A reverse-conducting IGCT device

Abstract

The present invention provides a reverse-conducting IGCT device. A P-type fourth doped region with a doping concentration higher than that of the emitter region is provided in the N-type third doped region, and a P-type fifth doped region with a doping concentration higher than that of the fourth doped region is provided in the fourth doped region. When the gate-commutated thyristor is turned on, the trench gate isolation structure controls the channel to turn off. At this time, the fourth doped region and the emitter region are isolated from each other, which will not affect the total doping concentration of the anode of the fast recovery diode, and maintains a low hole extraction speed to ensure a better softness during the reverse recovery process. When the gate-commutated thyristor is turned off, the trench gate isolation structure controls the channel to turn on. At this time, the fourth doped region and the emitter region are connected. At low currents, the fourth doped region first participates in the conduction of the fast recovery diode, and as the current continuously increases, the fifth doped region also successively participates in the conduction, increasing the doping concentration of the P-emitter of the fast recovery diode to varying degrees at different current levels, and improving the surge current resistance of the fast recovery diode.

Description

Technical Field

[0001] The present invention belongs to the field of power semiconductor devices and relates to a reverse-conducting IGCT device. Background Art

[0002] Integrated Gate Commutated Thyristor (IGCT), as an emerging device, plays an important role in high-power power electronic systems. The advantage of IGCT is that it has a conducting state like a thyristor when turned on and a turning-off ability like a transistor when turned off. Traditional IGCT chips cannot conduct in the reverse direction, and a fast recovery diode (FRD) needs to be anti-parallel connected during use, increasing the cost and volume of the system. The reverse-conducting integrated gate commutated thyristor, abbreviated as RC-IGCT, integrates IGCT and FRD on the same chip, having many advantages such as small size, high power density, low cost, and high reliability.

[0003] Since RC-IGCT integrates IGCT and FRD on one chip, in order to ensure the switching performance during chip commutation, it is necessary to prevent the lateral transport of carriers between the P-type doped regions of IGCT and FRD, and an isolation region must be set. However, in fact, the isolation region does not participate in the operation of the device and is a waste of chip area; in addition, IGCT is mainly applied in high-voltage and extra-large current working conditions. Usually, its working current is much larger than that of IGBT modules and MOS devices, and higher requirements are imposed on the reverse recovery characteristics and surge capacity of the diode. The reverse recovery characteristics of the diode are required to be soft recovery to avoid the snappy phenomenon, that is, serious voltage and current oscillations during the turn-off process cause harm to the device and even lead to device failure. In order to ensure the softness of reverse recovery, the injection efficiency of the P region of the diode cannot be too high, which requires a lower doping concentration in the P region of the diode. However, a lower doping concentration in the P region will also lead to a weaker surge current resistance ability and affect its reliability. Summary of the Invention

[0004] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a reverse-conducting IGCT device to solve the problem that the surge current resistance ability of the IGCT device and the reverse recovery softness of the diode in the prior art cannot be effectively compromised.

[0005] To achieve the above object and other related objects, the present invention provides a reverse-conducting IGCT device. The reverse-conducting IGCT device is divided into a GCT region and an FRD region. The reverse-conducting IGCT device includes:

[0006] A first doping region of a first conductivity type, the first doping region includes a base region and an emitter region. The base region is located within the GCT region, and the emitter region is located within the FRD region;

[0007] A second doping region of a second conductivity type is located below the first doping region, wherein a part of the second doping region is located within the GCT region and a part of the second doping region is located within the FRD region;

[0008] A trench gate isolation structure is located between the base region and the emitter region. The trench gate isolation structure includes a groove that penetrates the first doping region and extends into the second doping region. A gate dielectric layer is provided on the sidewalls and the bottom of the groove, and a gate conductive layer is filled in the groove;

[0009] A third doping region of a second conductivity type is located in the emitter region, and the third doping region is in contact with the sidewall of the trench gate isolation structure;

[0010] A fourth doping region of a first conductivity type is located in the third doping region, and the doping concentration of the fourth doping region is greater than the doping concentration of the emitter region;

[0011] A fifth doping region of a first conductivity type is located in the fourth doping region, and the doping concentration of the fifth doping region is greater than the doping concentration of the fourth doping region.

[0012] Optionally, the number of the fifth doping regions is multiple. In a direction away from the trench gate isolation structure, the multiple fifth doping regions are arranged at intervals, wherein the areas of the multiple fifth doping regions gradually decrease, or the areas of the multiple fifth doping regions are the same.

[0013] Optionally, further included are:

[0014] A sixth doping region of a first conductivity type is located below the second doping region and within the GCT region;

[0015] A seventh doping region of a second conductivity type is located below the second doping region and within the FRD region. The doping concentration of the seventh doping region is greater than the doping concentration of the second doping region;

[0016] A first metal layer is located below the sixth doping region and the seventh doping region;

[0017] A second metal layer is located above the emitter region;

[0018] A third metal layer is located above the base region;

[0019] An eighth doping region of a second conductivity type is located above the base region;

[0020] A fourth metal layer is located above the eighth doping region, wherein the fourth metal layer is electrically connected to the second metal layer.

[0021] Optionally, the trench gate isolation structure and the third metal layer are electrically connected.

[0022] Optionally, further comprising:

[0023] An auxiliary trench gate structure, located in the emitter region, the auxiliary trench gate structure includes an auxiliary groove extending from the upper surface of the emitter region into the interior of the emitter region, an auxiliary gate dielectric layer is provided on the sidewall and bottom of the auxiliary groove, and an auxiliary gate conductive layer is filled in the auxiliary groove;

[0024] A ninth doped region of the second conductivity type, located in the emitter region, the ninth doped region is in contact with the sidewall of the auxiliary trench gate structure;

[0025] A tenth doped region of the first conductivity type, located in the ninth doped region, the doping concentration of the tenth doped region is greater than the doping concentration of the emitter region;

[0026] An eleventh doped region of the first conductivity type, located in the tenth doped region, the doping concentration of the eleventh doped region is greater than the doping concentration of the tenth doped region;

[0027] An insulating layer, located between the auxiliary trench gate structure and the second metal layer.

[0028] Optionally, the number of the eleventh doped regions is multiple, and in the direction away from the auxiliary trench gate structure, the multiple eleventh doped regions are arranged at intervals, wherein the areas of the multiple eleventh doped regions gradually decrease, or the areas of the multiple eleventh doped regions are the same.

[0029] Optionally, the insulating layer is a silicon oxide layer.

[0030] Optionally, the trench gate isolation structure, the auxiliary trench gate structure and the third metal layer are electrically connected.

[0031] Optionally, the first conductivity type is P-type and the second conductivity type is N-type; or the first conductivity type is N-type and the second conductivity type is P-type.

[0032] Optionally, the N-type is formed by doping with VA group elements, and the P-type is formed by doping with IIIA group elements.

[0033] As described above, in the reverse-conducting IGCT device of the present invention, the GCT region and the FRD region are isolated by a trench gate isolation structure to improve the switching efficiency. Moreover, an N-type third doped region is provided in the P-type emitter region, a P-type fourth doped region with a doping concentration higher than that of the emitter region is provided in the N-type third doped region, and a P-type fifth doped region with a doping concentration higher than that of the fourth doped region is provided in the fourth doped region. When the gate-commutated thyristor is turned on, the trench gate isolation structure controls the channel to turn off. At this time, the fourth doped region and the emitter region are isolated, which will not affect the total doping concentration of the anode of the fast recovery diode and maintain a low hole extraction speed to ensure a better softness in the reverse recovery process. When the gate-commutated thyristor is turned off, the trench gate isolation structure controls the channel to turn on. At this time, the fourth doped region and the emitter region are connected. At a small current, the fourth doped region first participates in the conduction of the fast recovery diode. As the current continuously increases, the fifth doped region also successively participates in the conduction, improving the doping concentration of the P-emitter of the fast recovery diode to varying degrees at different current levels, so that a large injection efficiency of the emitter region is maintained at a large current, and a small emission efficiency of the emitter region is provided at a small current, improving the surge current resistance of the fast recovery diode while taking into account the reverse recovery characteristics. In addition, a plurality of fifth doped regions with different areas are provided, and different numbers of fifth doped regions are turned on at different currents, further improving the surge current resistance of the fast recovery diode while taking into account the reverse recovery characteristics. Description of the Drawings

[0034] Figure 1 It shows a schematic diagram of the reverse-conducting IGCT device in the first embodiment of the present invention.

[0035] Figure 2 It shows a schematic diagram of the reverse-conducting IGCT device in the second embodiment of the present invention.

[0036] Description of Component Labels: 1 - GCT region; 2 - FRD region; 3 - First doped region, 300 - Base region, 301 - Emitter region; 4 - Second doped region; 5 - Trench gate isolation structure, 500 - Gate dielectric layer, 501 - Gate conductive layer; 6 - Third doped region; 7 - Fourth doped region; 8 - Fifth doped region; 9 - Sixth doped region; 10 - Seventh doped region; 11 - First metal layer; 12 - Second metal layer; 13 - Third metal layer; 14 - Eighth doped region; 15 - Fourth metal layer; 16 - Auxiliary trench gate structure, 1600 - Auxiliary gate dielectric layer, 1601 - Auxiliary gate conductive layer; 17 - Ninth doped region; 18 - Tenth doped region; 19 - Eleventh doped region; 20 - Insulating layer. Detailed Embodiments

[0037] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand the other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0038] Please refer to Figure 1 and Figure 2 . It should be noted that the diagrams provided in this embodiment only illustrate the basic concept of the present invention in a schematic manner. Therefore, only the components related to the present invention are shown in the diagrams, rather than being drawn according to the number, shape, and size of the components in actual implementation. The type, quantity, and ratio of each component in actual implementation can be arbitrarily changed, and the component layout type may also be more complex.

[0039] Embodiment 1

[0040] This embodiment provides a reverse-conducting IGCT device. Please refer to Figure 1 . The reverse-conducting IGCT device is divided into a GCT region 1 and an FRD region 2. The reverse-conducting IGCT device includes a first doped region 3 of a first conductivity type, a second doped region 4 of a second conductivity type, a trench gate isolation structure 5, a third doped region 6 of a second conductivity type, a fourth doped region 7 of a first conductivity type, and a fifth doped region 8 of a first conductivity type. The first doped region 3 includes a base region 300 and an emitter region 301. The base region 300 is located in the GCT region 1, and the emitter region 301 is located in the FRD region 2. The second doped region 4 is located below the first doped region 3. Among them, a part of the second doped region 4 is located in the GCT region 1, and a part of the second doped region 4 is located in the FRD region 2. The trench gate isolation structure 5 is located between the base region 300 and the emitter region 301. The trench gate isolation structure 5 includes a groove that penetrates the first doped region 3 and extends into the second doped region 4. The side wall and bottom of the groove are provided with a gate dielectric layer 500, and the groove is filled with a gate conductive layer 501. The third doped region 6 is located in the emitter region 301, and the third doped region 6 is in contact with the side wall of the trench gate isolation structure 5. The fourth doped region 7 is located in the third doped region 6, and the doping concentration of the fourth doped region 7 is greater than the doping concentration of the emitter region 301. The fifth doped region 8 is located in the fourth doped region 7, and the doping concentration of the fifth doped region 8 is greater than the doping concentration of the fourth doped region 7.

[0041] As an example, the GCT region 1 is a gate-commutated thyristor region, and the FRD region 2 is a fast-recovery diode region.

[0042] As an example, in this embodiment, the first conduction type is P-type and the second conduction type is N-type; in another example, the first conduction type is N-type and the second conduction type is P-type, which can be selected according to requirements. Among them, the P-type is a conduction type formed by doping with group IIIA elements, and the N-type is a conduction type formed by doping with group VA elements.

[0043] As an example, the P-type base region 300 is the base region of the gate-commutated thyristor, and the P-type emitter region 301 is the emitter region of the fast-recovery diode.

[0044] As an example, the N-type second doped region 4 located within the GCT region 1 serves as the drift region of the gate-commutated thyristor, and the N-type second doped region 4 located within the FRD region 2 serves as the drift region of the fast-recovery diode.

[0045] As an example, the trench gate isolation structure 5 is located between the base region 300 and the emitter region 301 and extends into the second doped region 4 to isolate the base region 300 and the emitter region 301, thereby isolating the gate-commutated thyristor and the fast-recovery diode. Compared with the prior art where a PNP junction is used to isolate the gate-commutated thyristor and the fast-recovery diode, resulting in a curved surface junction at the edge of the P-type doped region in the GCT working region and the FRD working region, where the electric field is more likely to concentrate here, causing the device to break down prematurely. In this application, the trench gate isolation structure 5 is used to isolate the gate-commutated thyristor and the fast-recovery diode, which can ensure that the PN junctions in the GCT working region and the FRD working region are both planar junctions, having better blocking ability.

[0046] As an example, the material of the gate dielectric layer 500 is silicon oxide, and the material of the gate conductive layer 501 is polysilicon.

[0047] As an example, the doping concentration of the P-type fourth doped region 7 is greater than that of the P-type emitter region 301, and the N-type third doped region 6 separates the fourth doped region 7 and the emitter region 301.

[0048] As an example, the doping concentration of the P-type fifth doped region 8 is greater than that of the P-type fourth doped region 7.

[0049] As an example, the third doped region 6 in contact with the sidewall of the trench gate isolation structure 5 serves as a channel, and the trench gate isolation structure 5 controls the opening or closing of the channel.

[0050] As an example, when the gate commutated thyristor is turned on, the trench gate isolation structure 5 controls the channel to turn off. At this time, the fourth doping region 7 and the emitter region 301 are isolated, which will not affect the total doping concentration of the anode of the fast recovery diode, and maintains a low hole extraction speed to ensure a better softness during the reverse recovery process.

[0051] As an example, when the gate commutated thyristor is turned off, the trench gate isolation structure 5 controls the channel to turn on. At this time, the fourth doping region 7 and the emitter region 301 are connected, and a fifth doping region 8 with a higher doping concentration is arranged in the fourth doping region 7. At low currents, the fourth doping region 7 first participates in the conduction of the fast recovery diode. As the current continuously increases, the fifth doping region 8 also successively participates in the conduction, which is equivalent to increasing the doping concentration of the P-emitter of the fast recovery diode to different degrees at different current levels, enabling it to have different hole injection efficiencies, improving the surge current resistance ability of the fast recovery diode while taking into account the reverse recovery characteristics, that is, ensuring a low total anode emission efficiency under the condition of small current turn-off in the FRD region, which poses a great challenge to the reverse recovery softness, and ensuring a high total anode emission efficiency under the condition of large current turn-on, which poses a great challenge to reliability. At different current levels, the corresponding total anode emission efficiency is matched differently, improving the trade-off between the surge resistance ability and the reverse recovery softness, and at the same time meeting the requirements of the reverse recovery softness and reliability.

[0052] Specifically, there is a potential barrier between the fifth doping region 8 and the fourth doping region 7. At low currents, the lateral voltage drop is not sufficient to overcome the potential barrier, and electrons will preferentially pass through the fourth doping region 7; at large currents, the lateral voltage drop can overcome the potential barrier, and the fifth doping region 8 will conduct and participate in the conduction.

[0053] As an example, the number of the fifth doping regions 8 is multiple. In the direction away from the trench gate isolation structure 5, the multiple fifth doping regions 8 are arranged at intervals, and among them, the areas (lateral widths) of the multiple fifth doping regions 8 gradually decrease, so that different numbers of the fifth doping regions 8 can be conducted at different currents, further improving the surge current resistance ability of the fast recovery diode while taking into account the reverse recovery characteristics; of course, in another example, the areas (lateral widths) of the multiple fifth doping regions 8 can also be set to be the same, and all the fifth doping regions 8 are conducted at the same current, which can be selected according to requirements.

[0054] As an example, the reverse conducting IGCT device further includes:

[0055] A sixth doping region 9 of the first conductivity type, located below the second doping region 4 and within the GCT region 1, where the sixth doping region 9 is a lightly doped P-type and has a relatively thin thickness, serving as the P-type transparent anode region of the gate commutated thyristor;

[0056] The seventh doping region 10 of the second conductivity type is located below the second doping region 4, and the seventh doping region 10 is located within the FRD region 2. Among them, the seventh doping region 10 is N-type heavily doped and serves as the N+ buffer zone of the fast recovery diode.

[0057] The first metal layer 11 is located below the sixth doping region 9 and the seventh doping region 10. Among them, the first metal layer 11 located below the sixth doping region 9 serves as the anode metal layer of the gate commutated thyristor, and the first metal layer 11 located below the seventh doping region 10 serves as the cathode metal layer of the fast recovery diode.

[0058] The second metal layer 12 is located above the emitter region 301, and the second metal layer 12 serves as the anode metal layer of the fast recovery diode.

[0059] The third metal layer 13 is located above the base region 300, and the third metal layer 13 serves as the gate of the gate commutated thyristor.

[0060] The eighth doping region 14 of the second conductivity type is located above the base region 300, and the eighth doping region 14 serves as the N-type cathode region of the gate commutated thyristor.

[0061] The fourth metal layer 15 is located above the eighth doping region 14, and the fourth metal layer 15 serves as the cathode metal layer of the gate commutated thyristor.

[0062] As an example, the anode metal layer of the gate commutated thyristor is electrically connected to the cathode metal layer of the fast recovery diode, and the cathode metal layer of the gate commutated thyristor is electrically connected to the anode metal layer of the fast recovery diode, that is, the gate commutated thyristor and the fast recovery diode are anti-parallel connected.

[0063] As an example, in the present application, the trench gate isolation structure 5 and the third metal layer 13 are connected to the same metal layer and can be controlled with only the same potential, without the need for separate gate voltage control for the trench gate isolation structure 5, which simplifies the device structure and saves costs. When the gate commutated thyristor is turned on, the third metal layer 13 (gate) is subjected to a positive voltage, and the base region 300 (P) is subjected to positive current injection. Holes flow to the eighth doped region 14 (N), and electrons flow to the second doped region 4 (N). The space charge region of the reverse-biased PN junction originally formed between the base region 300 (P) and the eighth doped region 14 (N) is neutralized, and the current of the other two PN junctions is enhanced. The gate commutated thyristor is turned on, and the trench gate isolation structure 5 cannot turn on the channel under the action of the positive voltage, so it only serves to isolate the gate commutated thyristor and the fast recovery diode; when the gate commutated thyristor is turned off, the third metal layer 13 (gate) is subjected to a negative voltage, and the trench gate isolation structure 5 turns on the channel under the action of the negative voltage. At this time, the fourth doped region 7 and the emitter region 301 are connected.

[0064] As an example, in another example, the trench gate isolation structure 5 can also be integrated into the drive control circuit as a single electrode and selected according to actual requirements.

[0065] As described above, in the reverse-conducting IGCT device of this embodiment, the GCT region and the FRD region are isolated by the trench gate isolation structure, improving the switching efficiency; and, an N-type third doped region is provided in the P-type emitter region, a P-type fourth doped region with a doping concentration higher than that of the emitter region is provided in the N-type third doped region, and a P-type fifth doped region with a doping concentration higher than that of the fourth doped region is provided in the fourth doped region. When the gate commutated thyristor is turned on, the trench gate isolation structure controls the channel to turn off. At this time, the fourth doped region and the emitter region are separated, and the total doping concentration of the anode of the fast recovery diode is not affected, maintaining a low hole extraction speed to ensure a better softness during the reverse recovery process. When the gate commutated thyristor is turned off, the trench gate isolation structure controls the channel to turn on. At this time, the fourth doped region and the emitter region are connected. At low currents, the fourth doped region first participates in the conduction of the fast recovery diode, and as the current continuously increases, the fifth doped region also successively participates in the conduction, increasing the doping concentration of the P-emitter of the fast recovery diode to varying degrees at different current levels, so that a large injection efficiency of the emitter region is maintained at high currents, and a small emission efficiency of the emitter region is provided at low currents, improving the surge current resistance of the fast recovery diode while taking into account the reverse recovery characteristics; in addition, fifth doped regions with different areas are provided, and different numbers of fifth doped regions are turned on at different currents, further improving the surge current resistance of the fast recovery diode while taking into account the reverse recovery characteristics.

[0066] Embodiment 2

[0067] This embodiment provides a reverse-conducting IGCT device. Please refer to Figure 2 The difference between the reverse-conducting IGCT device of this embodiment and the reverse-conducting IGCT device described in Embodiment 1 is that: the reverse-conducting IGCT device of this embodiment further includes an auxiliary trench gate structure 16, a ninth doping region 17 of the second conductivity type, a tenth doping region 18 of the first conductivity type, an eleventh doping region 19 of the first conductivity type, and an insulating layer 20.

[0068] As an example, the auxiliary trench gate structure 16 is located in the emitter region 301. The auxiliary trench gate structure 16 includes an auxiliary groove extending from the upper surface of the emitter region 301 to the inside of the emitter region 301. An auxiliary gate dielectric layer 1600 is provided on the side wall and bottom of the auxiliary groove, and an auxiliary gate conductive layer 1601 is filled in the auxiliary groove; wherein, the material of the auxiliary gate dielectric layer 1600 is silicon oxide, and the material of the auxiliary gate conductive layer 1601 is polysilicon.

[0069] As an example, the number of the auxiliary trench gate structures 16 is multiple. In this embodiment, a part of the auxiliary trench gate structures 16 is located directly below the second metal layer 12, and a part of the auxiliary trench gate structures 16 is not directly below the second metal layer 12; in another example, all of the multiple auxiliary trench gate structures 16 are directly below the second metal layer 12, or all of the multiple auxiliary trench gate structures 16 are not directly below the second metal layer 12, which can be selected according to requirements.

[0070] As an example, the N-type ninth doping region 17 is located in the emitter region 301, and the ninth doping region 17 is in contact with the side wall of the auxiliary trench gate structure 16.

[0071] As an example, in the auxiliary trench gate structure 16 closest to the trench gate isolation structure 5, the N-type ninth doping region 17 and the N-type third doping region 6 share the same doping region.

[0072] As an example, the P-type tenth doping region 18 is located in the ninth doping region 17. The doping concentration of the tenth doping region 18 is greater than the doping concentration of the emitter region 301, and the ninth doping region 17 isolates the tenth doping region 18 from the emitter region 301.

[0073] As an example, the ninth doping region 17 in contact with the side wall of the auxiliary trench gate structure 16 serves as a channel, and the auxiliary trench gate structure 16 controls the opening or closing of the channel.

[0074] As an example, the P-type eleventh doping region 19 is located in the P-type tenth doping region 18, and the doping concentration of the eleventh doping region 19 is greater than the doping concentration of the tenth doping region 18.

[0075] As an example, when the gate-commutated thyristor is turned on, the trench gate isolation structure 5 controls the channel turn-off of the third doped region 6, and the auxiliary trench gate structure 16 controls the trench turn-off of the ninth doped region 17.

[0076] As an example, when the gate-commutated thyristor is turned off, the trench gate isolation structure 5 controls the channel turn-on of the third doped region 6, and the auxiliary trench gate structure 16 controls the trench turn-on of the ninth doped region 17. At low currents, the fourth doped region 7 and the tenth doped region 18 first participate in the conduction of the fast recovery diode. As the current continuously increases, the fifth doped region 8 and the eleventh doped region 19 also successively participate in the conduction, improving the surge resistance of the device at high currents and the reverse recovery softness at low currents.

[0077] As an example, the trench gate isolation structure 5, the auxiliary trench gate structure 16, and the third metal layer 13 are electrically connected using the same metal layer. In other examples, the auxiliary trench gate structure 16 can also be integrated as a single electrode in the drive control circuit and selected according to actual requirements.

[0078] As an example, the number of the eleventh doped regions 19 is multiple. In the direction away from the auxiliary trench gate structure 16, the multiple eleventh doped regions 19 are arranged at intervals. Among them, in the direction away from the auxiliary trench gate structure 16, the area (lateral width) of the multiple eleventh doped regions 19 gradually decreases, or the area (lateral width) of the multiple eleventh doped regions 19 is the same, and the selection is made according to requirements.

[0079] As an example, the insulating layer 20 is located between the auxiliary trench gate structure 16 and the second metal layer 12 and is used to insulate and isolate the auxiliary trench gate structure 16 and the second metal layer 12. Among them, the material of the insulating layer 20 includes silicon oxide.

[0080] In summary, in the reverse-conducting IGCT device of the present invention, the GCT region and the FRD region are isolated by a trench gate isolation structure, improving the switching efficiency; moreover, an N-type third doping region is provided in the P-type emitter region, a P-type fourth doping region with a doping concentration higher than that of the emitter region is provided in the third doping region, and a P-type fifth doping region with a doping concentration higher than that of the fourth emitter region is provided in the fourth doping region. When the gate-commutated thyristor is turned on, the trench gate isolation structure controls the channel to turn off. At this time, the fourth doping region and the emitter region are isolated, which will not affect the total doping concentration of the anode of the fast recovery diode and maintain a low hole extraction speed to ensure a better softness during the reverse recovery process. When the gate-commutated thyristor is turned off, the trench gate isolation structure controls the channel to turn on. At this time, the fourth doping region and the emitter region are connected. At a small current, the fourth doping region first participates in the conduction of the fast recovery diode, and as the current continuously increases, the fifth doping region also successively participates in the conduction, improving the doping concentration of the P-emitter of the fast recovery diode to varying degrees at different current levels, so that a large injection efficiency of the emitter region is maintained at a large current, and a small emission efficiency of the emitter region is achieved at a small current, improving the surge current resistance of the fast recovery diode while taking into account the reverse recovery characteristics; in addition, a plurality of fifth doping regions with different areas are provided, and different numbers of fifth doping regions are turned on at different currents, further improving the surge current resistance of the fast recovery diode while taking into account the reverse recovery characteristics. Therefore, the present invention effectively overcomes various disadvantages in the prior art and has high industrial utilization value.

[0081] The above embodiments are only illustrative of the principles and effects of the present invention and are not intended to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A reverse conducting IGCT device, the reverse conducting IGCT device is divided into a GCT region and an FRD region, characterized in that: The reverse conducting IGCT device comprises: A first doping region of a first conductivity type, the first doping region comprising a base region and an emitter region, the base region is located in the GCT region, and the emitter region is located in the FRD region; A second doping region of a second conductivity type, located below the first doping region, wherein a portion of the second doping region is located in the GCT region, and a portion of the second doping region is located in the FRD region; a trench gate isolation structure, located between the base region and the emitter region, the trench gate isolation structure comprising a groove penetrating the first doping region and extending into the second doping region, a gate dielectric layer being provided on the sidewall and the bottom of the groove, and a gate conductive layer being filled in the groove; A third doping region of the second conductivity type is located in the emitter region, and the third doping region is in contact with a sidewall of the trench gate isolation structure; a fourth doping region of the first conductivity type, located in the third doping region, the doping concentration of the fourth doping region being greater than the doping concentration of the emitter region, and the fourth doping region being in contact with a sidewall of the trench gate isolation structure; A fifth doping region of the first conductivity type is located in the fourth doping region, and a doping concentration of the fifth doping region is greater than a doping concentration of the fourth doping region.

2. The reverse conducting IGCT device according to claim 1, characterized in that: There are multiple fifth doping regions, and the multiple fifth doping regions are arranged at intervals in a direction away from the trench gate isolation structure, wherein the areas of the multiple fifth doping regions gradually decrease, or the areas of the multiple fifth doping regions are the same.

3. The reverse conducting IGCT device according to claim 1, characterized in that: Also includes: a sixth doping region of the first conductivity type, located below the second doping region, and the sixth doping region is located in the GCT region; A seventh doping region of the second conductivity type, located below the second doping region, and the seventh doping region is located in the FRD region, and the doping concentration of the seventh doping region is greater than the doping concentration of the second doping region; A first metal layer, located below the sixth doping region and the seventh doping region; A second metal layer, located above the emission region; A third metal layer, located above the base region; an eighth doping region of the second conductivity type, located above the base region; A fourth metal layer is located above the eighth doped region, wherein the fourth metal layer is electrically connected to the second metal layer.

4. The reverse conducting IGCT device according to claim 3, characterized in that: The trench gate isolation structure is electrically connected to the third metal layer.

5. The reverse conducting IGCT device according to claim 3, characterized in that: Also includes: An auxiliary trench gate structure is located in the emitter region, the auxiliary trench gate structure comprises an auxiliary groove extending from the upper surface of the emitter region to the inside of the emitter region, the sidewall and bottom of the auxiliary groove are provided with an auxiliary gate dielectric layer, and the auxiliary groove is filled with an auxiliary gate conductive layer; a ninth doping region of the second conductivity type, located in the emitter region, the ninth doping region being in contact with a sidewall of the auxiliary trench gate structure; a tenth doping region of the first conductivity type, located in the ninth doping region, wherein the doping concentration of the tenth doping region is greater than the doping concentration of the emission region; an eleventh doping region of the first conductivity type, located in the tenth doping region, wherein the doping concentration of the eleventh doping region is greater than the doping concentration of the tenth doping region; An insulating layer is located between the auxiliary trench gate structure and the second metal layer.

6. The reverse conducting IGCT device according to claim 5, characterized in that: There are multiple eleventh doping regions, and the multiple eleventh doping regions are arranged at intervals in a direction away from the auxiliary trench gate structure, wherein the areas of the multiple eleventh doping regions gradually decrease, or the areas of the multiple eleventh doping regions are the same.

7. The reverse conducting IGCT device according to claim 5, characterized in that: The insulating layer is a silicon oxide layer.

8. The reverse conducting IGCT device according to claim 5, characterized in that: The trench gate isolation structure, the auxiliary trench gate structure and the third metal layer are electrically connected.

9. The reverse conducting IGCT device according to claim 1, characterized in that: The first conductivity type is P type, and the second conductivity type is N type; or the first conductivity type is N type, and the second conductivity type is P type.

10. The reverse conducting IGCT device according to claim 9, characterized in that: The N-type is formed by doping with group VA elements, and the P-type is formed by doping with group IIIA elements.

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