Reverse conducting IGBT for eliminating voltage foldback phenomenon

Abstract

The application discloses a reverse conducting IGBT for eliminating snapback phenomenon, comprising a half cell structure, the half cell structure comprising a collector structure, a voltage resistance layer structure, an emitter structure and a gate structure; the collector structure is located at one end of the voltage resistance layer structure, the emitter structure and the gate structure are located at two sides of the other end of the voltage resistance layer structure; wherein the collector structure comprises a P+ collector region, an N+ collector region, an N type buffer layer, a P+ conductive material, a collector metal, an N type conductive material and a floating metal; one side of the N type buffer layer is connected to the voltage resistance layer structure, one side of the P+ collector region and the N+ collector region is respectively connected to the other side of the N type buffer layer, and the P+ collector region and the N+ collector region have a gap therebetween, and the other side of the P+ collector region has the collector metal; the application eliminates the snapback phenomenon and makes the reverse conducting current more uniform by optimizing and improving the collector structure on the basis of the conventional reverse conducting IGBT structure.

Description

Technical Field

[0001] This invention relates to the field of power semiconductor technology, and more specifically to a reverse-conducting IGBT that eliminates voltage foldback. Background Technology

[0002] like Figures 3-4 The schematic diagram of the conventional reverse-conducting IGBT structure and equivalent circuit shown indicates that when the conventional reverse-conducting IGBT is forward-biased, the N+ collector region (12) conducts first. At this time, the device operates in unipolar conduction mode, and the on-resistance is relatively large. Due to the parasitic resistance of the N-type buffer layer (13), as the anode voltage increases, the anode current will generate a voltage drop across the parasitic resistance. When the potential difference between this voltage drop and the P+ collector region (11) is greater than 0.7V, the P+ collector region (13) / When the PN junction of the N-type buffer layer (13) is turned on, the device enters the bipolar conduction mode, and the conduction resistance is low. The sharp decrease in conduction resistance will cause voltage foldback. In order to alleviate this phenomenon, the length of the P+ collector region (11) of the conventional reverse-conducting IGBT is often designed to be very long. However, this will result in the N+ collector region (12) being relatively short. When the reverse-conducting IGBT device is reverse-conducting, the P+ body contact region (33), P-type well region (31), N-type drift region (21), N-type buffer layer (13) and N+ collector region (12) form diode conduction current. If the length of the N+ collector region (12) is short at this time, it will cause uneven distribution of reverse conduction current, which will affect the device performance and system reliability. Summary of the Invention

[0003] In order to solve the problems mentioned in the technical background, the present invention provides a reverse-conducting IGBT that eliminates the voltage foldback phenomenon. The voltage foldback phenomenon is eliminated by the introduction of the PN diode on the collector side, so the length ratio of the P+ collector region (11) to the N+ collector region (12) can be smaller, thereby making the current more uniform when the device is reverse-conducting.

[0004] This invention is achieved through the following technical solution:

[0005] A reverse-conducting IGBT that eliminates voltage foldback phenomenon is provided, comprising a half-cell structure, wherein the half-cell structure includes a collector structure, a withstand layer structure, an emitter structure, and a gate structure; the collector structure is located at one end of the withstand layer structure, and the emitter structure and the gate structure are located on both sides of the other end of the withstand layer structure.

[0006] The collector structure includes a P+ collector region, an N+ collector region and an N-type buffer layer, a P-type conductive material, a collector metal, an N-type conductive material and a floating metal;

[0007] One side of the N-type buffer layer is connected to the voltage-resisting layer structure, one side of the P+ collector region and the N+ collector region is respectively connected to the other side of the N-type buffer layer, and there is a gap between the P+ collector region and the N+ collector region, the other side of the P+ collector region has a collector metal which leads out a collector, and a floating metal is connected to the other side of the N+ collector region, and the collector metal is not in contact with the floating metal;

[0008] The P-type conductive material is arranged in the gap and connected to the floating metal, and the side of the P-type conductive material is spaced apart from the P+ collector region, the N+ collector region and the N-type buffer layer.

[0009] The N-type conductive material is connected to the P-type conductive material and one side of the N-type conductive material is connected to the collector metal.

[0010] Specifically, the emitter structure comprises a P-type well region, an N+ emitter region, a P+ body contact region and an emitter metal.

[0011] One side of the P-type well region is connected to the voltage-resisting layer structure, the N+ emitter region and the P+ body contact region are in contact with each other, and one side of the N+ emitter region and the P+ body contact region is connected to the other side of the P-type well region.

[0012] One side of the emitter metal leads out an emitter, and the other side of the emitter metal is connected to the N+ emitter region and the P+ body contact region.

[0013] Specifically, the gate structure comprises a trench gate, the trench gate is composed of a second insulating medium layer, a conductive material layer and a gate metal, the conductive material layer is arranged in the second insulating medium layer, and the gate metal is arranged on the conductive material layer and leads out a gate.

[0014] Specifically, one side of the second insulating medium layer vertically penetrates the P-type well region and is in contact with the P-type well region and the N+ emitter region.

[0015] Specifically, the voltage-resisting layer structure comprises an N-type drift region, and the N-type drift region is in contact with the second insulating medium layer and the P-type well region.

[0016] Preferably, an insulating medium layer is arranged in the gap between the P+ collector region and the N+ collector region, and the P-type conductive material is connected to the insulating medium layer.

[0017] Preferably, one side of the insulating medium layer is extended and attached to the N-type buffer layer.

[0018] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0019] Based on the conventional reverse-conducting IGBT structure, this invention eliminates the snapback phenomenon and makes the reverse conduction current more uniform by optimizing and improving the collector structure. Attached Figure Description

[0020] The accompanying drawings, which are included to provide a further understanding of the embodiments of the present invention and form part of this application, are not intended to limit the embodiments of the present invention.

[0021] Figure 1 This is a schematic diagram of the reverse-conducting IGBT structure of the present invention;

[0022] Figure 2 This is a schematic diagram of the equivalent circuit of the reverse-conducting IGBT of the present invention;

[0023] Figure 3 This is a schematic diagram of a conventional reverse-conducting IGBT structure;

[0024] Figure 4 This is a schematic diagram of the equivalent circuit of a conventional reverse-conducting IGBT.

[0025] Explanation of reference numerals in the attached figures:

[0026] 11. P+ collector region, 12. N+ collector region, 13. N-type buffer layer, 14. First insulating dielectric layer, 15. P-type conductive material, 16. Collector metal, 17. N-type conductive material, 18. Floating metal, 21. N-type drift region, 31. P-type well region, 32. N+ emitter region, 33. P+ body contact region, 34. Emitter metal, 41. Second insulating dielectric layer, 42. Conductive material layer, 43. Gate metal, C. Collector, E. Emitter, G. Gate. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0028] Example 1:

[0029] like Figures 1-2 The reverse-conducting IGBT shown here eliminates voltage foldback and includes a half-cell structure. The half-cell structure includes a collector structure, a voltage withstand layer structure, an emitter structure, and a gate structure. The collector structure is located at one end of the voltage withstand layer structure, and the emitter structure and the gate structure are located on both sides of the other end of the voltage withstand layer structure. The above content is prior art and will not be described in detail here.

[0030] The collector structure comprises a P+ collector region 11, an N+ collector region 12, an N-type buffer layer 13, a P-type conductive material 15, a collector metal 16, an N-type conductive material 17 and a floating metal 18;

[0031] One side of the N-type buffer layer 13 is connected to the voltage-resistant layer structure, one side of the P+ collector region 11 and the N+ collector region 12 are respectively connected to the other side of the N-type buffer layer 13, and there is a gap between the P+ collector region 11 and the N+ collector region 12, the other side of the P+ collector region 11 has the collector metal 16, the collector metal 16 leads out a collector C, the floating metal 18 is connected to the other side of the N+ collector region 12, and the collector metal 16 is not in contact with the floating metal 18;

[0032] The P-type conductive material 15 is disposed in the gap and connected to the floating metal 18, and the side edges of the P-type conductive material 15 are spaced apart from the P+ collector region 11, the N+ collector region 12 and the N-type buffer layer 13;

[0033] The N-type conductive material 17 is connected to the P-type conductive material 15 and one side of the N-type conductive material 17 is connected to the collector metal 16;

[0034] Specifically, the emitter structure comprises a P-type well region 31, an N+ emitter region 32, a P+ body contact region 33 and an emitter metal 34;

[0035] One side of the P-type well region 31 is connected to the voltage-resistant layer structure, the N+ emitter region 32 and the P+ body contact region 33 are in contact with each other, and one side of the N+ emitter region 32 and the P+ body contact region 33 are connected to the other side of the P-type well region 31;

[0036] One side of the emitter metal 34 leads out an emitter E, and the other side of the emitter metal 34 is connected to the N+ emitter region 32 and the P+ body contact region 33 at the same time;

[0037] The gate structure comprises a trench gate, the trench gate is composed of a second insulating medium layer 41, a conductive material layer 42 and a gate metal 43, the conductive material layer 42 is disposed in the second insulating medium layer 41, the gate metal 43 is disposed on the conductive material layer 42 and leads out a gate G, and one side of the second insulating medium layer 41 vertically penetrates the P-type well region 31 and is in contact with the P-type well region 31 and the N+ emitter region 32;

[0038] The voltage-resistant layer structure comprises an N-type drift region 21; the N-type drift region 21 is in contact with the first insulating medium 41 and the P-type well region 31;

[0039] The collector metal 16, the floating metal 18, the P-type conductive material 15 and the N-type conductive material 17 constitute a P-N diode in the present application. When the device is forward conducting, the P-N diode is reverse biased, and when the device is reverse conducting, the P-N diode is forward biased, thereby eliminating the voltage foldback phenomenon. Therefore, the length ratio of the P+ collector region 11 to the N+ collector region 12 can be smaller, and the current is more uniform when the device is reverse conducting. The specific working principle is as follows:

[0040] When forward conducting, the gate G is connected to a positive voltage, the collector C is connected to a positive voltage, and the emitter E is connected to ground. The voltage on the gate G opens the channel, and the electrons are injected into the N-type drift region 21. Since there is a reverse-biased P-N diode between the N+ collector region 12 and the collector C, the N+ collector region 12 does not conduct when the device is forward conducting, and only the P+ collector region 11 conducts. Therefore, when forward conducting, the device directly enters the bipolar conducting mode, and there is no voltage foldback phenomenon caused by the sudden change of the drift region resistance from unipolar conduction to bipolar conduction.

[0041] When reverse conducting, the gate G is connected to ground, the emitter E is connected to ground, and the collector C is connected to a negative voltage. The diode formed by the P+ body contact region 33, the P-type well region 31, the N-type drift region 21, the N-type buffer layer 13 and the N+ collector region 12 is connected in series with the P-N diode, and the device can achieve reverse conducting current function.

[0042] Embodiment 2:

[0043] Further, a first insulating medium layer 14 is arranged in the gap between the P+ collector region 11 and the N+ collector region 12, and the P-type conductive material 15 is connected to the first insulating medium layer 14.

[0044] Preferably, one side of the first insulating medium layer 14 is extended and attached to the N-type buffer layer 13.

[0045] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application, and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A reverse-conducting IGBT that eliminates voltage foldback, comprising a semi-cell structure, the semi-cell structure including a collector structure, a withstand layer structure, an emitter structure, and a gate structure; the collector structure is located at one end of the withstand layer structure, and the emitter structure and gate structure are located on opposite sides of the other end of the withstand layer structure, characterized in that, The collector structure comprises a P+ collector region (11), an N+ collector region (12), an N-type buffer layer (13), a P-type conductive material (15), a collector metal (16), an N-type conductive material (17) and a floating metal (18). One side of the N-type buffer layer (13) is connected to the voltage-resistant layer structure, one side of the P+ collector region (11) and the N+ collector region (12) is respectively connected to the other side of the N-type buffer layer (13), and there is a gap between the P+ collector region (11) and the N+ collector region (12), the other side of the P+ collector region (11) has the collector metal (16), the collector metal (16) leads out a collector (C), the floating metal (18) is connected to the other side of the N+ collector region (12), and the collector metal (16) is not in contact with the floating metal (18). The P-type conductive material (15) is arranged in the gap and connected to the floating metal (18), and the side of the P-type conductive material (15) is spaced apart from the P+ collector region (11), the N+ collector region (12) and the N-type buffer layer (13). The N-type conductive material (17) is connected to the P-type conductive material (15) and one side of the N-type conductive material (17) is connected to the collector metal (16), a first insulating medium layer (14) is arranged in the gap between the P+ collector region (11) and the N+ collector region (12), and the P-type conductive material (15) is connected to the first insulating medium layer (14).

2. The reverse conducting IGBT for eliminating a voltage foldback phenomenon according to claim 1, wherein One side of the first insulating medium layer (14) is extended and attached to the N-type buffer layer (13).

3. The reverse conducting IGBT for eliminating a voltage foldback phenomenon according to claim 2, characterized by, The emitter structure comprises a P-type well region (31), an N+ emitter region (32), a P+ body contact region (33) and an emitter metal (34). One side of the P-type well region (31) is connected to the voltage-resistant layer structure, the N+ emitter region (32) and the P+ body contact region (33) are in contact with each other, and one side of the N+ emitter region (32) and the P+ body contact region (33) is connected to the other side of the P-type well region (31). One side of the emitter metal (34) leads out an emitter (E), and the other side of the emitter metal (34) is connected to the N+ emitter region (32) and the P+ body contact region (33) at the same time.

4. The reverse conducting IGBT for eliminating a voltage foldback phenomenon according to claim 3, characterized by, The gate structure comprises a trench gate, the trench gate is composed of a second insulating medium layer (41), a conductive material layer (42) and a gate metal (43), the conductive material layer (42) is arranged in the second insulating medium layer (41), and the gate metal (43) is arranged on the conductive material layer (42) and leads out a gate (G).

5. The reverse conducting IGBT for eliminating a voltage collapse phenomenon according to claim 4, wherein One side of the second insulating medium layer (41) vertically penetrates the P-type well region (31) and is in contact with the P-type well region (31) and the N+ emitter region (32).

6. The reverse conducting IGBT for eliminating a voltage collapse phenomenon according to claim 5, wherein The voltage-resistant layer structure comprises an N-type drift region (21), the N-type drift region (21) is in contact with the second insulating medium layer (41) and the P-type well region (31).

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