Groove type RC-IGBT device and manufacturing method thereof

Abstract

The invention discloses a groove-type RC-IGBT device and a manufacturing method thereof, and relates to the technical field of semiconductor devices, the groove-type RC-IGBT device comprises at least one cell, the cell comprises an IGBT region and an FRD region, the IGBT region comprises a first-type groove gate and a plurality of second-type groove gates, the tops of the plurality of second-type groove gates are not provided with gate source isolation layers, and a hole injection region covers the plurality of second-type groove gates; the device is provided with the CT open hole crossing the grid electrode and the source electrode, the depth-to-width ratio of the open hole is reduced, the process complexity is reduced, the metal filling layer process flow is simplified, Ti / TiN and W layers do not need to be additionally filled, and the process cost is reduced; drifting of the threshold voltage of the device is reduced, the anti-radiation capability of the device is enhanced, and it is guaranteed that the threshold voltage is kept unchanged when the device is subjected to service life control; according to the invention, the ion implantation concentration at the bottom of the contact hole is reduced, the reverse recovery energy Erec is reduced, and the sheet formed after the substrate is thinned is subjected to high-energy electron irradiation and annealing, so that the consistency of the threshold voltage of the device is higher, the parallel use of RC-IGBT can be facilitated, and the overall performance of the packaging module is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor devices, and in particular to a trench type RC-IGBT device and a manufacturing method thereof. Background Art

[0002] In the development of power electronics technology, insulated gate bipolar transistors (IGBTs) have the advantages of MOSFET voltage drive, easy control, fast switching speed, and bipolar transistors with high withstand voltage, low on-voltage, large output current, and low switching loss. They have gradually become the core devices in power electronics systems. However, IGBTs require reverse parallel freewheeling diodes (FRDs) when in use, which increases the cost of use. At the same time, the reverse parallel FRDs also increase the size of the package, affecting the overall reliability of the device. Parasitic parameters also affect the overall performance of the device. Reverse conducting IGBTs (RC-IGBTs) integrate IGBTs and FRDs on a single chip. During use, there is no need to connect additional freewheeling diodes in parallel. They can take into account the static and dynamic performance of both IGBTs and FRDs. When in use, they can reduce chip thermal resistance and reduce chip junction temperature fluctuations. Compared with the IGBT+FRD packaging form, RC-IGBTs can save about 1 / 3 of the total chip area, greatly reducing chip production and manufacturing costs and packaging and testing costs. The reduction of parallel chips has also improved the reliability of the device, and it has gradually become the mainstream of IGBT applications.

[0003] Carrier lifetime control technology is the key to achieving high-performance RC-IGBT. Currently, RC-IGBT carrier lifetime control technologies mainly include Pt diffusion technology, electron irradiation technology, and H ion or He ion injection technology. Among them, electron irradiation technology uses electron irradiation to induce defects inside the semiconductor as recombination centers to achieve the purpose of controlling the minority carrier lifetime. Compared with H ion or He ion injection technology, electron irradiation technology induces fewer deep energy level defects, the leakage current of the manufactured device is smaller, and the breakdown voltage of the device is not affected. Compared with Pt diffusion technology, electron irradiation technology can accurately control the concentration of induced defects by controlling the dose of high-energy electron irradiation, and the defects formed inside the entire device are evenly distributed, and the device parameters are more consistent. At the same time, electron irradiation will not pollute the production line. It is a clean minority carrier lifetime control method, so it has become a commonly used RC-IGBT lifetime control technology.

[0004] Currently, the applicant knows two types of trench RC-IGBT devices as follows: First, Figure 1As shown, the trench RC-IGBT includes adjacent IGBT regions and FRD regions, the IGBT region includes a first type trench gate and four second type trench gates, the tops of the two types of trench gates are respectively formed with silicate glass (USG) or borophosphosilicate glass (BPSG) dielectric layers as gate-source isolation layers, the first type of trench gate includes two N+ type doped source regions on both sides, called true gates; the second type of trench gate does not include, called dummy gates or Dummy gates, the first type of trench gate becomes the gate of the IGBT, the second type of trench gate is connected to the metal filling layer through different openings to become the emitter of the IGBT, the trenches of the two types of trench gates include gate oxide layers and polysilicon, the second type of trench gate is connected to the metal filling layer through small openings, and the potential is kept grounded. With this structure, the P-type body region is grounded, and the triode in the P region works to form a hole current; second, as Figure 2 As shown, the tops of the four second-type trench gates share a dielectric layer and are not connected to the metal filling layer, keeping the potential floating. With this structure, the P-type body region is floating and no current is generated in the P region.

[0005] However, the two trench RC-IGBT devices known to the applicant have the following problems: when the life span is controlled by high-dose electron irradiation, the threshold voltage Vth is obviously reduced. The reduction of the device threshold voltage may cause the device to be turned on by mistake in severe cases, making the device difficult to use. The main reason is that high-energy electron irradiation excites electron-hole pairs in the SiO2 dielectric layer (the gate-source isolation layer and the gate oxide layer are both SiO2 dielectric layers, and the two are connected). The electrons will quickly migrate out of the SiO2 dielectric layer, and the holes will migrate out of the SiO2 dielectric layer due to their slow movement speed. , and the other part is captured by the hole traps in the SiO2 dielectric layer to become positively charged oxide layer trap charges. These trapped charges will be concentrated. When the trapped charges accumulate to a certain concentration, the surface of the semiconductor will be inverted, forming interface state charges, among which the oxide layer trap charges play a dominant role, causing the device threshold voltage to drift in the negative direction; while the interface state charge will cause the device threshold voltage to drift in the positive direction, but the interface state charge is relatively small, so the overall threshold voltage of the device will be greatly reduced after high-energy electron irradiation, shifting in the negative direction, and this drift cannot be repaired by subsequent annealing after high-energy electron irradiation. In order to pull the threshold voltage of the device back to the normal value, the impurity concentration in the trench area can be increased by increasing the injection concentration of Pbody, but this method will cause the reverse recovery energy Erec of FRD in RC-IGBT to increase significantly, increasing device loss; another way is to reduce the injection dose of high-energy electron irradiation, which will also cause the loss of key performance of the device. Although too small a dose will not cause the threshold voltage to drift after annealing, it is difficult to reflect the effect of life control, which will cause the device to fail to meet the requirements of key parameters and fail to meet product use.

[0006] Therefore, people are in urgent need of a trench RC-IGBT device that can effectively solve the threshold voltage drift problem caused by high-energy electron irradiation lifetime control and reduce the overall loss of the device. Summary of the invention

[0007] The object of the present invention is to provide a trench type RC-IGBT device and a method for manufacturing the same, so as to solve the problems existing in the above-mentioned prior art, eliminate the gate-source isolation layer at the top of the second type trench gate, and set a hole injection region to cover a plurality of the second type trench gates, which can effectively solve the threshold voltage drift problem caused by high-energy electron irradiation lifetime control and reduce the overall loss of the device.

[0008] To achieve the above-mentioned purpose, the present invention provides the following solution: The present invention provides a trench type RC-IGBT device, comprising at least one cell, wherein the cell comprises an IGBT region and an FRD region, wherein the IGBT region comprises a first type of trench gate having a gate-source isolation layer on the top and a plurality of second type of trench gates having no gate-source isolation layer on the top, wherein the second type of trench gates are located on a side of the first type of trench gate close to the FRD region, the IGBT region and the FRD region share a hole injection region, and the hole injection region covers a plurality of the second type of trench gates.

[0009] Preferably, the IGBT region includes a metal collector, a p+ doped region, an n+ field stop layer, an n-drift region, an n-type carrier storage layer, a P-type doped region, the hole injection region and a metal filling layer arranged in sequence; the FRD region includes a metal collector, an n-type doped region, an n+ field stop layer, an n-drift region, an n-type carrier storage layer, a P-type doped region, the hole injection region and a metal filling layer arranged in sequence.

[0010] Preferably, the first type of trench gate includes a trench, a gate-source isolation layer and an N+ source region, and the second type of trench gate includes a trench, the trenches of the first type of trench gate and the second type of trench gate are both arranged in the n-drift region, the n-type carrier storage layer and the P-type doping region, the N+ source region is arranged on both sides of the trench of the first type of trench gate, and the gate-source isolation layer is arranged on the top of the trench of the first type of trench gate; the trenches of the first type of trench gate and the second type of trench gate both include a gate oxide layer and polysilicon.

[0011] The present invention also provides a method for manufacturing the above trench type RC-IGBT device, comprising the following steps:

[0012] S1: forming a MOS structure on a semiconductor substrate, wherein an IGBT region and an FRD region in the MOS structure share a hole injection region, the hole injection region covers a plurality of second-type trench gates, and during the formation of the MOS structure, a metal filling layer is directly formed on the hole injection region;

[0013] S2: forming a passivation layer and a protective layer on the front side of the MOS structure;

[0014] S3: forming an anode of the IGBT, an n-type region of the FRD, a field stop layer, and a metal collector on the back of the MOS structure;

[0015] S4: Perform high-energy electron irradiation. After the high-energy electron irradiation is completed, perform thermal annealing treatment, and the trench type RC-IGBT device is completed.

[0016] Preferably, in step S1, a dielectric oxide layer is formed on the top of the completed first-type trench gate and the second-type trench gate, and then a gate-source isolation layer at the top of the first-type trench gate and a CT opening spanning the gate and the source are formed on the top dielectric oxide layer, and finally, B and BF2 ion implantation is performed at the bottom of the contact hole at the CT opening spanning the gate and the source to form a hole implantation region, and the energy of the B and BF2 ion implantation is 20KeV to 100KeV, and the dosage is 2E11 to 5E14.

[0017] Preferably, the size of the CT opening is adjusted according to the distance between the trench gates of the RC-IGBT, and the size of the CT opening is greater than 1.5 times the distance between the trench gates in the active area.

[0018] Preferably, in step S1, the metal filling layer of the MOS structure is filled with AlSiCu alloy by a magnetron sputtering process, and the thickness is

[0019] Preferably, in step S3, the energy of high-energy electron irradiation is 5 MeV to 20 MeV, the irradiation dose is 30 Kgy to 100 Kgy, the annealing time is 30 to 90 min, and the annealing temperature is 200 to 400°C.

[0020] Preferably, the semiconductor substrate is an N-type single crystal silicon or a wide bandgap semiconductor. When the semiconductor substrate is a single crystal silicon substrate, the single crystal silicon substrate serves as an N-drift region of the MOS structure.

[0021] Preferably, when the semiconductor substrate is a single crystal silicon substrate, before step S3, the substrate is thinned to form a thin slice.

[0022] Compared with the prior art, the present invention mainly achieves the following technical effects:

[0023] The gate-source isolation layer at the top of the second type of trench gate is removed, and a hole injection region is set to cover a plurality of the second type of trench gates, thereby effectively reducing the area of ​​the gate-source isolation layer, and reducing the overall SiO2 dielectric layer of the device (the overall area of ​​the gate-source isolation layer and the gate oxide layer connected thereto), thereby preventing the accumulation of more trapped charges induced by electron irradiation, effectively reducing the drift of the threshold voltage Vth of the device, and enhancing the radiation resistance of the device. Moreover, based on the reduction of the gate-source isolation layer, under normal process flow, subsequent annealing after high-energy electron irradiation will also repair part of the trapped charges, and at the same time generate a large amount of interface state charges, so that the threshold voltage is adjusted back, so that the small amount of threshold voltage drift generated after high-energy electron irradiation can be repaired, and the trench type RC-IGBT device can be guaranteed to pass. The threshold voltage remains unchanged when the lifetime is controlled by high-energy electron irradiation; in addition, the trench RC-IGBT has a CT opening spanning the gate and source electrodes, which reduces the aspect ratio of the opening and reduces the process complexity; at the same time, the process complexity when forming the metal filling layer is reduced, and the process cost is reduced. The metal filling layer forms a good ohmic contact with the Si substrate below, which can reduce the concentration of ion implantation at the bottom of the contact hole, further reduce the reverse recovery energy Erec of the device, reduce the overall loss of the device, help reduce the reverse recovery charge of the FRD, reduce the reverse recovery current, shorten the reverse recovery time, and, due to the high consistency of the device threshold voltage, it can be more conducive to the parallel use of RC-IGBT and improve the overall performance of the packaging module. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0025] Figure 1 A schematic diagram of the structure of a trench type RC-IGBT device known to the applicant of the present invention;

[0026] Figure 2 A schematic diagram of the structure of another trench RC-IGBT device known to the applicant of the present invention;

[0027] Figure 3 Schematic diagram of the structure of a trench RC-IGBT device in an embodiment of the present invention;

[0028] Among them, 1. Metal collector; 2. First type trench gate; 3. Second type trench gate; A0, IGBT region; B0, FRD region; 10, p+ doped region; 11, n-type doped region; 20, n+ field stop layer; 30, n- drift region; 40, n-type carrier storage layer; 41, polysilicon; 42, gate oxide layer; 50, P-type doped region; 51, N+ source region; 52, hole injection region; 60, gate-source isolation layer; 70, metal filling layer; 80, high-energy electron irradiation. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The purpose of the present invention is to provide a trench type RC-IGBT device and a method for manufacturing the same, so as to solve the problems existing in the prior art, eliminate the gate-source isolation layer at the top of the second type trench gate, and set a hole injection region to cover a plurality of the second type trench gates, which can effectively solve the threshold voltage drift problem caused by high-energy electron irradiation lifetime control and reduce the overall loss of the device.

[0031] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] Please refer to Figure 3As shown, a trench type RC-IGBT device is provided, including at least one unit cell, the unit cell including an IGBT region A0 and an FRD region B0, the IGBT region A0 including a first type trench gate 2 with a gate-source isolation layer 60 (SiO2) on the top and a plurality of second type trench gates 3 without a gate-source isolation layer 60 on the top, the second type trench gates 3 are located on a side of the first type trench gate 2 close to the FRD region B0, the FRD region B0 and the IGBT region A0 are demarcated by the second type trench gate 3 farthest from the first type trench gate 2, the IGBT region A0 and the FRD region B0 share a hole injection region 52, the hole injection region 52 covers a plurality of second type trench gates 3, so that the emitter of the IGBT region A0 and the FRD region B0 are connected. The front P region of the D region B0 is completely connected, which reduces the additional mask required for the separate CT openings of the IGBT region A0 and the FRD region B0; since the top of the second type trench gate 3 no longer has the gate-source isolation layer 60, the area of ​​the gate-source isolation layer 60 is effectively reduced, so that the SiO2 dielectric layer of the overall trench type RC-IGBT device is reduced, that is, the overall area of ​​the gate-source isolation layer and the gate oxide layer connected thereto is reduced, which prevents the accumulation of more trapped charges induced by electron irradiation, effectively reduces the drift of the threshold voltage Vth of the device, and enhances the radiation resistance of the device. Moreover, on the basis of the reduction of the gate-source isolation layer 60, even if there is a certain threshold voltage drift, under normal process flow , the subsequent annealing process after high-energy electron irradiation 80 will also repair the trapped charges, and at the same time generate a large amount of interface state charges, so that the threshold voltage can be adjusted back, which can realize the repair of the small amount of threshold voltage drift generated after high-energy electron irradiation 80, and can ensure that the threshold voltage of the trench type RC-IGBT device remains unchanged when the lifetime is controlled by high-energy electron irradiation 80; in addition, the gate-source isolation layer 60 on the top of the second type trench gate 3 is removed, and the hole injection region 52 is set to cover multiple second type trench gates 3, so that the trench type RC-IGBT has a CT opening spanning the gate and source poles, which reduces the aspect ratio of the opening, and reduces the inability to fully etch due to its excessive aspect ratio, thereby causing the opening to be incomplete. Sufficient, or in order to overcome the problem of over-etching caused by insufficient etching of the opening, which in turn causes a bow problem on the hole wall, the process complexity is reduced; at the same time, the process complexity when forming the metal filling layer 70 is reduced, and the process cost is reduced. The metal filling layer 70 forms a good ohmic contact with the Si substrate below, which can reduce the concentration of ion implantation at the bottom of the contact hole, further reduce the reverse recovery energy Erec of the device, reduce the overall loss of the device, help reduce the reverse recovery charge of the FRD, reduce the reverse recovery current, shorten the reverse recovery time, and, due to the high consistency of the device threshold voltage, it can be more conducive to the parallel use of RC-IGBT and improve the overall performance of the packaging module.

[0033] The principle of setting multiple second-type trench gates 3 is: since the cell density of trench IGBT is much higher than that of planar gate and the current path is shorter, a reasonable proportion of dummy gates is often used to control the channel current density to ensure the short-circuit safe working area of ​​the device.

[0034] The specific structure of the trench RC-IGBT device in the present invention is as follows: the IGBT region A0 includes a metal collector 1, a p+ doped region 10, an n+ field stop layer 20, an n- drift region 30, an n-type carrier storage layer 40, a P-type doped region 50, a hole injection region 52 and a metal filling layer 70 arranged in sequence; the FRD region B0 includes a metal collector 1, an n-type doped region 11, an n+ field stop layer 20, an n- drift region 30, an n-type carrier storage layer 40, a P-type doped region 50, a hole injection region 52 and a metal filling layer 70 arranged in sequence.

[0035] The first type of trench gate 2 includes a trench, a gate-source isolation layer 60 and an N+ source region 51, and the second type of trench gate 3 includes a trench. The trenches of the first type of trench gate 2 and the second type of trench gate 3 are both arranged in the n-drift region 30, the n-type carrier storage layer 40 and the P-type doping region 50. N+ source regions 51 are arranged on both sides of the trench of the first type of trench gate 2, and a gate-source isolation layer 60 is arranged on the top of the trench of the first type of trench gate 2; the trenches of the first type of trench gate 2 and the second type of trench gate 3 both include a gate oxide layer 42 (SiO2) and polysilicon 41, the gate oxide layer 42 is connected to the gate-source isolation layer 60, and both are SiO2 dielectric layers.

[0036] The present invention also provides a method for manufacturing the above trench type RC-IGBT device, comprising the following steps:

[0037] S1: forming a MOS structure on a semiconductor substrate, wherein the IGBT region A0 and the FRD region B0 in the MOS structure share a hole injection region 52, the hole injection region 52 covers a plurality of second-type trench gates 3, and during the formation of the MOS structure, a metal filling layer is directly formed on the hole injection region;

[0038] S2: Form a passivation layer and a protective layer on the front of the MOS structure to provide protection;

[0039] S3: forming an anode of the IGBT and an n-type region of the FRD, a field stop layer and a metal collector 1 on the back side of the MOS structure;

[0040] S4: high energy electron irradiation 80 is performed. After the high energy electron irradiation 80 is completed, thermal annealing is performed, and the trench type RC-IGBT device is manufactured.

[0041] The semiconductor substrate is an N-type single crystal silicon or a wide bandgap semiconductor. The wide bandgap semiconductor may be a silicon substrate, a silicon carbide substrate, a gallium nitride substrate, a silicon germanium substrate, a gallium arsenide substrate, or the like.

[0042] In this embodiment, the semiconductor substrate is a single crystal silicon substrate, which can be used as the n-drift region 30 of the MOS structure, thus saving process steps.

[0043] In step S1, the specific process of the MOS structure is as follows: an N-type single crystal silicon substrate is used as an n-drift region 30, an N-type doped region is formed on the Si substrate by high energy P ion implantation, and then the carrier storage layer is pushed to a suitable position by high temperature annealing, and finally an n-type carrier storage layer 40 is formed;

[0044] The thickness of the deposited layer on the front side of the substrate is The SiO2 is used as a hard mask layer for the subsequent trench gate etching, and then a photoresist is spin-coated on the hard mask layer. After baking, exposure, and development, the SiO2 is etched; the n-drift region 30 is then etched using the SiO2 as a hard mask to form a trench with a depth of about 5 microns in a part of the n-drift region 30; after removing the sacrificial oxide layer, a high-quality silicon oxide layer is grown by thermal oxidation as a gate oxide layer 42; a layer of thickness is deposited using the LPCVD process After the polysilicon 41 is etched, a trench-type polysilicon 41 is formed.

[0045] The P-type doping region 50 is formed by B ion implantation and high temperature junction pushing;

[0046] By using As ion implantation and high temperature junction pushing method, N+ source regions 51 are formed on both sides of the first type trench gate 2;

[0047] Tetraethyl orthosilicate and boron phosphorus doped silicon dioxide (TEOS+BPSG) are deposited on the P-type doped region 50 to grow The USG and BPSG layers are formed, that is, a dielectric oxide layer is formed on the top of the first type trench gate 2 and the second type trench gate 3, and then photolithography is performed to etch the USG and BPSG layers, leaving only the USG and BPSG on the top of the first type trench gate 2, forming a gate-source isolation layer 60 on the top of the first type trench gate 2, and forming a large CT opening across the gate and the source;

[0048] By adopting the method of B ion and BF2 implantation and high temperature junction pushing, ion implantation is performed at the bottom of the contact hole at the CT opening across the gate and the source to form a hole implantation region 52, wherein the hole implantation is divided into two steps, the implantation energy is 20KeV to 100KeV, and the dose is 2E11 to 5E14. Specifically, the implantation energy and dose in this embodiment are BF2 / 20KeV / 5E14 and B / 100KeV / 5E12.

[0049] The AlSiCu alloy layer is deposited by magnetron sputtering, and a metal filling layer 70 is formed by metal etching. The thickness of the metal filling layer 70 is The manufacturing of the MOS structure is now completed.

[0050] When the metal filling layer 70 is formed, the small CT openings in the known trench RC-IGBT device need to be filled with metal W. At the same time, before the W deposition, a Ti / TiN layer needs to be deposited first to prevent the W layer from falling off, and then an AlCu layer is deposited to form the metal filling layer 70. However, in the trench RC-IGBT device, the CT openings spanning the gate and source electrodes do not need to be additionally filled with Ti / TiN and W layers, which simplifies the process flow and saves costs.

[0051] Before step S3, when an N-type single crystal silicon substrate is selected, the substrate is first thinned to a suitable thickness by the Taiko process while ensuring the voltage resistance of the chip. Then, the anode (p+ doped region 10) of the IGBT and the n-type region (n-type doped region 11) of the FRD are formed by back-side photolithography and P ion and B ion implantation, and laser annealing. The field stop layer (n+ field stop layer 20) on the back side of the trench RC-IGBT device is formed by P ion or proton implantation (H ion He ion) and high-temperature push-junction method. The metal collector 11 on the back side of the trench RC-IGBT device is formed by depositing metal Al / Ti / NiV / Ag.

[0052] By thinning the substrate and placing the electron irradiation step of high-energy electron irradiation 80 at the end of the entire process, on the one hand, compared with thick slices, more thin slices can be arranged for electron irradiation at the same time, which improves efficiency and reduces costs; on the other hand, the annealing temperature of electron irradiation is low and the time is short. After the thick slice is electron irradiated, the process annealing on the back side will inevitably affect the defect concentration distribution of electron irradiation. Under extreme conditions, the defects caused by electron irradiation will also be repaired, making it difficult to reflect the effect of life control. Therefore, this method can relatively avoid the influence of other processes on the defect concentration distribution of electron irradiation, making the threshold voltage consistency of the device higher. Although electron irradiation and thermal annealing on the back side of the thinned substrate may cause the risk of substrate warping, due to the low temperature and short time of electron irradiation annealing, the problem of substrate warping can be well avoided through process optimization and adjustment.

[0053] In step S3, the energy of high-energy electron irradiation 80 is 5MeV to 20MeV, the irradiation dose is 30Kgy to 100Kgy, the annealing time is 30 to 90min, and the annealing temperature is 200 to 400°C. In this embodiment, the energy of high-energy electron irradiation 80 is 10MeV, the irradiation dose is 100Kgy, the annealing time is 60min, and the annealing temperature is 350°C.

[0054] Attachment Figure 1 and attached Figure 2 The known structure shown and the attached Figure 3 The power device provided by the structure of the present invention is tape-out and packaged and tested, including the test of the device threshold voltage Vth and the diode reverse recovery energy Erec, and the results are as follows:

[0055] A trench RC-IGBT provided in an embodiment of the present invention uses high-energy electron irradiation for 80 seconds with an energy of 10 MeV and an irradiation dose of 100 Kgy; the annealing temperature after electron irradiation is 350°C and the annealing time is 60 min; the control group uses the same structure and process without electron irradiation. The packaging results show that the threshold voltage of the trench RC-IGBT in the control group is 5.8V and the device Erec is 10.4 mJ; the threshold voltage of the trench RC-IGBT provided in the example of the present invention is 5.8V, the standard deviation of the threshold voltage (Stdev) is 0.045, and the device Erec is 6.5 mJ. The control results show that the embodiment of the present invention solves the problem of the threshold voltage drop of the trench RC-IGBT after high-energy electron irradiation for 80 seconds, and the reduction of Erec also reflects the effect of life control.

[0056] Compare with Figure 1 and attached Figure 2 The trench RC-IGBT provided by the structure uses the same high-energy electron irradiation energy and dose of 80 to ensure the same annealing temperature and time. The packaging results show that the attached Figure 1 The threshold voltage of the trench RC-IGBT with the structure is 4.6V, the standard deviation of the threshold voltage is 0.092, and the device Erec is 8.0mJ; Figure 2 The threshold voltage of the trench RC-IGBT with this structure is 4.3V, the standard deviation of the threshold voltage is 0.087, and the device Erec is 8.5mJ. Figure 1 and attached Figure 2 The threshold voltage of the trench RC-IGBT with a structure is significantly reduced. Figure 1 The threshold voltage is slightly higher than the Figure 2 , which is consistent with the smaller area of ​​the gate-source isolation layer 60 at the top of the gate; compared with the trench RC-IGBT provided by the present invention, its reverse recovery energy Erec is higher, which is consistent with the hole injection concentration at the bottom of the opening and the filling method of the metal filling layer 70. Figure 1 and attached Figure 2 The trench RC-IGBT provided by the present invention has a smaller threshold voltage standard deviation and higher threshold voltage consistency.

[0057] The size of the large CT opening across the gate and source formed in this embodiment is adjusted according to the trench pitch size (the distance between the trench gates) of the RC-IGBT, and is generally greater than 1.5 times the pitch size of the trench gate in the active area. For example, for a trench gate with a pitch size of 1.0 um, the opening size should be greater than 1.5 um; for a trench gate with a pitch size of 1.6 um, the opening size should be greater than 2.4 um; for a trench gate with a pitch size of 2.4 um, the opening size should be greater than 3.6 um; and the same applies to trench gate structures with smaller or larger pitch sizes.

[0058] Adaptive changes made according to actual needs are all within the protection scope of the present invention.

[0059] It should be noted that it is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any reference numerals in the claims should not be regarded as limiting the claims involved.

[0060] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A trench RC-IGBT device, characterized in that: The invention comprises at least one unit cell, wherein the unit cell comprises an IGBT region and an FRD region, wherein the IGBT region comprises a first type trench gate having a gate-source isolation layer on the top and a plurality of second type trench gates having no gate-source isolation layer on the top, wherein the second type trench gates are located on a side of the first type trench gates close to the FRD region, and the IGBT region and the FRD region share a hole injection region, and the hole injection region covers a plurality of the second type trench gates.

2. The trench type RC-IGBT device according to claim 1, characterized in that: The IGBT region includes a metal collector, a p+ doped region, an n+ field stop layer, an n-drift region, an n-type carrier storage layer, a P-type doped region, the hole injection region and a metal filling layer arranged in sequence; the FRD region includes a metal collector, an n-type doped region, an n+ field stop layer, an n-drift region, an n-type carrier storage layer, a P-type doped region, the hole injection region and a metal filling layer arranged in sequence.

3. The trench type RC-IGBT device according to claim 2, characterized in that: The first type of trench gate includes a trench, a gate-source isolation layer and an N+ source region, and the second type of trench gate includes a trench. The trenches of the first type of trench gate and the second type of trench gate are both arranged in the n-drift region, the n-type carrier storage layer and the P-type doped region, the N+ source region is arranged on both sides of the trench of the first type of trench gate, and the gate-source isolation layer is arranged on the top of the trench of the first type of trench gate; the trenches of the first type of trench gate and the second type of trench gate both include a gate oxide layer and polysilicon.

4. A method for manufacturing a trench RC-IGBT device, characterized in that: Manufacturing a trench type RC-IGBT device as claimed in any one of claims 1 to 3 comprises the following steps: S1: forming a MOS structure on a semiconductor substrate, wherein an IGBT region and an FRD region in the MOS structure share a hole injection region, the hole injection region covers a plurality of second-type trench gates, and during the formation of the MOS structure, a metal filling layer is directly formed on the hole injection region; S2: forming a passivation layer and a protective layer on the front side of the MOS structure; S3: forming an anode of the IGBT, an n-type region of the FRD, a field stop layer, and a metal collector on the back of the MOS structure; S4: Perform high-energy electron irradiation. After the high-energy electron irradiation is completed, perform thermal annealing treatment, and the trench type RC-IGBT device is completed.

5. The method for manufacturing a trench type RC-IGBT device according to claim 4, characterized in that: In step S1, a dielectric oxide layer is formed on the top of the completed first-type trench gate and the second-type trench gate, and then a gate-source isolation layer at the top of the first-type trench gate and a CT opening across the gate and the source are formed on the top dielectric oxide layer. Finally, B and BF2 ions are implanted at the bottom of the contact hole at the CT opening across the gate and the source to form a hole injection region. The energy of the B and BF2 ion implantation is 20KeV to 100KeV, and the dosage is 2E11 to 5E14.

6. The method for manufacturing a trench RC-IGBT device according to claim 5, characterized in that: The size of the CT opening is adjusted according to the distance between the trench gates of the RC-IGBT, and the size of the CT opening is greater than 1.5 times the distance between the trench gates in the active area.

7. The method for manufacturing a trench RC-IGBT device according to claim 4, characterized in that: In step S1, the metal filling layer of the MOS structure is filled with AlSiCu alloy by a magnetron sputtering process, and the thickness is 8. The method for manufacturing a trench type RC-IGBT device according to claim 4, characterized in that: In step S3, the energy of high energy electron irradiation is 5 MeV to 20 MeV, the irradiation dose is 30 Kgy to 100 Kgy, the annealing time is 30 to 90 min, and the annealing temperature is 200 to 400°C.

9. The method for manufacturing a trench type RC-IGBT device according to claim 4, characterized in that: The semiconductor substrate is an N-type single crystal silicon or a wide bandgap semiconductor. When the semiconductor substrate is a single crystal silicon substrate, the single crystal silicon substrate serves as an N-drift region of the MOS structure.

10. The method for manufacturing a trench type RC-IGBT device according to claim 9, characterized in that: When the semiconductor substrate is a single crystal silicon substrate, before step S3, the substrate is thinned to form a thin slice.

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