Trench IGBT Device with Multiple Regulations

Abstract

The present invention relates to a trench-type IGBT device with multiple regulations. It includes a semiconductor substrate and a cell region; for any cell, it includes a first cell trench and a second cell trench. Among them, a multiple regulation region is arranged between the first cell trench and the second cell trench. The multiple regulation region contacts the corresponding outer walls of the first cell trench and the second cell trench, and the multiple regulation region is adaptively connected to the emitter metal for forming the emitter of the IGBT device; when the trench-type IGBT device is in the forward conduction state, the multiple regulation region stores hole carriers to regulate the distribution of hole carriers, and uses the distribution of the regulated hole carriers to reduce the conduction voltage drop; when the trench-type IGBT device is in the reverse off state, the multiple regulation region extracts hole carriers. The present invention can achieve multiple regulations on the accumulation and extraction of hole carriers, and further achieve an optimization of the compromise between the conduction voltage drop and the turn-on loss.

Description

Technical Field

[0001] The present invention relates to a trench IGBT device, in particular to a trench IGBT device with multiple regulations. Background Art

[0002] IGBT devices are a representative type of power semiconductor devices. Due to their advantages such as high breakdown voltage, low on-state voltage drop, easy driving, and fast switching speed, they have important applications in many power fields such as switched-mode power supplies, variable frequency drives, and inverters.

[0003] Since the invention of IGBT devices, reducing the power loss of IGBT devices, that is, optimizing the trade-off between on-state loss and off-state loss, has always been one of the directions of IGBT device technology development. One of the main ideas is to optimize the carrier distribution inside the device during conduction to reduce the turn-on loss. For example, in trench gate charge storage IGBT devices, an N-type charge storage layer is introduced under the P-type body region to form a hole barrier, which enhances the surface carrier concentration, reduces the on-state voltage drop of the device, and optimizes the trade-off between on-state voltage drop and off-state loss. Another example is to set a Floating P region on the device surface to achieve the storage of hole carriers, enhance the conductivity modulation, and reduce the on-state voltage drop.

[0004] Currently, for traditional trench gate charge storage IGBT devices, the on-state voltage drop is generally optimized by the concentration and depth of the N-type charge storage layer. However, as the concentration and depth of the N-type charge storage layer increase, the better the conductivity modulation effect, the lower the on-state voltage drop of the device, but it will also be accompanied by an increase in off-state loss, a decrease in breakdown voltage, and an increase in short-circuit current. Therefore, the regulation effect is still relatively limited.

[0005] In addition, the setting of the Floating P region is another commonly used means to enhance the positive carrier storage effect, but the displacement current of the Floating P region will cause the negative gate capacitance effect, which in turn causes the EMI problem of gate oscillation. Summary of the Invention

[0006] The object of the present invention is to overcome the deficiencies in the prior art and provide a trench IGBT device with multiple regulations, which can achieve multiple regulations on the accumulation and extraction of hole carriers, and further realize the optimization of the trade-off between on-state voltage drop and turn-on loss.

[0007] According to the technical solution provided by the present invention, the trench IGBT device with multiple regulations includes a semiconductor substrate of a first conductivity type and a cell region prepared in the central region of the semiconductor substrate. The cell region includes a plurality of cells distributed in parallel, and the cells in the cell region adopt a trench structure;

[0008] For any cell, including a first trench of the cell and a second trench of the cell adjacent to the first trench of the cell, where

[0009] A multiple regulation region for hole carrier storage or hole carrier extraction is provided between the first trench of the cell and the second trench of the cell. The multiple regulation region is distributed along the corresponding length directions of the first trench of the cell and the second trench of the cell. The multiple regulation region is in contact with the corresponding outer walls of the first trench of the cell and the second trench of the cell, and the multiple regulation region is adaptively connected to the emitter metal for forming the emitter of the IGBT device;

[0010] When the trench-type IGBT device is in the forward conduction state, the multiple regulation region stores hole carriers to regulate the distribution of hole carriers, and reduces the conduction voltage drop by using the distribution of the regulated hole carriers;

[0011] When the trench-type IGBT device is in the reverse off state, the multiple regulation region extracts hole carriers.

[0012] The multiple regulation region includes a carrier storage layer of a first conduction type, a base region of a second conduction type prepared on the carrier storage layer of the first conduction type, and a plurality of multiple regulation units prepared on the base region of the second conduction type, where

[0013] The carrier storage layer of the first conduction type and the base region of the second conduction type are both distributed along the corresponding length directions of the first trench of the cell and the second trench of the cell. The carrier storage layer of the first conduction type is located above the corresponding bottom of the first trench of the cell and the second trench of the cell;

[0014] For any multiple regulation unit, it includes a source region of a first conduction type, a first doping region of a second conduction type, a body region of a second conduction type, and a second doping region of a second conduction type that are sequentially distributed along the length direction of the first trench of the cell;

[0015] When there are multiple multiple regulation units on the base region of the second conduction type, the multiple multiple regulation units are periodically arranged on the base region of the second conduction type along the corresponding length directions of the first trench of the cell and the second trench of the cell; for two adjacent multiple regulation regions, the second doping region of a second conduction type of one multiple regulation region is in contact with the source region of a first conduction type of the other multiple regulation region;

[0016] The source region of the first conduction type and the base region of the second conduction type form an upper hole barrier region. The emitter metal and the body region of the second conduction type form a non-ohmic contact with a hole barrier. The emitter metal is in ohmic contact with the source region of the first conduction type, the first doping region of the second conduction type, and the second doping region of the second conduction type.

[0017] The doping concentration of the first doping region of the second conduction type is consistent with the doping concentration of the second doping region of the second conduction type;

[0018] The doping concentration of the second-conductivity-type body region is consistent with that of the second-conductivity-type base region, and the doping concentration of the second-conductivity-type body region is less than that of the first doping region of the second-conductivity-type;

[0019] Within the multiple regulation unit, the first-conductivity-type source region, the first doping region of the second-conductivity-type, the second-conductivity-type body region, and the second doping region of the second-conductivity-type all vertically extend from the corresponding notches of the first cell trench and the second cell trench to the second-conductivity-type base region.

[0020] An emitter contact hole is provided between the first cell trench and the second cell trench, and emitter metal is filled in the emitter contact hole so that the emitter metal is in adaptive contact with the multiple regulation unit, where

[0021] the depths of the emitter contact hole in the first-conductivity-type source region, the first doping region of the second-conductivity-type, the second-conductivity-type body region, and the second doping region of the second-conductivity-type are consistent,

[0022] and the depth of the emitter contact hole is less than the corresponding thicknesses of the first-conductivity-type source region, the first doping region of the second-conductivity-type, the second-conductivity-type body region, and the second doping region of the second-conductivity-type.

[0023] The emitter contact hole penetrates the first-conductivity-type source region, the first doping region of the second-conductivity-type, the second-conductivity-type body region, and the second doping region of the second-conductivity-type, or

[0024] the corresponding emitter contact holes in the first-conductivity-type source region, the first doping region of the second-conductivity-type, the second-conductivity-type body region, and the second doping region of the second-conductivity-type are not completely connected.

[0025] The widths of the emitter contact hole in the first-conductivity-type source region, the first doping region of the second-conductivity-type, the second-conductivity-type body region, and the second doping region of the second-conductivity-type are consistent, or

[0026] the widths of the emitter contact hole in the first doping region of the second-conductivity-type and the second doping region of the second-conductivity-type are greater than the widths of the emitter contact hole in the first-conductivity-type source region and the second-conductivity-type body region.

[0027] The junction depth of the first doping region of the second-conductivity-type is not less than the junction depth of the first-conductivity-type source region.

[0028] A trench gate structure is provided in both the first cell trench and the second cell trench, where

[0029] The trench gate structure includes gate conductive polysilicon. The gate conductive polysilicon filled in the first trench of the cell is insulated from the inner wall of the first trench of the cell by an insulating gate oxide layer covering the inner wall of the first trench of the cell. The gate conductive polysilicon filled in the second trench of the cell is insulated from the inner wall of the second trench of the cell by an insulating gate oxide layer covering the inner wall of the second trench of the cell.

[0030] A back electrode structure adapted to the IGBT device is provided on the back surface of the semiconductor substrate.

[0031] Both the first trench of the cell and the second trench of the cell are strip-shaped, and the length direction of the first trench of the cell is consistent with the length direction of the second trench of the cell.

[0032] Among the "first conduction type" and "second conduction type", for an N-type GBT device, the first conduction type refers to N-type and the second conduction type is P-type; for a P-type IGBT device, the types referred to by the first conduction type and the second conduction type are exactly opposite to those of an N-type semiconductor device.

[0033] Advantages of the present invention: The first conduction type source region and the second conduction type base region form an upper hole barrier region. The emitter metal and the second conduction type body region form a non-Ohmic contact with a hole barrier. The emitter metal has an Ohmic contact with the second conduction type first doping region and the second conduction type second doping region. Therefore, during forward conduction, on the basis of using the first conduction type carrier storage layer, carrier storage can be further achieved, so as to achieve the purpose of regulating the carrier distribution and reducing the conduction voltage drop. During reverse turn-off, by using the second conduction type second doping region and the second conduction type second doping region, extraction of hole carriers can be realized, that is, multiple regulation of hole carrier storage and extraction can be realized, further optimizing the trade-off between the conduction voltage drop and the turn-off loss of the device. Description of the Drawings

[0034] Figure 1 It is a top plan view schematic diagram of a cell of the present invention.

[0035] Figure 2 It is Figure 1 the cross-sectional view taken along the line A-A in

[0036] Figure 3 It is Figure 1 the cross-sectional view taken along the line B-B in

[0037] Figure 4 It is Figure 1 the cross-sectional view taken along the line C-C in

[0038] Explanation of the reference numerals: 1-N-type substrate, 2-gate conductive polysilicon, 3-insulating gate oxide layer, 4-N-type carrier storage layer, 5-P-type body region, 6-N+ source region, 7-emitter contact hole, 8-N+ field stop layer, 9-P+ collector region, 10-P-type first doped region, 11-P-type second doped region, 12-unit cell first trench, 13-unit cell second trench, 14-P-type base region. DETAILED DESCRIPTION

[0039] The present invention will be further described below in conjunction with specific drawings and embodiments.

[0040] In order to achieve multiple controls on hole carrier accumulation and extraction, and further optimize the compromise between on-state voltage drop and turn-on loss, for a trench IGBT device with multiple controls, taking the first conductivity type as N type and the second conductivity type as P type as an example, in one embodiment of the present invention, it includes a semiconductor substrate with N conductivity type and a cell region prepared in the central area of the semiconductor substrate, the cell region includes a plurality of cells distributed in parallel, and the cells in the cell region adopt a trench structure;

[0041] For any cell, it includes a cell first groove 12 and a cell second groove 13 adjacent to the cell first groove 12, wherein:

[0042] A multiple control area for hole carrier storage or hole carrier extraction is provided between the first cell groove 12 and the second cell groove 13, and the multiple control areas are distributed along the corresponding length directions of the first cell groove 12 and the second cell groove 13, and the multiple control areas are in contact with the corresponding outer walls of the first cell groove 12 and the second cell groove 13, and the multiple control areas are adaptively connected with the emitter metal for forming the emitter of the IGBT device;

[0043] When the trench IGBT device is in a forward conduction state, multiple control areas are used to store hole carriers to control the distribution of hole carriers, and the controlled distribution of hole carriers is used to reduce the conduction voltage drop;

[0044] When the trench IGBT device is in a reverse off state, hole carriers are extracted using multiple control regions.

[0045] Generally, the material of the semiconductor substrate can be any commonly used material, such as silicon. Figures 2 to 4 , an embodiment of a semiconductor substrate including an N-type substrate 1 is shown. The cell region is generally located in the central region of the semiconductor substrate. Of course, a terminal structure is generally required to be provided in the outer circle of the cell region. The terminal structure can be used to protect the cell region. The specific positional relationship and function between the cell region and the terminal structure are consistent with the existing ones.

[0046] The cell region includes a number of cells, and the cells in the cell region are connected in parallel as a whole. In one embodiment of the present invention, the cells in the cell region adopt a trench structure. Figures 1 to 4 In it, for any cell, it includes a first cell trench 12 and a second cell trench 13. The first cell trench 12 and the second cell trench 13 extend vertically downward from the front surface of the N-type substrate 1. Generally, the first cell trench 12 and the second cell trench 13 have the same depth in the N-type substrate 1 and are less than the thickness of the N-type substrate 1.

[0047] Figure 1 In it, the first cell trench 12 and the second cell trench 13 are both strip-shaped, and the length direction of the first cell trench 12 is consistent with the length direction of the second cell trench 13. The first cell trench 12 and the second cell trench 13 are parallel to each other.

[0048] In order to achieve multiple regulations, a multiple regulation region is arranged between the first cell trench 12 and the second cell trench 13. Figure 1 In it, the multiple regulation region is distributed along the length directions of the first cell trench 12 and the second cell trench 13, contacts the outer walls of the first cell trench 12 and the second cell trench 13, and is adaptively connected to the emitter metal for forming the emitter electrode of the IGBT device.

[0049] For multiple regulations, specifically, when the IGBT device conducts forward, the multiple regulation region can be used to further store hole carriers, so as to regulate the distribution of hole carriers and achieve the purpose of reducing the conduction voltage drop. When the IGBT device is turned off reversely, the multiple regulation region is used to extract hole carriers to achieve the purpose of improving the turn-off speed, that is, the trade-off between the conduction voltage drop and the turn-off loss of the IGBT device can be optimized.

[0050] In one embodiment of the present invention, the multiple regulation region includes an N-type carrier storage layer 4, a P-type base region 14 prepared on the N-type carrier storage layer 4, and a number of multiple regulation units prepared on the P-type base region 14. Among them,

[0051] The N-type carrier storage layer 4 and the P-type base region 14 are both distributed along the corresponding length directions of the first cell trench 12 and the second cell trench 13. The N-type carrier storage layer 4 is located above the corresponding bottom of the first cell trench 12 and the second cell trench 13.

[0052] For any multiple regulation unit, it includes an N+ source region 6, a P-type first doping region 10, a P-type body region 5, and a P-type second doping region 11 that are distributed in sequence along the length direction of the first cell trench 12.

[0053] When there are multiple multiple regulation units on the P-type base region 14, the multiple multiple regulation units are arranged periodically along the corresponding length directions of the cell first trench 12 and the cell second trench 13 on the P-type base region 14; for two adjacent multiple regulation regions, the P-type second doping region 11 of one multiple regulation region is in contact with the N+ source region 6 of the other multiple regulation region.

[0054] The N+ source region 6 and the P-type base region 14 form an upper hole barrier region, the emitter metal forms a non-ohmic contact with a hole barrier with the P-type body region 5, and the emitter metal has an ohmic contact with the P-type first doping region 10 and the P-type second doping region 11.

[0055] Figures 1 to 4 An embodiment of the multiple regulation region is shown, that is, it includes an N-type carrier storage layer 4, a P-type base region 14 and a multiple regulation unit. The N-type carrier storage layer 4 is located below the P-type base region 14, and the N-type carrier storage layer 4 needs to be located above the corresponding bottom of the cell first trench 12 and the cell second trench 13. Both the N-type carrier storage layer 4 and the P-type base region 14 are distributed along the lengths of the cell first trench 12 and the cell second trench 13. The N-type carrier storage layer 4 and the P-type base region 14 are in contact with the corresponding outer walls of the cell first trench 12 and the cell second trench 13 in the N-type substrate 1. A P well is formed by using the P-type base region 14, and the storage of carriers is realized by using the N-type carrier storage layer 4. The specific functions of the N-type carrier storage layer 4 and the P-type base region 14 are the same as those in the prior art.

[0056] The P-type base region 14 is adjacent to the N-type carrier storage layer 4, and at least one multiple regulation unit is arranged on the P-type base region 14; when there are multiple multiple regulation units, the multiple multiple regulation units are arranged periodically, and the arrangement direction of the multiple regulation units is consistent with the length directions of the cell first trench 12 and the cell second trench 13.

[0057] From Figures 1 to 4 it can be seen that for any multiple regulation unit, it includes an N+ source region 6, a P-type first doping region 10, a P-type body region 5 and a P-type second doping region 11 arranged in sequence, that is, the N+ source region 6, the P-type first doping region 10, the P-type body region 5 and the P-type second doping region 11 are arranged in sequence on the P-type base region 14. When arranged periodically, the P-type second doping region 11 of one multiple regulation region is in contact with the N+ source region 6 of the other multiple regulation region.

[0058] For Figures 1 to 4 the multiple regulation unit shown, the emitter metal is adaptively connected to the multiple regulation unit. Specifically, it means that: the N+ source region 6 and the P-type base region 14 form an upper hole barrier region, the emitter metal forms a non-ohmic contact with a hole barrier with the P-type body region 5, and the emitter metal has an ohmic contact with the N+ source region 6, the P-type first doping region 10 and the P-type second doping region 11.

[0059] Furthermore, the doping concentration of the P-type first doping region 10 is consistent with that of the P-type second doping region 11;

[0060] The doping concentration of the P-type body region 5 is consistent with that of the P-type base region 14, and the doping concentration of the P-type body region 5 is less than that of the P-type first doping region 10;

[0061] Within the multiple regulation unit, the N+ source region 6, the P-type first doping region 10, the P-type body region 5, and the P-type second doping region 11 all vertically extend from the corresponding notches of the first cell trench 12 and the second cell trench 13 to the P-type base region 14.

[0062] In specific implementation, the P-type first doping region 10 and the P-type second doping region 11 have the same doping concentration, the doping concentration of the P-type body region 5 is consistent with that of the P-type base region 14, and the doping concentrations of the P-type body region 5 and the P-type body region 14 are less than those of the P-type first doping region 10 and the P-type second doping region 11.

[0063] Figures 1 to 4 Among them, the N+ source region 6, the P-type first doping region 10, the P-type body region 5, and the P-type second doping region 11 all vertically extend from the corresponding notches of the first cell trench 12 and the second cell trench 13 to the P-type base region 14. The lengths of the N+ source region 6, the P-type first doping region 10, the P-type body region 5, and the P-type second doping region 11 along the length direction of the first cell trench 12 can be selected according to actual needs.

[0064] In an embodiment of the present invention, an emitter contact hole 7 is provided between the first cell trench 12 and the second cell trench 13, and emitter metal is filled in the emitter contact hole 7 so that the emitter metal is adaptively contacted with the multiple regulation unit, wherein,

[0065] The depths of the emitter contact hole 7 in the N+ source region 6, the P-type first doping region 10, the P-type body region 5, and the P-type second doping region 11 are consistent,

[0066] The depth of the emitter contact hole 7 is less than the corresponding thicknesses of the N+ source region 6, the P-type first doping region 10, the P-type body region 5, and the P-type second doping region 11.

[0067] In order to satisfy the adaptive connection of the emitter metal, an emitter contact hole 7 is provided between the first cell trench 12 and the second cell trench 13, that is, the emitter metal is adaptively contacted with the multiple regulation unit by using the emitter contact hole. Figures 1 to 4 Among them, the emitter metal is not shown, and the form of forming the emitter of the IGBT device by using the emitter metal is consistent with the existing one, specifically based on the ability to form an emitter by using the emitter metal.

[0068] In specific implementation, the depth of the emitter contact hole 7 is the same in the N+ source region 6, the P-type first doped region 10, the P-type body region 5, and the P-type second doped region 11. Figures 2 to 4 In Figures 2 to 4 , the depth of the emitter contact hole 7 is less than the corresponding thicknesses of the N+ source region 6, the P-type first doped region 10, the P-type body region 5, and the P-type second doped region 11.

[0069] In addition, the emitter contact hole 7 penetrates through the N+ source region 6, the P-type first doped region 10, the P-type body region 5, and the P-type second doped region 11, or

[0070] the corresponding emitter contact holes 7 in the N+ source region 6, the P-type first doped region 10, the P-type body region 5, and the P-type second doped region 11 are not completely connected.

[0071] Figure 1 In , an embodiment is shown where the emitter contact hole 7 penetrates through the N+ source region 6, the P-type first doped region 10, the P-type body region 5, and the P-type second doped region 11. In a specific process, the corresponding emitter contact holes 7 in the N+ source region 6, the P-type first doped region 10, the P-type body region 5, and the P-type second doped region 11 may not be completely connected, specifically as long as the emitter metal can use the emitter contact hole to satisfy the corresponding contact connection with the N+ source region 6, the P-type first doped region 10, the P-type body region 5, and the P-type second doped region 11.

[0072] In an embodiment of the present invention, the corresponding widths of the emitter contact hole 7 in the N+ source region 6, the P-type first doped region 10, the P-type body region 5, and the P-type second doped region 11 are the same, or

[0073] the corresponding widths of the emitter contact hole 7 in the P-type first doped region 10 and the P-type second doped region 11 are greater than the corresponding widths of the emitter contact hole 7 in the N+ source region 6 and the P-type body region 5.

[0074] Figure 1 In Figure 1 , a case where the emitter contact hole 7 has the same width is shown, where the width of the emitter contact hole 7 is less than the corresponding widths of the N+ source region 6, the P-type first doped region 10, the P-type body region 5, and the P-type second doped region 11.

[0075] When the emitter contact hole 7 has different widths, it is preferably that the corresponding widths of the emitter contact hole 7 in the P-type first doped region 10 and the P-type second doped region 11 are greater than the corresponding widths of the emitter contact hole 7 in the N+ source region 6 and the P-type body region 5. The width situation of the emitter contact hole 7 can be determined according to actual processes, etc.

[0076] Furthermore, the junction depth of the P-type first doped region 10 is not less than the junction depth of the N+ source region 6. Generally, the P-type first doped region 10 and the P-type second doped region 11 generally have the same junction depth.

[0077] In one embodiment of the present invention, a trench gate structure is disposed in both the first cell trench 12 and the second cell trench 12, wherein:

[0078] The trench gate structure includes a gate conductive polysilicon 2. The gate conductive polysilicon 2 filled in the first cell trench 12 is insulated and isolated from the inner wall of the first cell trench 12 by an insulating gate oxide layer 3 covering the inner wall of the first cell trench 12. The gate conductive polysilicon 2 filled in the second cell trench 13 is insulated and isolated from the inner wall of the second cell trench 13 by an insulating gate oxide layer 3 covering the inner wall of the second cell trench 13.

[0079] Figures 1 to 4 In FIG. 1 , it is shown that the first cell trench 12 and the second cell trench 13 adopt the same trench gate structure, and the specific conditions of the gate conductive polysilicon 2 and the insulating gate oxide layer 3 are consistent with the prior art.

[0080] In one embodiment of the present invention, a back electrode structure adapted to the IGBT device is provided on the back side of the semiconductor substrate. Figures 2 to 4 A form of the back electrode structure is shown in FIG. 1 , specifically: it includes an N+ field stop layer 8 disposed on the back of an N-type substrate 1 and a P+ collector region 9 disposed on the N+ field stop layer 8. Of course, a collector metal layer needs to be prepared on the P+ collector region 9. The collector of the IGBT device can be formed by the ohmic contact between the collector metal layer and the P+ collector region 9. The specific situation of the back electrode structure is consistent with the existing ones.

[0081] During operation, since the emitter metal does not penetrate the N+ source region 6, when the holes are to be led out from the emitter, they need to pass through the N+ source region 6, and an upper barrier region of holes is formed between the N+ source region 6 and the P-type base region 14 (in view of the existence of the hole barrier of the N-type carrier layer 4, the barrier here is called the upper barrier region of holes). Therefore, this part has a carrier storage function; the emitter metal forms a non-ohmic contact with the P-type body region 5 with a hole barrier, which also has a hole carrier storage function; the emitter metal is in ohmic contact with the P-type first doping region 10 and the P-type second doping region 11, providing a certain lead-out channel for the holes. Therefore, when forward conducting, on the basis of utilizing the N-type carrier storage layer 4, carrier storage can be further realized, so as to achieve the purpose of regulating carrier distribution and reducing the conduction voltage drop.

[0082] During reverse shutdown, the P-type second doping region 10 and the P-type second doping region 11 can be used to extract hole carriers, that is, multiple controls on the storage and extraction of hole carriers can be achieved, further optimizing the compromise between the on-state voltage drop and the off-state loss of the device.

[0083] In specific implementation, the corresponding lengths of the N+ source region 6 and the P-type body region 5 along the length direction of the first cell trench 12 can be freely and flexibly configured without affecting the breakdown voltage of the IGBT device. Among them, the free and flexible configuration of the length specifically means that the corresponding lengths of the N+ source region 6 and the P-type body region 5 will not seriously affect the breakdown voltage and short-circuit current of the IGBT device like the N-type carrier storage layer 4. Because the higher the concentration of the N-type carrier storage layer 4, the better the carrier storage effect, but the lower the BV will be and the larger the short-circuit current will be.

[0084] In addition, by adjusting the duty ratio of the N+ source region 6, the influence on the short-circuit current of the IGBT device can be avoided; at the same time, it will not cause the problem of negative gate capacitance caused by the Floating P enhanced carrier storage technology, thereby effectively suppressing EMI. The duty ratio of the N+ source region 6 specifically refers to the ratio of the length of the N+ source region 6 along the length direction of the first cell trench 12 to the entire cell length.

Claims

1. A trench-type IGBT device with multiple regulations, comprising a semiconductor substrate of a first conduction type and a cell region prepared in the central region of the semiconductor substrate. The cell region includes a number of cells distributed in parallel, and the cells in the cell region adopt a trench structure. Its characteristics are as follows: For any cell, it includes a first trench of the cell and a second trench of the cell adjacent to the first trench of the cell. Among them, A multiple regulation region for hole carrier storage or hole carrier extraction is arranged between the first trench of the cell and the second trench of the cell. The multiple regulation region is distributed along the corresponding length directions of the first trench of the cell and the second trench of the cell, and the multiple regulation region is in contact with the corresponding outer walls of the first trench of the cell and the second trench of the cell, and the multiple regulation region is adaptively connected to the emitter metal for forming the emitter of the IGBT device; When the trench-type IGBT device is in the forward conduction state, the multiple regulation region is used to store hole carriers to regulate the distribution of hole carriers, and the conduction voltage drop is reduced by using the distribution of the regulated hole carriers; When the trench-type IGBT device is in the reverse off state, the multiple regulation region is used to extract hole carriers; The multiple regulation region includes a carrier storage layer of a first conduction type, a base region of a second conduction type prepared on the carrier storage layer of the first conduction type, and a number of multiple regulation units prepared on the base region of the second conduction type. Among them, The carrier storage layer of the first conduction type and the base region of the second conduction type are both distributed along the corresponding length directions of the first trench of the cell and the second trench of the cell, and the carrier storage layer of the first conduction type is located above the corresponding bottom of the first trench of the cell and the second trench of the cell; For any multiple regulation unit, it includes a source region of a first conduction type, a first doping region of a second conduction type, a body region of a second conduction type, and a second doping region of a second conduction type that are sequentially distributed along the length direction of the first trench of the cell; When there are multiple multiple regulation units on the base region of the second conduction type, the multiple multiple regulation units are periodically arranged on the base region of the second conduction type along the corresponding length directions of the first trench of the cell and the second trench of the cell; for two adjacent multiple regulation regions, the second doping region of a second conduction type of one multiple regulation region is in contact with the source region of a first conduction type of another multiple regulation region; The source region of the first conduction type and the base region of the second conduction type form an upper hole barrier region, and the emitter metal and the body region of the second conduction type form a non-Ohmic contact with a hole barrier, and the emitter metal has an Ohmic contact with the source region of the first conduction type, the first doping region of the second conduction type, and the second doping region of the second conduction type.

2. The trench IGBT device with multiple regulations according to claim 1, characterized in that: The doping concentration of the first doping region of the second conduction type is consistent with the doping concentration of the second doping region of the second conduction type; The doping concentration of the body region of the second conduction type is consistent with the doping concentration of the base region of the second conduction type, and the doping concentration of the body region of the second conduction type is less than the doping concentration of the first doping region of the second conduction type; Within the multiple regulation unit, the source region of the first conduction type, the first doping region of the second conduction type, the body region of the second conduction type, and the second doping region of the second conduction type all vertically extend from the corresponding notches of the first trench of the cell and the second trench of the cell to the base region of the second conduction type.

3. The trench IGBT device with multiple regulations according to claim 1 is characterized in that: in An emitter contact hole is provided between the first cell trench and the second cell trench, and emitter metal is filled in the emitter contact hole so that the emitter metal is in adaptive contact with the multiple regulation units. Among them, the depth of the emitter contact hole is the same in the first-conductivity-type source region, the second-conductivity-type first doping region, the second-conductivity-type body region, and the second-conductivity-type second doping region. The depth of the emitter contact hole is less than the corresponding thicknesses of the first-conductivity-type source region, the second-conductivity-type first doping region, the second-conductivity-type body region, and the second-conductivity-type second doping region.

4. The trench IGBT device with multiple regulations according to claim 3, characterized in that: The emitter contact hole penetrates through the first-conductivity-type source region, the second-conductivity-type first doping region, the second-conductivity-type body region, and the second-conductivity-type second doping region, or the corresponding emitter contact holes in the first-conductivity-type source region, the second-conductivity-type first doping region, the second-conductivity-type body region, and the second-conductivity-type second doping region are not completely connected.

5. The trench IGBT device with multiple regulations according to claim 3, characterized in that: the corresponding widths of the emitter contact hole in the first-conductivity-type source region, the second-conductivity-type first doping region, the second-conductivity-type body region, and the second-conductivity-type second doping region are the same, or the corresponding widths of the emitter contact hole in the second-conductivity-type first doping region and the second-conductivity-type second doping region are greater than the corresponding widths of the emitter contact hole in the first-conductivity-type source region and the second-conductivity-type body region.

6. The trench IGBT device with multiple regulations according to any one of claims 1 to 5, characterized in that: The junction depth of the second-conductivity-type first doping region is not less than the junction depth of the first-conductivity-type source region.

7. The trench IGBT device with multiple regulations according to any one of claims 1 to 5, characterized in that: A trench gate structure is provided in both the first cell trench and the second cell trench. Among them, the trench gate structure includes gate conductive polysilicon. The gate conductive polysilicon filled in the first cell trench is insulated from the inner wall of the first cell trench by an insulating gate oxide layer covering the inner wall of the first cell trench, and the gate conductive polysilicon filled in the second cell trench is insulated from the inner wall of the second cell trench by an insulating gate oxide layer covering the inner wall of the second cell trench.

8. The trench IGBT device with multiple regulations according to any one of claims 1 to 5, characterized in that: A back electrode structure adapted to the IGBT device is provided on the back surface of the semiconductor substrate.

9. The trench IGBT device with multiple regulations according to any one of claims 1 to 5, characterized in that: Both the first cell trench and the second cell trench are strip-shaped, and the length direction of the first cell trench is the same as the length direction of the second cell trench.

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