Large-current trench gate field cut-off IGBT power device

Abstract

The utility model provides a large-current trench gate field cut-off IGBT power device. The large-current trench gate field cut-off IGBT power device comprises a heavily doped first conductive type substrate; a heavily doped second conductive type collector region is arranged on the back surface of the first conductive type substrate, and collector metal is arranged on the back surface of the second conductive type collector region; a first conductive type buffer layer is arranged on the front surface of the first conductive type substrate; a lightly doped first conductive type epitaxial layer is arranged on the first conductive type buffer layer; a gate trench, a lightly doped second conductive type body region and a voltage dividing ring are arranged at the top in the first conductive type epitaxial layer; wherein the gate trench and the second conductive type body region are located in an active region of the device, and the voltage dividing ring is located in a terminal protection region of the device; the plurality of gate trenches are arranged in parallel, and two sides of the plurality of parallel gate trenches are respectively provided with a second conductive type body region; the number of the voltage dividing rings is at least one. The device has the advantages of high reverse breakdown voltage, high forward current capability and the like.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductors, in particular to a high-current trench gate field cutoff IGBT power device. Background Art

[0002] IGBT power device is a kind of device with the advantages of high input impedance, low on-state voltage drop, high voltage resistance, high current carrying capacity, fast switching speed, etc.; it is widely used in industrial control, rail transportation, power system control, electric vehicles, energy-saving home appliances and other fields.

[0003] For IGBT power devices used in energy-saving home appliances such as variable-frequency air conditioners, microwave ovens, and washing machines, they are required to have a reverse withstand voltage of >650V, a current capacity of 40A, a gate drive voltage of <2V, and stable withstand voltage and high current carrying capacity. Summary of the invention

[0004] The purpose of the embodiment of the utility model is to provide a high current trench gate field stop IGBT power device, which has the advantages of high reverse breakdown voltage, large forward current capability, low driving voltage, etc., and can meet the requirements of energy-saving home appliances such as air conditioner inverters and microwave ovens. In order to achieve the above technical objectives, the technical solution adopted by the embodiment of the utility model is:

[0005] The present invention provides a high current trench gate field stop IGBT power device, comprising:

[0006] A heavily doped first conductive type substrate; a heavily doped second conductive type collector region is provided on the back of the first conductive type substrate, and a collector metal is provided on the back of the second conductive type collector region;

[0007] A first conductive type buffer layer is provided on the front side of the first conductive type substrate; a lightly doped first conductive type epitaxial layer is provided on the first conductive type buffer layer; a gate trench, a lightly doped second conductive type body region and a voltage divider ring are provided on the top of the first conductive type epitaxial layer; wherein the gate trench and the second conductive type body region are located in the active region of the device, and the voltage divider ring is located in the terminal protection region of the device; a plurality of gate trenches are arranged in parallel, and a second conductive type body region is provided on both sides of the plurality of parallel gate trenches respectively; and the number of the voltage divider ring is at least one;

[0008] The inner wall of the gate trench is provided with a gate oxide layer, and the gate trench is filled with gate polysilicon;

[0009] A heavily doped second conductivity type emitter region and a heavily doped first conductivity type gate region are arranged in parallel on the top of the second conductivity type body region; the second conductivity type emitter region is located outside the first conductivity type gate region;

[0010] A first insulating layer is provided on the surface of the first conductive type epitaxial layer, a thick oxide layer is provided on the first insulating layer; a doped polysilicon layer and an interlayer insulating layer are provided in sequence above the thick oxide layer; an emitter metal is provided on the interlayer insulating layer;

[0011] In the active area, openings are provided in the thick oxide layer, the doped polysilicon layer and the interlayer insulating layer above the plurality of parallel gate trenches, and gate metal is provided in the openings;

[0012] The gate metal is electrically connected to the gate polysilicon in the gate trench and the first conductive type gate region in the second conductive type body region through the gate contact hole; the emitter metal is electrically connected to the second conductive type emitter region in the second conductive type body region through the emitter contact hole.

[0013] Furthermore, the thickness of the thick oxide layer is 1.8 μm to 2 μm.

[0014] Furthermore, the gate trench has a depth of 4 μm to 5 μm and a width of 0.8 μm to 1.5 μm.

[0015] Furthermore, the doping concentration of the first conductive type substrate is 1e20 / cm³ to 1e21 / cm³.

[0016] Furthermore, the thickness of the interlayer insulating layer is 0.8 μm to 1.2 μm.

[0017] Furthermore, the material of the interlayer insulating layer is USG or PSG.

[0018] Furthermore, the number of the voltage divider rings is 3 to 4.

[0019] The beneficial effects brought by the technical solution provided by the embodiment of the utility model are:

[0020] 1) The reverse breakdown voltage of the device is high, which improves the device's withstand voltage.

[0021] 2) The gate structure adopts trench gate, which can reduce the on-state voltage drop by about 30% compared with the planar gate; the current density is large; and the forward current capability of the device is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the structure of an IGBT power device in an embodiment of the utility model. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0024] In this embodiment, the first conductivity type is N type, and the second conductivity type is P type;

[0025] like Figure 1 As shown, a high current trench gate field stop IGBT power device proposed in an embodiment of the utility model comprises:

[0026] A heavily doped first conductive type substrate 1; a heavily doped second conductive type collector region 2 is provided on the back of the first conductive type substrate 1, and a collector metal 3 is provided on the back of the second conductive type collector region 2;

[0027] A first conductive type buffer layer 4 is provided on the front side of the first conductive type substrate 1; a lightly doped first conductive type epitaxial layer 5 is provided on the first conductive type buffer layer 4; a gate trench 6, a lightly doped second conductive type body region 7 and a voltage divider ring 8 are provided on the top of the first conductive type epitaxial layer 5; wherein the gate trench 6 and the second conductive type body region 7 are located in the active area of ​​the device, and the voltage divider ring 8 is located in the terminal protection area of ​​the device; a plurality of gate trenches 6 are arranged in parallel, and a second conductive type body region 7 is provided on both sides of the plurality of parallel gate trenches 6 respectively; and the number of the voltage divider ring 8 is at least one;

[0028] The inner wall of the gate trench 6 is provided with a gate oxide layer 61, and the gate trench 6 is filled with gate polysilicon 62;

[0029] A heavily doped second conductivity type emitter region 91 and a heavily doped first conductivity type gate region 92 are arranged in parallel on the top of the second conductivity type body region 7; the second conductivity type emitter region 91 is located outside the first conductivity type gate region 92;

[0030] A first insulating layer 10 is provided on the surface of the first conductive type epitaxial layer 5, and a thick oxide layer 11 is provided on the first insulating layer 10; a doped polysilicon layer 12 and an interlayer insulating layer 13 are provided in sequence above the thick oxide layer 11; and an emitter metal 14 is provided on the interlayer insulating layer 13;

[0031] In the active area, openings are provided in the thick oxide layer 11, the doped polysilicon layer 12 and the interlayer insulating layer 13 above the plurality of parallel gate trenches 6, and gate metal 15 is provided in the openings;

[0032] The gate metal 15 is electrically connected to the gate polysilicon 62 in the gate trench 6 and the first conductive type gate region 92 in the second conductive type body region 7 through the gate contact hole; the emitter metal 14 is electrically connected to the second conductive type emitter region 91 in the second conductive type body region 7 through the emitter contact hole.

[0033] Furthermore, the thickness of the thick oxide layer 11 is 1.8 μm to 2 μm, which can significantly improve the reverse withstand voltage capability of the device; the material of the thick oxide layer 11 can be SiO2. The doped polysilicon layer 12 above the thick oxide layer 11 can also improve the withstand voltage of the device.

[0034] Furthermore, the gate trench 6 has a depth of 4 μm to 5 μm and a width of 0.8 μm to 1.5 μm. The deeper gate trench 6 can significantly improve the forward current capability of the device.

[0035] Specifically, the doping concentration of the first conductive type substrate 1 is 1e20 / cm³ to 1e21 / cm³, which can further reduce the on-resistance.

[0036] Specifically, the thickness of the interlayer insulating layer 13 is 0.8 μm to 1.2 μm; the material of the interlayer insulating layer 13 is USG or PSG.

[0037] Furthermore, the number of the voltage divider rings 8 is 3 to 4, which can further improve the voltage resistance of the device.

[0038] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model is described in detail with reference to the embodiments, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. A high current trench gate field stop IGBT power device, characterized in that: include: A heavily doped first conductive type substrate (1); a heavily doped second conductive type collector region (2) is provided on the back side of the first conductive type substrate (1); and a collector metal (3) is provided on the back side of the second conductive type collector region (2); A first conductive type buffer layer (4) is provided on the front side of a first conductive type substrate (1); a lightly doped first conductive type epitaxial layer (5) is provided on the first conductive type buffer layer (4); a gate trench (6), a lightly doped second conductive type body region (7) and a voltage divider ring (8) are provided on the top of the first conductive type epitaxial layer (5); wherein the gate trench (6) and the second conductive type body region (7) are located in the active region of the device, and the voltage divider ring (8) is located in the terminal protection region of the device; a plurality of gate trenches (6) are arranged in parallel, and a second conductive type body region (7) is provided on both sides of the plurality of parallel gate trenches (6); and the number of the voltage divider ring (8) is at least one; The inner wall of the gate trench (6) is provided with a gate oxide layer (61), and the gate trench (6) is filled with gate polysilicon (62); A heavily doped second conductive type emitter region (91) and a heavily doped first conductive type gate region (92) are arranged in parallel on the top of the second conductive type body region (7); the second conductive type emitter region (91) is located outside the first conductive type gate region (92); A first insulating layer (10) is provided on the surface of the first conductive type epitaxial layer (5); a thick oxide layer (11) is provided on the first insulating layer (10); a doped polysilicon layer (12) and an interlayer insulating layer (13) are provided in sequence above the thick oxide layer (11); and an emitter metal (14) is provided on the interlayer insulating layer (13); In the active area, openings are provided in the thick oxide layer (11), the doped polysilicon layer (12) and the interlayer insulating layer (13) above the plurality of parallel gate trenches (6), and gate metal (15) is provided in the openings; The gate metal (15) is electrically connected to the gate polysilicon (62) in the gate trench (6) and the first conductive type gate region (92) in the second conductive type body region (7) through the gate contact hole; and the emitter metal (14) is electrically connected to the second conductive type emitter region (91) in the second conductive type body region (7) through the emitter contact hole.

2. The high current trench gate field stop IGBT power device according to claim 1, characterized in that: The thickness of the thick oxide layer (11) is 1.8 μm to 2 μm.

3. The high current trench gate field stop IGBT power device according to claim 1, characterized in that: The gate trench (6) has a depth of 4 μm to 5 μm and a width of 0.8 μm to 1.5 μm.

4. The high current trench gate field stop IGBT power device according to claim 1, characterized in that: The thickness of the interlayer insulating layer (13) is 0.8 μm to 1.2 μm.

5. The high current trench gate field stop IGBT power device according to claim 1, characterized in that: The material of the interlayer insulating layer (13) is USG or PSG.

6. The high current trench gate field stop IGBT power device according to claim 1, characterized in that: The number of the pressure dividing rings (8) is 3 to 4.

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