Reverse conducting IGCT device

Abstract

According to the reverse conducting IGCT device, a P-type fourth doped region with the doping concentration larger than that of an emitter region is arranged in an N-type third doped region, a P-type fifth doped region with the doping concentration larger than that of the fourth doped region is arranged in the fourth doped region, when a gate commutated thyristor is switched on, a trench gate isolation structure controls a channel to be switched off, and when a gate commutated thyristor is switched on, a trench gate isolation structure controls a trench to be switched off; when the gate commutated thyristor is switched off, the trench gate isolation structure controls the channel to be opened, the fourth doped region is communicated with the emitter region, and the fourth doped region is separated from the emitter region, so that the total doping concentration of the anode of the fast recovery diode is not affected, and a relatively low hole extraction speed is kept, and therefore, the reverse recovery process can be ensured to have better softness. The fourth doped region firstly participates in the conduction of the fast recovery diode under low current, and the fifth doped region also participates in the conduction successively along with the continuous increase of the current, so that the doping concentration of the P emitter of the fast recovery diode is improved to different degrees under different current levels, and the surge current resistance of the fast recovery diode is improved.

Description

Technical Field

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

[0002] As an emerging device, integrated gate-commutated thyristor (IGCT) plays an important role in high-power power electronic systems. The advantage of IGCT is that it has the same conduction state as thyristor when turned on and the same shutdown ability as transistor when turned off. Traditional IGCT chips cannot conduct in reverse, and a fast recovery diode (FRD) needs to be connected in reverse parallel when used, which increases the cost and volume of the system. The reverse-conducting integrated gate-commutated thyristor, referred to as RC-IGCT, integrates IGCT and FRD on the same chip, and has many advantages such as small size, high power density, low cost, and high reliability.

[0003] Since RC-IGCT integrates IGCT and FRD on a chip, an isolation area must be set to prevent the lateral transmission of carriers between the P-type doped regions of IGCT and FRD to ensure the switching performance when the chip is commutated. However, in fact, the isolation area does not participate in the operation of the device, which is a waste of chip area. In addition, IGCT is mainly used under high-voltage and ultra-high current conditions. Usually, its operating current is much larger than that of IGBT modules and MOS devices, and has higher requirements for 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, the serious voltage and current oscillations generated during the shutdown process will harm the device and even cause the device to fail. In order to ensure the reverse recovery softness, the injection efficiency of the diode P region cannot be too high, which requires a low doping concentration in the diode P region, but a low P region doping concentration will weaken the surge current resistance and affect its reliability. Summary of the invention

[0004] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a reverse-conducting IGCT device for solving the problem in the prior art that the surge current resistance capability of the IGCT device and the reverse recovery softness of the diode cannot be effectively compromised.

[0005] In order to achieve the above-mentioned object and other related objects, the present invention provides a reverse conducting type IGCT device, wherein the reverse conducting type IGCT device is divided into a GCT region and an FRD region, and the reverse conducting type 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, wherein the doping concentration of the fourth doping region is greater than the doping concentration of the emission region; 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.

[0006] Optionally, 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 areas of the multiple fifth doping regions gradually decrease, or areas of the multiple fifth doping regions are the same.

[0007] Optionally, it 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.

[0008] Optionally, the trench gate isolation structure and the third metal layer are electrically connected.

[0009] Optionally, it 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.

[0010] Optionally, 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 areas of the multiple eleventh doping regions gradually decrease, or areas of the multiple eleventh doping regions are the same.

[0011] Optionally, the insulating layer is a silicon oxide layer.

[0012] Optionally, the trench gate isolation structure, the auxiliary trench gate structure and the third metal layer are electrically connected.

[0013] 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.

[0014] Optionally, the N-type is formed by doping with group VA elements, and the P-type is formed by doping with group IIIA elements.

[0015] 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; and an N-type third doping region is arranged in the P-type emitter region, a P-type fourth doping region with a doping concentration greater than that of the emitter region is arranged in the N-type third doping region, and a P-type fifth doping region with a doping concentration greater than that of the fourth doping region is arranged in the fourth doping region. When the gate-commutated thyristor is turned on, the trench gate isolation structure controls the channel to be turned 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 a low hole extraction speed is maintained to ensure that the reverse recovery process has better softness. When the gate-commutated thyristor is turned off, the trench gate isolation structure controls the channel to be turned off. The structure controls the opening of the channel. At this time, the fourth doped region and the emitter region are connected. Under low current, the fourth doped region first participates in the conduction of the fast recovery diode. As the current continues to increase, the fifth doped region also participates in the conduction successively. The doping concentration of the emitter P of the fast recovery diode is increased to different degrees under different current levels, so that the injection efficiency of the emitter region is maintained at a large level under high current, and the emitter region has a small emission efficiency under low current, thereby improving the ability of the fast recovery diode to resist surge current while taking into account the reverse recovery characteristics; in addition, multiple fifth doped regions with different areas are set, and different numbers of fifth doped regions are turned on under different currents, thereby further improving the ability of the fast recovery diode to resist surge current while taking into account the reverse recovery characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It shows a schematic diagram of a reverse conducting IGCT device in the first embodiment of the present invention.

[0017] Figure 2 It shows a schematic diagram of a reverse conducting IGCT device in the second embodiment of the present invention.

[0018] Component number explanation: 1-GCT region; 2-FRD region; 3-first doping region, 300-base region, 301-emitter region; 4-second doping region; 5-trench gate isolation structure, 500-gate dielectric layer, 501-gate conductive layer; 6-third doping region; 7-fourth doping region; 8-fifth doping region; 9-sixth doping region; 10-seventh doping region; 11-first metal layer; 12-second metal layer; 13-third metal layer; 14-eighth doping region; 15-fourth metal layer; 16-auxiliary trench gate structure, 1600-auxiliary gate dielectric layer, 1601-auxiliary gate conductive layer; 17-ninth doping region; 18-tenth doping region; 19-eleventh doping region; 20-insulating layer. DETAILED DESCRIPTION

[0019] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.

[0020] See also Figure 1 and Figure 2 It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0021] Embodiment 1

[0022] This embodiment provides a reverse-conducting IGCT device. 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 doping region 3 of a first conductivity type, a second doping region 4 of a second conductivity type, a trench gate isolation structure 5, a third doping region 6 of a second conductivity type, a fourth doping region 7 of a first conductivity type, and a fifth doping region 8 of a first conductivity type. The first doping 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 doping region 4 is located below the first doping region 3, wherein a portion of the second doping region 4 is located in the GCT region 1, and a portion of the second doping 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 doping region 3 and extends to the second doping region 4, the sidewall 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 doping region 6 is located in the emitter region 301, the third doping region 6 is in contact with the sidewall of the trench gate isolation structure 5; the fourth doping region 7 is located in the third doping region 6, and the concentration of the fourth doping region 7 is greater than the doping concentration of the emitter region 301; the fifth doping region 8 is located in the fourth doping region 7, and the doping concentration of the fifth doping region 8 is greater than the doping concentration of the fourth doping region 7.

[0023] As an example, the GCT region 1 is a gate commutated thyristor region, and the FRD region 2 is a fast recovery diode region.

[0024] As an example, in this embodiment, the first conductivity type is P type, and the second conductivity type is N type; in another example, the first conductivity type is N type, and the second conductivity type is P type, which can be selected according to the requirements. Among them, P type is a conductivity type formed by doping with IIIA group elements, and N type is a conductivity type formed by doping with VA group elements.

[0025] As an example, the P-type base region 300 is a base region of a gate-commutated thyristor, and the P-type emitter region 301 is an emitter region of a fast recovery diode.

[0026] As an example, the N-type second doped region 4 located in the GCT region 1 is used as a drift region of a gate commutated thyristor, and the N-type second doped region 4 located in the FRD region 2 is used as a drift region of a fast recovery diode.

[0027] 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, and is used to isolate the base region 300 from the emitter region 301, and further isolate the gate commutated thyristor from the fast recovery diode. Compared with the prior art that uses a PNP junction to isolate the gate commutated thyristor from the fast recovery diode, resulting in the edge of the P-type doped region of the GCT working area and the FRD working area being a curved junction, the electric field is more likely to be concentrated there, causing the device to break down prematurely, the trench gate isolation structure 5 is used in the present application to isolate the gate commutated thyristor from the fast recovery diode, which can ensure that the PN junctions of the GCT working area and the FRD working area are both planar junctions, and have better blocking capabilities.

[0028] As an example, the gate dielectric layer 500 is made of silicon oxide, and the gate conductive layer 501 is made of polysilicon.

[0029] As an example, the doping concentration of the P-type fourth doping region 7 is greater than the doping concentration of the P-type emitter region 301 , and the N-type third doping region 6 isolates the fourth doping region 7 from the emitter region 301 .

[0030] As an example, the doping concentration of the P-type fifth doping region 8 is greater than the doping concentration of the P-type fourth doping region 7 .

[0031] As an example, the third doping 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.

[0032] As an example, when the gate-commutated thyristor is turned on, the trench gate isolation structure 5 controls the channel to be turned 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 maintain a low hole extraction speed to ensure that the reverse recovery process has better softness.

[0033] As an example, when the gate-commutated thyristor is turned off, the trench gate isolation structure 5 controls the channel to open. At this time, the fourth doping region 7 is connected to the emitter region 301, and a fifth doping region 8 with a higher doping concentration is set in the fourth doping region 7. Under low current, the fourth doping region 7 first participates in the conduction of the fast recovery diode. As the current continues to increase, the fifth doping region 8 also successively participates in the conduction, which is equivalent to increasing the doping concentration of the emitter of the fast recovery diode P to different degrees under different current levels, so that it has different hole injection efficiencies, improving the fast recovery diode's ability to resist surge current while taking into account the reverse recovery characteristics, that is, when the FRD region is turned off at a small current, which poses a great challenge to the reverse recovery softness, a low anode total emission efficiency is guaranteed, and when the FRD region is turned on at a large current, which poses a great challenge to the reliability, a high anode total emission efficiency is guaranteed. Different anode total emission efficiencies are matched accordingly under different current levels, thereby improving the compromise between surge resistance and reverse recovery softness, and meeting the requirements of reverse recovery softness and reliability.

[0034] Specifically, there is a potential barrier between the fifth doping region 8 and the fourth doping region 7. When the current is small, the lateral voltage drop is not enough to overcome the potential barrier, and electrons will preferentially go through the fourth doping region 7; when the current is large, the lateral voltage drop can overcome the potential barrier, and the fifth doping region 8 will be turned on and participate in conduction.

[0035] As an example, there are multiple fifth doping regions 8, and the multiple fifth doping regions 8 are arranged at intervals in the direction away from the trench gate isolation structure 5, wherein the areas (lateral widths) of the multiple fifth doping regions 8 gradually decrease, and different numbers of the fifth doping regions 8 can be turned on under different currents, thereby further improving the fast recovery diode's ability to resist surge current 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 of the fifth doping regions 8 are turned on under the same current, and selection is made according to needs.

[0036] As an example, the reverse conducting IGCT device further includes: A sixth doping region 9 of the first conductivity type, located below the second doping region 4, and the sixth doping region 9 is located in the GCT region 1, wherein the sixth doping region 9 is lightly P-type doped and thin, and serves as a P-type transparent anode region of the gate-commutated thyristor; A seventh doping region 10 of the second conductivity type, located below the second doping region 4, and the seventh doping region 10 is located in the FRD region 2, wherein the seventh doping region 10 is N-type heavily doped and serves as an N+ buffer region of a fast recovery diode; A first metal layer 11 is located below the sixth doping region 9 and the seventh doping region 10, wherein the first metal layer 11 located below the sixth doping region 9 serves as an anode metal layer of a gate-commutated thyristor, and the first metal layer 11 located below the seventh doping region 10 serves as a cathode metal layer of a fast recovery diode; A second metal layer 12, located above the emitter region 301, the second metal layer 12 serves as an anode metal layer of a fast recovery diode; A third metal layer 13, located above the base region 300, the third metal layer 13 serving as a gate of the gate-commutated thyristor; An eighth doping region 14 of the second conductivity type, located above the base region 300, the eighth doping region 14 serving as an N-type cathode region of the gate-commutated thyristor; The fourth metal layer 15 is located above the eighth doping region 14 , and the fourth metal layer 15 serves as a cathode metal layer of the gate-commutated thyristor.

[0037] 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.

[0038] 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 only require the same potential to be controlled. There is no need to perform gate voltage control for the trench gate isolation structure 5 separately, 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 positive voltage, the base region 300 (P) is injected with positive current, holes flow to the eighth doped region 14 (N), and electrons flow to the second doped region 4 (N). The reverse biased PN junction space charge region originally formed by the base region 300 (P) and the eighth doped region 14 (N) is neutralized, and the currents of the remaining two PN junctions are strengthened. The gate-commutated thyristor is turned on, and the channel of the trench gate isolation structure 5 cannot be opened under the action of positive voltage, so it only plays the role of isolating 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 negative voltage, and the channel of the trench gate isolation structure 5 is opened under the action of negative voltage. At this time, the fourth doped region 7 and the emitter region 301 are connected.

[0039] As an example, in another example, the trench gate isolation structure 5 can also be integrated into the driving control circuit as an electrode alone, and the selection is made according to actual needs.

[0040] As described above, in the reverse conducting IGCT device of the present embodiment, the GCT region and the FRD region are isolated by a trench gate isolation structure to improve the switching efficiency; and an N-type third doping region is arranged in the P-type emitter region, a P-type fourth doping region with a doping concentration greater than that of the emitter region is arranged in the N-type third doping region, and a P-type fifth doping region with a doping concentration greater than that of the fourth doping region is arranged in the fourth doping region. When the gate commutated thyristor is turned on, the trench gate isolation structure controls the channel to be turned 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 a low hole extraction speed is maintained to ensure that the reverse recovery process has better softness. When the gate commutated thyristor is turned off, the trench gate isolation structure controls the channel to be turned off. The isolation structure controls the opening of the channel, at which time the fourth doped region is connected to the emitter region, and under low current, the fourth doped region first participates in the conduction of the fast recovery diode, and as the current continues to increase, the fifth doped region also successively participates in the conduction, and the doping concentration of the emitter P of the fast recovery diode is increased to different degrees under different current levels, so that the injection efficiency of the emitter region is maintained at a large level under high current, and the emitter region has a smaller emission efficiency under low current, thereby improving the fast recovery diode's ability to resist surge current while taking into account the reverse recovery characteristics; in addition, fifth doped regions of different areas are set, and different numbers of fifth doped regions are turned on under different currents, thereby further improving the fast recovery diode's ability to resist surge current while taking into account the reverse recovery characteristics.

[0041] Embodiment 2

[0042] This embodiment provides a reverse-conducting IGCT device. Figure 2 The difference between the reverse conducting IGCT device of this embodiment and the reverse conducting IGCT device described in the first embodiment 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.

[0043] As an example, the auxiliary trench gate structure 16 is located in the emitter region 301, and 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, and the sidewalls and bottom of the auxiliary groove are provided with an auxiliary gate dielectric layer 1600, and the auxiliary groove is filled with an auxiliary gate conductive layer 1601; wherein, the material of the auxiliary gate dielectric layer 1600 is silicon oxide, and the material of the auxiliary gate conductive layer 1601 is polycrystalline silicon.

[0044] As an example, there are multiple auxiliary trench gate structures 16. In this embodiment, a part of the auxiliary trench gate structures 16 are located directly below the second metal layer 12, and a part of the auxiliary trench gate structures 16 are not located directly below the second metal layer 12. In another example, all of the multiple auxiliary trench gate structures 16 are located directly below the second metal layer 12, or all of the multiple auxiliary trench gate structures 16 are not located directly below the second metal layer 12, depending on the needs.

[0045] As an example, the ninth N-type doping region 17 is located in the emitter region 301 , and the ninth doping region 17 is in contact with a sidewall of the auxiliary trench gate structure 16 .

[0046] 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.

[0047] 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 .

[0048] As an example, the ninth doping region 17 contacting the sidewall 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.

[0049] 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 .

[0050] As an example, when the gate-commutated thyristor is turned on, the trench gate isolation structure 5 controls the channel of the third doping region 6 to be turned off, and the auxiliary trench gate structure 16 controls the trench of the ninth doping region 17 to be turned off.

[0051] As an example, when the gate-commutated thyristor is turned off, the trench gate isolation structure 5 controls the channel opening of the third doping region 6, and the auxiliary trench gate structure 16 controls the trench opening of the ninth doping region 17. Under small current, the fourth doping region 7 and the tenth doping region 18 first participate in the conduction of the fast recovery diode, and as the current continues to increase, the fifth doping region 8 and the eleventh doping region 19 also successively participate in conduction, thereby improving the device's surge resistance under large current and reverse recovery softness under small current.

[0052] 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 into the drive control circuit as an electrode alone, which is selected according to actual needs.

[0053] As an example, there are multiple eleventh doping regions 19, and the multiple eleventh doping regions 19 are arranged at intervals along the direction away from the auxiliary trench gate structure 16, wherein the areas (lateral widths) of the multiple eleventh doping regions 19 gradually decrease along the direction away from the auxiliary trench gate structure 16, or the areas (lateral widths) of the multiple eleventh doping regions 19 are the same, which is selected according to needs.

[0054] 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 from the second metal layer 12, wherein the insulating layer 20 is made of silicon oxide.

[0055] 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 to improve the switching efficiency; and an N-type third doping region is arranged in the P-type emitter region, a P-type fourth doping region with a doping concentration greater than that of the emitter region is arranged in the third doping region, and a P-type fifth doping region with a doping concentration greater than that of the fourth emitter region is arranged in the fourth doping region. When the gate commutation thyristor is turned on, the trench gate isolation structure controls the channel to be turned 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 a low hole extraction speed is maintained to ensure that the reverse recovery process has better softness. When the gate commutation thyristor is turned off, the trench gate isolation structure controls the channel to be turned off. The structure controls the opening of the channel. At this time, the fourth doping region is connected to the emitter region. Under low current, the fourth doping region first participates in the conduction of the fast recovery diode. As the current continues to increase, the fifth doping region also participates in the conduction successively. The doping concentration of the emitter of the fast recovery diode P is increased to different degrees under different current levels, so that the injection efficiency of the emitter region is kept large under high current, and the emitter region has a small emission efficiency under low current, thereby improving the ability of the fast recovery diode to resist surge current while taking into account the reverse recovery characteristics; in addition, multiple fifth doping regions of different areas are set, and different numbers of fifth doping regions are turned on under different currents, further improving the ability of the fast recovery diode to resist surge current while taking into account the reverse recovery characteristics. Therefore, the present invention effectively overcomes various shortcomings in the prior art and has a high industrial utilization value.

[0056] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall 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, wherein the doping concentration of the fourth doping region is greater than the doping concentration of the emission region; 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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