Insulated gate bipolar transistor and control circuit

Abstract

The invention relates to an insulated gate bipolar transistor and a control circuit, comprising a gate structure, an N+ source region, a P-type body region, an N-base region and a P+ drain injection region, wherein the insulated gate bipolar transistor comprises an emitter covering the N+ source region and a collector covering the P+ drain injection region; the N-base region comprises an N-base region arranged close to the P-type body region, and the gate structure comprises a gate oxide covering the N+ source region, the P-type body region and the N-base region; the insulated gate bipolar transistor further comprises an isolation layer for isolating the P-type body region from the N-base region, the isolation layer is used to isolate the P-type body region from the N-base region, and then the N-base region is led out as a base control terminal; only when the insulated gate bipolar transistor is turned off, a reverse driving voltage is applied to the gate and a forward driving voltage is applied to the base, so that a reverse bias is formed between the N-base region and the P-type body region, and holes in the N-base region are accelerated to drift to the P-type body region by a reverse electric field, so that the insulated gate bipolar transistor is quickly turned off, and the power consumption of the device is reduced.

Description

Technical Field

[0001] The invention relates to an insulated gate bipolar transistor and a control circuit. Background Art

[0002] High-voltage power semiconductor devices are an important component of power electronics and are widely used in fields such as motor drive in power systems and frequency conversion in consumer electronics. The insulated-gate bipolar transistor (IGBT) is a composite fully controlled voltage-driven power semiconductor device composed of a bipolar junction transistor (BJT) and an insulated gate field effect transistor (MOSFET-MOS). It has the advantages of both the high input impedance of the insulated gate field effect transistor (MOSFET-MOS) and the low on-state voltage drop of the power transistor (Giant Transistor-GTR). The power transistor (Giant Transistor-GTR) has a low saturation voltage drop and a large current density, but a large driving current; the MOSFET has a very small driving power and a fast switching speed, but a large on-state voltage drop and a small current density. The insulated-gate bipolar transistor (IGBT) combines the advantages of the above two devices, with low driving power and low saturation voltage drop. By applying a positive driving voltage to the gate, the internal MOSFET is turned on, thereby forming the base current of the internal PNP transistor, making the insulated-gate bipolar transistor (IGBT) By applying a reverse drive voltage to the gate, the internal MOSFET is turned off, the base current of the internal PNP transistor is cut off, and the insulated-gate bipolar transistor (IGBT) is turned off.

[0003] However, the actual insulated-gate bipolar transistor (IGBT) device cannot achieve the above characteristics. In the control of power semiconductor devices, the switching performance and conduction performance have always been a contradictory relationship. Please refer to Figure 1 and Figure 2In any case, when there is a large on-current, the number of carriers involved in the conduction is large, which will inevitably lead to a large amount of charge being stored in the N-base region. This means that when the device needs to be turned off, it takes a long time to remove these excess carriers from the N-base region, which will cause the phenomenon of tail current, and the turn-off process of the insulated-gate bipolar transistor (IGBT) cannot be completed quickly. During this period, the device has a large current and voltage at the same time, resulting in large switching power consumption, cross conduction, and poor switching performance of the device, especially on devices using freewheeling diodes, the problem is more obvious. Summary of the invention

[0004] The object of the present invention is to provide an insulated gate bipolar transistor which can be quickly turned off to reduce the conduction loss of the device.

[0005] To achieve the above object, the present invention provides the following technical solution: an insulated gate bipolar transistor, comprising a gate structure, an n+ source region, a P-type body region, and a P+ drain injection region, the insulated gate bipolar transistor also comprising an emitter covering the n+ source region, and a collector covering the P+ drain injection region;

[0006] The insulated gate bipolar transistor further comprises an N-base region disposed near the P-type body region, and the gate structure comprises a gate oxide covering the n+ source region, the P-type body region and the N-base region;

[0007] The insulated gate bipolar transistor further includes an isolation layer for isolating the P-type body region from the N-base region, wherein the isolation layer is used to isolate the P-type body region from the N-base region, and then lead the N-base region out as a base control terminal;

[0008] Only when the insulated gate bipolar transistor is turned off, a reverse driving voltage is applied to the gate and a forward driving voltage is applied to the base, so that a reverse bias is formed between the N-base region and the P-type body region, and the holes in the N-base region are accelerated by the reverse electric field to drift to the P-type body region, so that the insulated gate bipolar transistor is quickly turned off.

[0009] Furthermore, the N-base region also includes an N-buffer region, and the N-buffer region is used to reduce the on-state voltage drop of the insulated gate bipolar transistor.

[0010] Furthermore, the N buffer region is arranged between the P+ drain injection region and the N base region.

[0011] Furthermore, the isolation layer is made of insulating material.

[0012] The present invention also provides a control circuit, comprising:

[0013] Control module;

[0014] A controlled module connected to the gate;

[0015] A driving module connected to the control module;

[0016] A unidirectional conduction module connected to the base;

[0017] And an insulated gate bipolar transistor as described in any one of the above; the control module controls the driving module to drive the insulated gate bipolar transistor to turn on and off.

[0018] Furthermore, the driving module includes a first driving unit and a second driving unit, the first driving unit is connected to the gate of the insulated gate bipolar transistor; the second driving unit is connected to the base of the insulated gate bipolar transistor.

[0019] Furthermore, the driving module further includes an inverter connected to the second driving unit, and the inverter is used to invert the output signal of the control module.

[0020] Furthermore, the unidirectional conduction module includes a diode, and the diode is used to ensure that the base control terminal works only when the device is turned off.

[0021] The beneficial effect of the present invention is that by arranging an isolation layer between the P-type body region and the N-base region and a base connected to the N-base region, and applying a reverse driving voltage at the gate and a forward driving voltage at the base, a reverse bias is formed between the N-base region and the P-type body region, and the current-carrying electrons in the N-base region are accelerated by the reverse electric field to drift to the P-type body region, so that the insulated gate bipolar transistor is quickly turned off, thereby reducing the power consumption of the device.

[0022] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a structural diagram of a conventional insulated gate bipolar transistor;

[0024] Figure 2 is the equivalent circuit diagram of a conventional insulated gate bipolar transistor;

[0025] Figure 3 A structural diagram of an insulated gate bipolar transistor shown in the present invention;

[0026] Figure 4 is an equivalent circuit diagram of the insulated gate bipolar transistor shown in the present invention;

[0027] Figure 5It is a schematic diagram of the application of the insulated gate bipolar transistor shown in the present invention in a control circuit;

[0028] Figure 6 for Figure 5 The internal curve diagram of the control circuit shown;

[0029] Figure 7 A curve comparison diagram of the turn-off time of the insulated gate bipolar transistor shown in the present invention and the traditional insulated gate bipolar transistor;

[0030] Figure 8 The schematic diagram of the insulated gate bipolar transistor shown in the present invention is applied to the induction cooker control circuit. DETAILED DESCRIPTION

[0031] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0032] See also Figure 1 and Figure 2 The insulated gate bipolar transistor in a preferred embodiment of the present invention includes a gate structure, an n+ source region, a P-type body region, an N-base region, an N+ buffer region and a P+ drain injection region, wherein the P-type body region, the N-base region and the P+ drain injection region form a PNP bipolar transistor. The N+ buffer region is arranged between the P+ drain injection region and the N-base region. Specifically, the N+ buffer region is arranged at one end close to the P+ drain injection region to reduce the on-state voltage drop of the insulated gate bipolar transistor. The gate structure includes a gate oxide covering the n+ source region, the P-type body region and the N-base region, wherein the gate G is a switch for controlling the device; the insulated gate bipolar transistor also includes an emitter E covering the n+ source region and a collector C covering the P+ drain injection region, and holes are injected into the collector C to perform conduction modulation to reduce the on-state voltage of the device.

[0033] The process of turning on and off the insulated gate bipolar transistor is as follows: by applying a positive driving voltage to the gate G, a channel is formed between the n+ source region and the P-type body region, and the channel is formed on the side close to the gate G. The channel provides the base current for the insulated gate bipolar transistor, making the insulated gate bipolar transistor conductive. At the same time, the P+ drain injection region emits minority carriers to the N-base region, thereby modulating the conductivity of the N-base region, so that the insulated gate bipolar transistor has a strong current-carrying capacity; by applying a reverse driving voltage to the gate G, the channel between the n+ source region and the P-type body region disappears, thereby cutting off the base current and turning off the insulated gate bipolar transistor.

[0034] However, in the above-mentioned turn-off process, when there is a large on-current, the number of carriers participating in the conduction is large, which will inevitably lead to a large amount of charge being stored in the drift region, thus causing the occurrence of the tail current phenomenon. Therefore, please refer to Figure 3 and Figure 4 The insulated gate bipolar transistor in the present invention also includes an isolation layer 5 for isolating the P-type body region from the N-base region. The isolation layer 5 is used to isolate the P-type body region from the N-base region, and then lead the N-base region to control the base B, and the material of the isolation layer 5 is an insulating material. A forward driving voltage is applied to the gate G, a channel is formed between the P-type body region and the gate region, and the device is turned on. After a reverse driving voltage is applied to the gate G, the channel disappears, the device is turned off, and the base B is led out as a new control terminal to control the switch of the device to achieve controllable base region, thereby increasing the density of the device's on-state current, and strengthening the electric field modulation effect in the N-base region, reducing the base resistance of the device, and reducing the on-state voltage drop. At the same time, the electric field can also accelerate the removal of excess carrier holes in the N-base region when the device is to be turned off, thereby greatly shortening the turn-off time of the device and suppressing the tail current phenomenon.

[0035] Specifically, the principle is: while a reverse driving voltage is applied to the gate G, a forward driving voltage is applied to the base region, thereby forming a reverse bias between the N-base region and the P-type body region, and the holes in the N-base region are accelerated by the reverse electric field to drift to the P-type body region, thereby reducing the recombination of holes in the N-base region, so that the insulated gate bipolar transistor is quickly turned off.

[0036] See also Figure 8 In a preferred embodiment, the insulated gate bipolar transistor of the present invention is applied to an induction cooker control circuit. In other embodiments, the insulated gate bipolar transistor of the present invention can also be applied to other devices, which will not be described in detail here.

[0037] When the traditional insulated gate bipolar transistor is applied to the induction cooker control circuit, during the shutdown process of Q1, that is, after the driving voltage on the gate G is pulled down, since Q1 is difficult to shut down quickly, there is a certain voltage difference between the collector C and the emitter E of Q1 and current flows through, which results in Q1 still consuming energy during the resonance process of L2 and C2, increasing the conduction loss of the device and reducing the conversion efficiency of the circuit.

[0038] The induction cooker heating plate comprises a control module 1, a driving module 2 connected to the control module 1, a unidirectional conducting module 4, a controlled module 3 connected to a gate G, and an insulated gate bipolar transistor.

[0039] The control module 1 controls the driving module 2 to drive the insulated gate bipolar transistor to turn on or off, wherein the driving module 2 includes a first driving unit 21 and a second driving unit 22, the first driving unit 21 is connected to the gate G in the insulated gate bipolar transistor, the second driving unit 22 is connected to the base B in the insulated gate bipolar transistor, the driving module 2 also includes an inverter, and the unidirectional conduction module 4 includes a diode D2. For details, see Figure 8 The input end of the inverter is electrically connected to the control module 1, and the output end is electrically connected to the second driving unit 22, so that when the control module 1 outputs a conduction signal, the inverter inverts the conduction signal, thereby making the control signals of the gate G and the base B opposite. For example, when the gate G outputs a high level, the base B outputs a low level, and the insulated gate bipolar transistor is quickly turned on; when the gate G outputs a low level, the base B outputs a high level, thereby reducing the recombination of holes in the N-type drift region, and the insulated gate bipolar transistor is quickly turned off, see Figure 7 The start-off time t1 of the traditional insulated gate bipolar transistor is about 100ns-5000ns, while the start-off time t2 of the insulated gate bipolar transistor can be reduced to about 100ns, thereby significantly reducing its conduction loss.

[0040] See also Figure 5 and Figure 8 The controlled module 3 includes a resonant circuit 31 for adjusting the working efficiency of the induction cooker heating plate, an inductor L1 and a capacitor C1 connected to the resonant circuit 31, a diode D1 and a resistor R1 connected to the collector C and the emitter E of the insulated gate bipolar transistor. Specifically, one end of the diode D1 is connected to the emitter E, and the other end of the diode D1 is connected to the collector C to prevent the current from flowing back; the first end of the inductor L1 is connected to the power supply, the second end of the inductor L1 is connected to the resonant circuit 31, the first end of the capacitor C1 is connected to the resonant circuit 31, and the second end of the capacitor C1 is grounded; one end of the resistor R1 is connected to the emitter E of the insulated gate bipolar transistor, and the other end is grounded.

[0041] In summary: by setting an isolation layer 5 and a base B connected to the N base region between the P-type body region and the N base region, and applying a reverse driving voltage at the gate G and a forward driving voltage to the base B, a reverse bias is formed between the N base region and the P-type body region, and the holes in the N base region are accelerated by the reverse electric field to drift to the P-type body region, so that the insulated gate bipolar transistor is quickly turned off.

[0042] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0043] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An insulated gate bipolar transistor, comprising a gate structure, an n+ source region, a P-type body region, and a P+ drain injection region, the insulated gate bipolar transistor further comprising an emitter covering the n+ source region, and a collector covering the P+ drain injection region; The insulated gate bipolar transistor further comprises an N-base region disposed near the P-type body region, and the gate structure comprises a gate oxide covering the n+ source region, the P-type body region and the N-base region; It is characterized in that The insulated gate bipolar transistor further includes an isolation layer for isolating the P-type body region from the N-base region, wherein the isolation layer is used to isolate the P-type body region from the N-base region, and then lead the N-base region out as a base control terminal; Only when the insulated gate bipolar transistor is turned off, a reverse driving voltage is applied to the gate and a forward driving voltage is applied to the base, so that a reverse bias is formed between the N-base region and the P-type body region, and the holes in the N-base region are accelerated by the reverse electric field to drift to the P-type body region, so that the insulated gate bipolar transistor is quickly turned off.

2. The insulated gate bipolar transistor according to claim 1, wherein: The insulated gate bipolar transistor further includes an N+ buffer zone, and the N+ buffer zone is used to reduce the on-state voltage drop of the insulated gate bipolar transistor.

3. The insulated gate bipolar transistor according to claim 2, wherein: The N+ buffer region is disposed between the P+ drain injection region and the N base region.

4. The insulated gate bipolar transistor according to claim 1, wherein: The isolation layer is made of insulating material.

5. A control circuit, characterized in that: include: Control module; An insulated gate bipolar transistor as claimed in any one of claims 1 to 4; A driving module, comprising an inverter, a first driving unit having two ends respectively connected to the gate of the insulated gate bipolar transistor and the control module, and a second driving unit connected to the base of the insulated gate bipolar transistor, wherein the inverter comprises an input end electrically connected to the control module and an output end electrically connected to the second driving unit; The controlled module includes a resonant circuit for adjusting the working efficiency of an induction cooker heating plate, an inductor and a capacitor connected to the resonant circuit, a diode connected to the collector and emitter of an insulated gate bipolar transistor, and a resistor, one end of the diode is connected to the emitter, the other end of the diode is connected to the collector, the first end of the inductor is connected to a power supply, the second end of the inductor is connected to the resonant circuit, the first end of the capacitor is connected to the resonant circuit, the second end of the capacitor is grounded, the end of the resonant circuit away from the inductor is connected to the collector of the insulated gate bipolar transistor, one end of the resistor is connected to the emitter of the insulated gate bipolar transistor, and the other end is grounded.

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