Mode C is the disruption observed during shutdown, with dic/dt increasing and a higher peak voltage occurring shortly before Ic reaches zero current level. If the Rg turn-off resistance is reduced to a very small value and the parasitic inductance is large, dynamic avalanche can occur due to a destructive event caused by current filamentation, and SSCM (switched self-clamping mode) can occur, clamping the peak voltage to the breakdown voltage. Mode D is a failure observed about a few hundred microseconds after shutdown and can be described as thermal runaway caused by large leakage currents.

Short circuit withstand capability has been one of the most important issues for IGBTs and IGETs in EV, HEV and high power motor control applications. Many requirements in applications running under hard switching conditions are driving the IGBT development trend towards wide SOA limits. Improved SOA performance will positively impact manufacturability, reliability, power handling capability, better controllability, better system and gate device design, with the aim of reducing overall losses and employing more optimal protection schemes. To ensure that high voltage devices do not exceed their SOA limits, many limitations are introduced to the operation of such devices. Accordingly, system designers have decided to set many circuits and gate drive parameters accordingly. Such modifications include increasing the gate resistance and including protective active clamps or buffers.

This increased complexity often negatively impacts the performance, cost, and size of high power electronic systems. Therefore, how to greatly improve the SOA of the IGBT and the IEGT and improve the short-circuit tolerance capability without sacrificing the trade-off relationship between the performance and the technology becomes a technical problem to be solved urgently.

SUMMERY OF THE UTILITY MODEL

In view of the above, the present invention is directed to an insulated gate bipolar transistor IGBT with improved short circuit endurance.

Particularly, the utility model provides an insulated gate bipolar transistor with improve short circuit endurance, insulated gate bipolar transistor IGBT includes: a body region, a drift region and an N-type Field Stop FS (Field Stop) region; an emitter and a grid are arranged above the main body region; a P-type collector region is arranged below the N-type FS region, and a collector electrode is arranged below the P-type collector region; the gate region comprises a trench gate and a planar gate; the planar gate is arranged on the surface of the gate region, a groove is formed in the preset position of the gate region, the groove gate is arranged in the groove, one end, far away from the bottom end of the groove, of the groove gate is connected with an insulating layer, and the insulating layer covers the outer surface of the planar gate.

Further, the emitter region is an N-type emitter region, the gate region is a P-type base region, the P-type base region is arranged around the trench gate, and the N-type emitter region is arranged at one end, close to the insulating layer, of the trench gate.

Further, a gate oxide layer is arranged on the outer surface of the trench gate.

Further, the insulated gate bipolar transistor is an injection enhancement type IGBT.

The utility model also provides a power electronic equipment, including above-mentioned insulated gate bipolar transistor.

Further, the power electronics device includes a current transformer.

The utility model also provides a power car, including foretell insulated gate bipolar transistor.

Further, the power vehicle includes a locomotive train, an electric vehicle or a hybrid electric vehicle.

The utility model discloses a IGBT with improve short circuit endurance can through the integrated configuration who has slot grid and planar grid, and peak saturation current under this structure can the restriction short circuit, and the reinforcing effect is injected into in the performance, improves and switches on the voltage drop, improves big short circuit bearing capacity.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention. In the drawings, like reference numerals are used to indicate like elements. The drawings in the following description are directed to some, but not all embodiments of the invention. For a person skilled in the art, other figures can be derived from these figures without inventive effort.

Fig. 1 is a schematic diagram of electric field and current distribution non-uniform in an IGBT chip in different local areas provided by an embodiment of the present invention;

fig. 2 is a schematic structural diagram of an insulated gate bipolar transistor with improved short circuit tolerance according to an embodiment of the present invention;

FIG. 3 isbase:Sub>A cross-sectional view taken along A-A' of FIG. 2;

FIG. 4 is a cross-sectional view taken along B-B' of FIG. 2;

fig. 5 is a cross-sectional view taken along line C-C' of fig. 2.

Detailed Description

The exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, which, however, may be embodied in many different forms and are not limited to the embodiments described herein, which are provided for the purpose of thoroughly and completely disclosing the present invention and fully conveying the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments presented in the accompanying drawings is not intended to be limiting of the invention. In the drawings, the same units/elements are denoted by the same reference numerals.

Unless otherwise defined, terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Further, it will be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense.

The inventor of the application finds out through experimental tests and theoretical analysis that the uneven electric field and the current cause several fault points in the chip, wherein the higher electric field is concentrated at the bottom of the trench gate and four corners of the chip. A higher current density is concentrated around the gate pad and gate runner, and a higher lattice temperature is below the emitter pad region. Specifically, as shown in fig. 1, the No.1 circle represents the point between the edge termination and the active cell area, no.2 represents the point around the emitter pad area, no.3 represents the point along the gate runner, and No.4 represents the point pad area around the gate.

The embodiments of the present invention provide a new concept device for breaking through the trade-off relationship between the turn-on voltage drop and the SCSOA, as shown in fig. 2 to 5. An insulated gate bipolar transistor (IGBT or IEGT) has a combined structure of a Trench gate (Trench gate) and a Planar gate (Planar gate), and this structure can limit the peak saturation current under short circuit, exert an injection enhancement effect, improve the on-state voltage drop, and result in a large short circuit withstand capability and low Vce (sat).

Referring to fig. 2 to 5, as an embodiment of the present invention, an IGBT with improved short circuit tolerance includes: a body region, a drift region and an N-type FS region; an emitter and a grid are arranged above the main body region; a P-type collector region is arranged below the N-type FS region, and a collector electrode is arranged below the P-type collector region; the gate region comprises a trench gate and a planar gate; the planar gate is arranged on the surface of the gate region, a groove is formed in the preset position of the gate region, the groove gate is arranged in the groove, one end, far away from the bottom end of the groove, of the groove gate is connected with an insulating layer, and the insulating layer covers the outer surface of the planar gate.

Preferably, the emitter region is an N-type emitter region, the gate region is a P-type base region, the P-type base region is arranged around the trench gate, and the N-type emitter region is arranged at one end of the trench gate adjacent to the insulating layer.

Further preferably, a gate oxide layer is arranged on the outer surface of the trench gate.

In the IGBT with the short-circuit endurance capability, the peak saturation current under short circuit can be limited by the structure through the combined structure of the groove grid and the plane grid, the injection enhancement effect is exerted, the conduction voltage drop is improved, and the bearing capability of a large short-circuit is improved.

The application also provides power electronic equipment comprising the insulated gate bipolar transistor. In particular, the power electronics may comprise a current transformer.

The application also provides a power vehicle which comprises the insulated gate bipolar transistor. Specifically, the vehicle includes a locomotive train, an electric vehicle, or a hybrid electric vehicle.

The above power electronic device and motor vehicle comprising the above-described igbt technical effect is capable of injecting hole carriers from the extra p + region into the space charge region during the short-circuit turn-off transient, thereby compensating the effective net charge density in the space charge to eliminate the peak electric field. Finally, dynamic avalanches leading to current filaments can be avoided. The injected carriers can be quickly removed by the extra n + region, thereby shortening the turn-off time.

The invention has been described with reference to a few embodiments. However, other embodiments of the invention than the above disclosed are equally possible within the scope of the invention, as would be apparent to a person skilled in the art, as defined by the appended patent claims.

Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the [ device, component, etc ]" are to be interpreted openly as referring to at least one instance of said device, component, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.

Claims (8)

1. An insulated gate bipolar transistor having improved short circuit endurance, comprising: a body region, a drift region and an N-type field stop FS region;

an emitter and a grid are arranged above the main body region; a P-type collector region is arranged below the N-type FS region, and a collector electrode is arranged below the P-type collector region;

the gate region comprises a trench gate and a planar gate; the planar gate is arranged on the surface of the gate region, a groove is formed in the preset position of the gate region, the groove gate is arranged in the groove, one end, far away from the bottom end of the groove, of the groove gate is connected with an insulating layer, and the insulating layer covers the outer surface of the planar gate.

2. The igbt of claim 1, wherein the emitter region is an N-type emitter region, and the gate region is a P-type base region, the trench gate is surrounded by the P-type base region, and the N-type emitter region is disposed at an end of the trench gate adjacent to the insulating layer.

3. The insulated gate bipolar transistor with improved short circuit endurance of claim 2, wherein said trench gate outer surface is provided with a gate oxide layer.

4. The insulated gate bipolar transistor according to any of claims 1-3, wherein said insulated gate bipolar transistor is an injection enhancement type Insulated Gate Bipolar Transistor (IGBT).

5. A power electronic device comprising an insulated gate bipolar transistor according to any of claims 1 to 4.

6. The power electronic device of claim 5, wherein the power electronic device comprises a current transformer.

7. A vehicle characterized by comprising the insulated gate bipolar transistor according to any one of claims 1 to 4.

8. The powered vehicle of claim 7, wherein the powered vehicle comprises a locomotive train, an electric vehicle, or a hybrid electric vehicle.

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