A reverse-conducting IGBT device and its fabrication method

Abstract

This invention relates to a reverse-conductive IGBT device and its fabrication method in the field of semiconductor technology, comprising: a first anode structure; a second anode structure, wherein the second anode structure and the first anode structure are located on the same surface and are connected through an N-type drift layer; a drift region structure, wherein the drift region structure is disposed on the first anode structure and the second anode structure, the drift region structure and the second anode structure forming a first PN junction barrier, and the drift region structure and the first anode structure forming a second PN junction barrier; a gate structure, wherein the gate structure is disposed on the surface of the drift region structure facing away from the first anode structure; and a cathode structure, wherein the cathode structure is disposed on the gate structure, thereby solving the current misalignment problem caused by the bounce phenomenon when the device transitions from a unipolar operating mode to a bipolar operating mode.

Description

Technical Field

[0001] This invention relates to the field of semiconductor technology, specifically to a reverse-conducting IGBT device and its fabrication method. Background Technology

[0002] IGBT is short for Insulated Gate Bipolar Transistor, a voltage-controlled power semiconductor device used in high-frequency, high-voltage applications. It can be used in DC-DC conversion, AC-DC conversion, motor control, frequency converters, electric vehicles, and other fields.

[0003] Traditional IGBT devices cannot conduct when subjected to reverse voltage because the collector is reverse biased. Therefore, when driving resistive-inductive loads, a diode needs to be connected in anti-parallel to conduct the reverse current and prevent the device from breaking down. In the market, single IGBT chips are typically packaged with a fast recovery diode (FRD) chip connected in anti-parallel, but this method is costly and has large parasitic parameters. Reverse-conducting IGBT devices integrate a diode structure within the IGBT chip by introducing an N+ region in the anode region, thus eliminating the need for an additional anti-parallel diode chip. This reverse-conducting IGBT structure saves chip area and testing costs, thereby reducing chip cost. Furthermore, compared to traditional IGBTs, reverse-conducting IGBTs have smaller parasitic parameters, better temperature uniformity, and excellent soft-turn-off characteristics and power cycling capability.

[0004] However, due to the introduction of the N+ region at the anode, the PN junction of the anode P+ / N- buffer layer of the reverse-conducting IGBT cannot conduct in low-current mode, thus failing to introduce conductivity modulation, and the device operates in unipolar mode. As the current increases, the voltage drop across the anode P+ / N- buffer layer junction increases, causing the anode P+ / N- buffer layer junction to conduct, injecting holes into the N- drift region, reducing the device resistance, and entering bipolar conduction mode. However, when the device transitions from unipolar to bipolar operation, there is a negative resistance region, known as bounce. This bounce can cause current misalignment when the devices are connected in parallel, leading to uneven current distribution among the parallel devices and potentially causing device damage. Therefore, eliminating the bounce problem under short cell conditions is an urgent issue to address. Summary of the Invention

[0005] This invention addresses the shortcomings of existing technologies by providing a reverse-conducting IGBT device and its fabrication method, thus solving the current misalignment problem caused by the bounce phenomenon that occurs when the device transitions from a unipolar operating mode to a bipolar operating mode.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] A reverse-conducting IGBT device, comprising:

[0008] First anode structure;

[0009] The second anode structure is located on the same surface as the first anode structure, and the second anode structure and the first anode structure are connected by an N-type drift layer;

[0010] A drift region structure is disposed on a first anode structure and a second anode structure. The drift region structure and the second anode structure form a first PN junction barrier, and the drift region structure and the first anode structure form a second PN junction barrier.

[0011] A gate structure, wherein the gate structure is disposed on the surface of the drift region structure opposite to the first anode structure;

[0012] A cathode structure is disposed on a gate structure.

[0013] Optionally, during the initial forward conduction phase, the first PN junction barrier blocks the electron flow path, and the device operates in unipolar mode.

[0014] When in the low-voltage forward conduction stage, the barrier of the first PN junction decreases, and the unipolar operating mode of the device is weakened.

[0015] When in the high-voltage forward conduction stage, the second PN junction barrier is turned on, and the device enters the bipolar operating mode.

[0016] Optionally, the second anode structure is located on one side of the first anode structure;

[0017] Alternatively, the second anode structure is located on both sides of the first anode structure, with one or both sides of the second anode structure located on the same surface as the first anode structure and connected by an N-type drift layer.

[0018] Optionally, the second anode structure includes a first P-type anode region and a Schottky anode, wherein the Schottky anode is disposed on the surface of the first P-type anode region away from the drift region structure.

[0019] Optionally, the doping concentration of the first P-type anode region is 4 × 10⁻⁶. 15 cm -3 ~6×10 15 cm -3 The work function of the Schottky anode is 3.0 eV to 4.2 eV.

[0020] Optionally, the first anode structure includes a second P-type anode region and an anode electrode, wherein the anode electrode is disposed on the surface of the second P-type anode region away from the drift region structure, and the doping concentration of the second P-type anode region is 1×10⁻⁶. 18 cm -3 ~1×10 20cm -3 .

[0021] Optionally, the drift region structure includes an N-type drift layer and an N-type buffer layer. The N-type drift layer is disposed on the surface of the N-type buffer layer facing away from the first anode structure and the second anode structure. The doping concentration of the N-type drift layer is 7.7 × 10⁻⁶. 13 cm -3 ~1×10 15 cm -3 The doping concentration of the N-type buffer layer is 5 × 10⁻⁶. 15 cm -3 ~1×10 17 cm -3 .

[0022] Optionally, the gate structure includes a gate electrode, a gate oxide layer, a polysilicon gate, and a P-type base region. The polysilicon gate extends through the P-type base region. The gate oxide layer is formed on the sidewall of the polysilicon gate. The gate electrode is disposed on the surface of the polysilicon gate away from the drift region structure. The doping concentration of the P-type base region is 8 × 10⁻⁶. 15 cm -3 ~1×10 17 cm -3 The doping concentration of the polysilicon gate is 1×10⁻⁶. 20 cm -3 ~5×10 21 cm -3 The thickness of the gate oxide layer is 0.1 μm to 0.5 μm.

[0023] Optionally, the cathode structure includes a cathode electrode, a P-type cathode region, and an N-type cathode region. The sidewalls of the P-type cathode region are in contact with the sidewalls of the N-type cathode region, and the P-type and N-type cathode regions are located on the same surface. The sidewalls of the N-type cathode region are also in contact with the sidewalls of the gate oxide layer. The cathode electrode is in contact with both the P-type and N-type cathode regions. The doping concentration of the P-type cathode region is 1 × 10⁻⁶. 18 cm -3 ~1×10 20 cm -3 The doping concentration of the N-type cathode region is 1×10⁻⁶. 19 cm -3 ~1×10 20 cm -3 .

[0024] A method for fabricating a reverse-conducting IGBT device, the method being used to fabricate the reverse-conducting IGBT device described in any one of the above-mentioned methods.

[0025] Compared with the prior art, the technical solution provided by this invention has the following advantages:

[0026] By introducing a second anode structure into the first anode structure and utilizing the first PN junction barrier formed by the second anode structure and the drift region structure, the bounce phenomenon of the traditional structure under short cells is eliminated during the forward conduction stage of the device. Furthermore, during reverse conduction, the large number of electrons introduced by the work function difference between the first P-type anode region and the Schottky anode in the second anode structure ensures the reverse conduction capability of the device. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is one of the schematic diagrams of the cell structure of the reverse-conducting IGBT device proposed in Embodiment 1;

[0029] Figure 2 This is the second schematic diagram of the cell structure of the reverse-conducting IGBT device proposed in Embodiment 1.

[0030] Figure 3 This is a schematic diagram of the cell structure of the traditional reverse-conducting IGBT device proposed in Embodiment 1.

[0031] Figure 4 This is a schematic diagram illustrating the working principle of the reverse-conducting IGBT device proposed in Embodiment 1 under three forward conduction voltages;

[0032] Figure 5 This is a line graph showing the change of conduction band energy in the first P-type anode region with forward voltage during forward conduction, as proposed in Embodiment 1.

[0033] Figure 6 This is the energy band diagram of the first P-type anode region when the Schottky anode has different metal work functions during the reverse initial conduction as proposed in Embodiment 1.

[0034] Figure 7 This is a comparison diagram of the forward conduction characteristics of the reverse-conducting IGBT device proposed in this embodiment and the traditional reverse-conducting IGBT device;

[0035] Figure 8 This is a comparison diagram of the reverse conduction characteristics of the reverse-conducting IGBT device proposed in Embodiment 1 and the traditional reverse-conducting IGBT device;

[0036] Figure 9This is a diagram showing the conduction performance of the reverse-conducting IGBT device proposed in Embodiment 1 under different doping concentrations in the first P-type anode region;

[0037] Figure 10 This is a diagram showing the reverse conduction voltage drop of the reverse-conducting IGBT device proposed in this embodiment for different metal work functions;

[0038] Figure 11 This is a schematic diagram of the cell structure of the reverse-conducting IGBT device proposed in Embodiment 2.

[0039] Reference numerals: 1. First P-type anode region; 2. Schottky anode; 3. Second P-type anode region; 4. Anode electrode; 5. N-type drift layer; 6. N-type buffer layer; 7. Gate electrode; 8. Gate oxide layer; 9. Polysilicon gate; 10. P-type base region; 11. Cathode electrode; 12. P-type cathode region; 13. N-type cathode region; 14. First anode structure; 15. Second anode structure; 16. Drift region structure; 17. Gate structure; 18. Cathode structure; 19. N-type anode region. Detailed Implementation

[0040] The present invention will be further described in detail below with reference to the embodiments. The following embodiments are explanations of the present invention, but the present invention is not limited to the following embodiments. Example

[0041] like Figure 1 As shown, a reverse-conducting IGBT device includes a first anode structure 14, a second anode structure 15, a drift region structure 16, a gate structure 17, and a cathode structure 18. The second anode structure 15 and the first anode structure 14 are located on the same surface and are connected through an N-type drift layer 5. The drift region structure 16 is disposed on the first anode structure 14 and the second anode structure 15, forming a first PN junction barrier with the second anode structure 15 and a second PN junction barrier with the first anode structure 14. The gate structure 17 is disposed on the surface of the drift region structure 16 facing away from the first anode structure 14, and the cathode structure 18 is disposed on the gate structure 17.

[0042] The second anode structure 15 is located on one side of the first anode structure 14, and the second anode structure 15 and the first anode structure 14 are located on the same surface and are connected by a lightly doped N-type drift layer 5. Specifically, as shown in the figure... Figure 2 As shown, the second anode structure 15 includes a lightly doped first P-type anode region 1 and a Schottky anode 2. The Schottky anode 2 is disposed on the surface of the first P-type anode region 1 away from the drift region structure 16. The doping concentration of the first P-type anode region 1 is 4 × 10⁻⁶. 15 cm -3 ~6×10 15cm -3 The work function of the Schottky anode 2 is 3.0 eV to 4.2 eV.

[0043] The first anode structure 14 includes a heavily doped second P-type anode region 3 and an anode electrode 4. The anode electrode 4 is disposed on the surface of the second P-type anode region 3 away from the drift region structure 16. To obtain good ohmic contact, the doping concentration of the second P-type anode region 3 is set to 1 × 10⁻⁶. 18 cm -3 ~1×10 20 cm -3 The first P-type anode region 1 and the second P-type anode region 3 are connected by a lightly doped N-type drift layer 5, and the first P-type anode region 1, the second P-type anode region 3, and the N-type drift layer 5 are located on the same surface. The Schottky anode 2 and the anode electrode 4 are not in contact.

[0044] like Figure 3 The diagram shows the structure of a conventional reverse-conducting IGBT device, including an anode structure, a drift region structure 16, a gate structure 17, and a cathode structure 18. Since the anode structure of a conventional reverse-conducting IGBT device includes a heavily doped N-type anode region 19, a heavily doped second P-type anode region 3, and an anode electrode 4, when the length LA of the second P-type anode region 3 is short, the device will have a large rebound voltage, which will adversely affect the parallel operation of the device. Therefore, the length LA of the second P-type anode region 3 needs to be designed to be sufficiently long. However, if the length of the second P-type anode region 3 is too long and no rebound voltage is generated, the device's temperature and dynamic carrier uniformity will become poor, thus affecting the device's robustness. Therefore, compared with the conventional reverse-conducting IGBT device, this embodiment sets up a second anode structure 15 composed of a first P-type anode region 1 and a Schottky anode 2, and connects it to the first anode structure 14 through an N-type drift layer 5, thereby eliminating the rebound phenomenon.

[0045] Furthermore, such as Figure 1 and Figure 2 As shown, the gate structure 17 includes a gate electrode 7, a gate oxide layer 8, a polysilicon gate 9, and a lightly doped P-type base region 10. The polysilicon gate 9 penetrates the P-type base region 10 and is disposed in multiple sets, spaced apart from each other. The gate oxide layer 8 is formed on the sidewall of the polysilicon gate 9, and its thickness is 0.1 μm to 0.5 μm. The gate electrode 7 is disposed on the surface of the polysilicon gate 9 away from the drift region structure 16. To improve conductivity, the doping concentration of the polysilicon gate 9 in this embodiment is set to 1 × 10⁻⁶. 20 cm -3 ~5×10 21 cm -3 The preferred setting is 1×10 20cm -3 In order to set the device threshold voltage within a reasonable range, the doping concentration of the P-type base region 10 is set to 8 × 10⁻⁶. 15 cm -3 ~1×10 17 cm -3 The preferred setting is 1×10 16 cm -3 .

[0046] The cathode structure 18 includes a cathode electrode 11, a heavily doped P-type cathode region 12, and a heavily doped N-type cathode region 13. The sidewalls of the P-type cathode region 12 and the N-type cathode region 13 are in contact with each other, and the P-type cathode region 12 and the N-type cathode region 13 are located on the same surface. The sidewalls of the N-type cathode region 13 are also in contact with the sidewalls of the gate oxide layer 8. The surfaces of the P-type cathode region 12 and the N-type cathode region 13 near the drift region structure 16 are also in contact with the P-type base region 10. The cathode electrode 11 is in contact with both the P-type cathode region 12 and the N-type cathode region 13. To form a good ohmic contact electrode, the doping concentration of the P-type cathode region 12 is set to 1×10⁻⁶. 18 cm -3 ~1×10 20 cm -3 The preferred setting is 1×10 20 cm -3 The doping concentration of the N-type cathode region 13 is set to 1×10⁻⁶. 19 cm -3 ~1×10 20 cm -3 The preferred setting is 1×10 20 cm -3 .

[0047] The drift region structure 16 includes a lightly doped N-type drift layer 5 and a lightly doped N-type buffer layer 6. The N-type drift layer 5 is disposed on the surface of the N-type buffer layer 6 away from the first anode structure 14 and the second anode structure 15, and the surface of the N-type drift layer 5 away from the N-type buffer layer 6 is in contact with the P-type base region 10 and the gate oxide layer 8. In order to maintain the breakdown voltage of the device, the doping concentration of the N-type drift layer 5 is set to 7.7 × 10⁻⁶. 13 cm -3 ~1×10 15 cm -3 The preferred setting is 1×10 14 cm -3 The doping concentration of the N-type buffer layer 6 is 5 × 10⁶. 15 cm -3 ~1×10 17 cm -3 The preferred setting is 1×10 16 cm -3 .

[0048] Specifically, in this embodiment, in order to eliminate the bounce phenomenon and maintain the reverse conduction capability of the device, a second anode structure 15 is introduced into the first anode structure 14, that is, a Schottky anode 2 and a first P-type anode region 1 are introduced. Through the Schottky anode 2 and the first P-type anode region 1, the first PN junction barrier formed by the N-type buffer layer 6 in the first P-type anode region 1 is utilized to eliminate the bounce phenomenon of the traditional structure under short cells during the forward conduction stage of the device. Furthermore, during reverse conduction, the large number of electrons introduced by the work function difference between the first P-type anode region 1 and the Schottky anode 2 conduct electricity, thus ensuring the reverse conduction capability of the device.

[0049] More specifically, such as Figure 4 As shown, the operation of the novel reverse-conducting IGBT device is divided into three stages: the initial forward conduction stage, the low-voltage forward conduction stage, and the high-voltage forward conduction stage. When in the initial forward conduction stage, as... Figure 3 As shown in (a), due to the effect of the first PN junction barrier formed by the first P-type anode region 1 and the N-type buffer layer 6, the electron flow path is blocked. At this time, the current is small, the flow path resistance is large, and the device is in unipolar operation mode. As the forward voltage increases, when in the low-voltage forward conduction stage, as... Figure 3 As shown in (b), the barrier of the first PN junction gradually decreases. At this time, the current increases and the resistance decreases, but the resistance value is still relatively large, and the unipolar operating mode of the device is weakened. As the forward voltage further increases, when in the high-voltage forward conduction stage, as... Figure 3 As shown in (c), the second PN junction barrier formed by the second P-type anode region 3 and the N-type buffer layer 6 is turned on, and a large number of holes are injected into the N-type drift layer 5. Due to the conductivity modulation effect, the resistance of the drift region decreases, and the device enters the bipolar working mode.

[0050] Although the forward voltage causes the first P-type anode region 1 to punch through, allowing some electrons to flow through it and weakening its electron blocking ability, the first P-type anode region 1 maintains a relatively large resistance before the bipolar operating mode. This allows the forward voltage to be applied simultaneously to the PN junction formed by the second P-type anode region 3 and the N-type buffer layer 6, causing the PN junction to conduct and eliminating the bounce phenomenon. This solves the current misalignment problem caused by the bounce phenomenon, while also reducing the turn-off time of the IGBT section and the reverse recovery time of the diode section, as well as reducing the overall power switching loss of the device.

[0051] On the other hand, during reverse conduction, due to the low work function of the Schottky anode 2, an inversion layer appears on the lower surface of the first P-type anode region 1. As the reverse voltage increases, the barrier of the first P-type anode region 1 is broken through, and the device begins to conduct electricity. Furthermore, since the energy difference between the conduction bands of the metal and the semiconductor is small, electrons can enter the semiconductor from the metal under the action of the reverse voltage, maintaining conduction and thus ensuring the reverse conduction capability of the device.

[0052] To further verify the performance of the novel reverse-conducting IGBT device in this embodiment, this embodiment takes a 1200V novel reverse-conducting IGBT as an example and compares its performance with that of a traditional reverse-conducting IGBT through simulation.

[0053] like Figure 5 The figure shows a line graph illustrating the change in conduction band energy of the first P-type anode region 1 with forward voltage when the novel reverse-conducting IGBT device of this embodiment is in forward conduction. As can be seen from the figure, when V... CE When the voltage is 0V, the potential barrier of the first P-type anode region 1 is relatively large. Electrons flowing from the N-type buffer layer 6 to the Schottky anode 2 need to pass through the high potential barrier region (i.e., the first PN junction barrier) formed by the first P-type anode region 1. At this time, due to the blocking effect of the potential barrier region, the number of electrons that can cross the barrier is small, so the electron current is small and the resistance is large.

[0054] With V CE When the voltage is increased to 0.7V, the potential barrier of the first P-type anode region 1 decreases, but is still relatively large, resulting in a larger resistance value. This weakens the unipolar operating mode of the device, allowing the forward voltage to be applied simultaneously to the PN junction formed by the second P-type anode region 3 and the N-type buffer layer 6, thus promoting the device to enter the bipolar operating mode.

[0055] When VCE is 1.7V, the device enters the bipolar operating mode. At this time, the potential barrier of the first P-type anode region 1 is almost completely weakened, and its ability to block electrons is small. However, since the first P-type anode region 1 always maintains a large resistance in the unipolar operating mode of the device, the bounce phenomenon of the device is eliminated.

[0056] During reverse conduction, due to the influence of the work function of the Schottky anode 2, the conduction band of the first P-type anode region 1 near the upper surface of the Schottky anode 2 will approach the Fermi level. At this time, electrons in the metal will enter the semiconductor and participate in conduction in large quantities, thus ensuring the reverse conduction capability of the device.

[0057] Specifically, such as Figure 6The diagram shows the band structure of the first P-type anode region 1 when the Schottky anode 2 has different metal work functions during the initial conduction of the novel reverse-conducting IGBT device of this embodiment. When the metal work function is 4.4 eV, the conduction band is far from the Fermi level at a length of 120 μm. The lower surface of the first P-type anode region 1 exhibits a weak inversion region. Since the electron concentration on this surface is low at this time, and it is difficult for electrons to enter the semiconductor from the metal, the device cannot conduct.

[0058] At a metal work function of 4.2 eV, although the conduction band and Fermi level are relatively close, electrons still cannot enter the semiconductor under low reverse voltage, and the device cannot conduct in reverse.

[0059] When the work function of the metal is 4.0 eV, the conduction band is below the Fermi level, the lower surface of the first P-type anode region 1 enters a strong inversion state, and electrons can enter the semiconductor at a very small voltage. At this time, the device can maintain good reverse conduction performance, thus verifying the above statement.

[0060] like Figure 7 The figure shown is a comparison of the forward conduction characteristics of the novel reverse-conducting IGBT device and the traditional reverse-conducting IGBT device in this embodiment. The novel reverse-conducting IGBT device in this embodiment successfully eliminates the bounce phenomenon of the short-cell reverse-conducting IGBT device, while the traditional type still cannot completely eliminate the bounce phenomenon under the condition of LA of 100μm.

[0061] At 150A / cm 2 At the given on-current density, the on-voltage drop of the novel reverse-conducting IGBT device in this embodiment is 1.41V, which is slightly higher than the 1.37V of the traditional reverse-conducting IGBT device, but eliminates the harmful bounce phenomenon in parallel operation.

[0062] like Figure 8 The figure shows a comparison of the reverse conduction characteristics of the novel reverse-conducting IGBT device and the conventional reverse-conducting IGBT device in this embodiment. As can be seen from the figure, at a reverse conduction current density of 150A / cm2, the reverse conduction voltage drop of the novel reverse-conducting IGBT device in this embodiment is 1.25V, which is only slightly higher than the conventional type of 1.21V. This is due to the combined effect of the barrier between the first P-type anode region 1 and the Schottky anode 2.

[0063] like Figure 9 The diagram shows the conduction performance of the novel reverse-conducting IGBT device in this embodiment under different doping concentrations in the first P-type anode region 1. Since the novel reverse-conducting IGBT device in this embodiment requires no backflow during forward conduction and conduction in reverse, therefore... Figure 9 As can be seen from this, the doping concentration of the first P-type anode region 1 needs to be controlled at 4 × 10⁻⁶. 15 cm-3 ~6×10 15 cm -3 Within the range.

[0064] like Figure 10 The figure shows the reverse conduction voltage drop of the novel reverse-conducting IGBT device in this embodiment under different metal work functions. As can be seen from the figure, in order to obtain a smaller reverse conduction voltage drop and considering the availability of the metal work function, it is necessary to control the metal work function between 3.0 eV and 4.2 eV. Example

[0065] like Figure 11 As shown, the difference between this embodiment and Embodiment 1 is that, in this embodiment, a second anode structure 15 is provided on both sides of the first anode structure 14, and the second anode structures 15 on both sides are located on the same surface as the first anode structure 14 and are connected by an N-type drift layer 5. By introducing a Schottky anode 2 and a first P-type anode region 1, and utilizing the first PN junction barrier formed by the N-type buffer layer 6 in the first P-type anode region 1, the bounce phenomenon of the traditional structure under short cells is eliminated during the forward conduction stage of the device. Furthermore, by utilizing the large number of electrons introduced by the work function difference between the first P-type anode region 1 and the Schottky anode 2 during reverse conduction, the reverse conduction capability of the device is guaranteed. At the same time, the provision of the second anode structures 15 on both sides makes the carrier distribution more uniform. Example

[0066] A method for fabricating a reverse-conducting IGBT device, the method being used to fabricate the reverse-conducting IGBT device of either Example 1 or Example 2.

[0067] The steps for preparing the novel reverse-conducting IGBT device shown in Example 1 are as follows:

[0068] S1, Select a doping concentration of 7.7 × 10⁻⁶ 13 cm -3 ~1×10 15 cm -3 Using an N-type silicon wafer as the substrate, a lightly doped N-type drift layer 5 with a thickness of 100μm~150μm was obtained;

[0069] S2. Etch the silicon substrate to form trenches of 4μm~8μm;

[0070] S3 and O2 annealing form a SiO2 layer with a thickness of 0.1μm~0.5μm, forming the gate oxide layer 8;

[0071] S4. Polysilicon gate 9 is formed by depositing polysilicon on the surface of the SiO2 trench with a concentration of 1×10⁻⁶. 20 cm -3 ~5×10 21 cm-3 ;

[0072] S5, P-type cathode region 12 heavily doped with boron ions implanted onto the substrate surface, with a dose of 1×10⁻⁶. 18 cm -3 ~1×10 20 cm -3 ;

[0073] S6. Boron ions are implanted into the substrate surface to form a lightly doped P-type base region 10, with a dose of 8 × 10⁻⁶. 15 cm -3 ~1×10 17 cm -3 ;

[0074] S7. Phosphorus ions are implanted into the substrate surface to form a heavily doped N-type cathode region 13, with a dose of 1×10⁻⁶. 19 cm -3 ~1×10 20 cm -3 ;

[0075] S8. Phosphorus ions are implanted on the back side of the substrate to form a lightly doped N-type buffer layer 6, with a dose of 5 × 10⁻⁶. 15 cm -3 ~1×10 17 cm -3 ;

[0076] S9. Boron ions are implanted on the back side of the substrate to form a heavily doped second P-type anode region 3 on one side of the back side of the substrate, with a dose of 1×10⁻⁶. 18 cm -3 ~1×10 20 cm -3 ;

[0077] S10. Boron ions are implanted on the back side of the substrate to form a lightly doped first P-type anode region 1 on the other side of the back side of the substrate, with a dose of 4 × 10⁻⁶. 15 cm -3 ~6×10 15 cm -3 ;

[0078] S11. Double-sided aluminum evaporation forms an ohmic contact electrode, forming a cathode electrode 11, a gate electrode 7, and an anode electrode 4.

[0079] S12. Select a metal with a work function of 3.0 eV to 4.2 eV to form a P-type Schottky anode 2.

[0080] The steps for preparing the reverse-conducting IGBT device shown in Example 2 are as follows:

[0081] S1, Select a doping concentration of 7.7 × 10⁻⁶ 13 cm-3 ~1×10 15 cm -3 Using an N-type silicon wafer as the substrate, a lightly doped N-type drift layer 5 with a thickness of 100μm~150μm was obtained;

[0082] S2. Etch the silicon substrate to form trenches of 4μm~8μm;

[0083] S3 and O2 annealing form a SiO2 layer with a thickness of 0.1μm~0.5μm, forming the gate oxide layer 8;

[0084] S4. Polysilicon gate 9 is formed by depositing polysilicon on the surface of the SiO2 trench with a concentration of 1×10⁻⁶. 20 cm -3 ~5×10 21 cm -3 ;

[0085] S5, P-type cathode region 12 heavily doped with boron ions implanted onto the substrate surface, with a dose of 1×10⁻⁶. 18 cm -3 ~1×10 20 cm -3 ;

[0086] S6. Boron ions are implanted into the substrate surface to form a lightly doped P-type base region 10, with a dose of 8 × 10⁻⁶. 15 cm -3 ~1×10 17 cm -3 ;

[0087] S7. Phosphorus ions are implanted into the substrate surface to form a heavily doped N-type cathode region 13, with a dose of 1×10⁻⁶. 19 cm -3 ~1×10 20 cm -3 ;

[0088] S8. Phosphorus ions are implanted on the back side of the substrate to form a lightly doped N-type buffer layer 6, with a dose of 5 × 10⁻⁶. 15 cm -3 ~1×10 17 cm -3 ;

[0089] S9. Boron ions are implanted on the back side of the substrate to form heavily doped second P-type anode regions 3 on both sides of the back side of the substrate, with a dose of 1×10⁻⁶. 18 cm -3 ~1×10 20 cm -3 ;

[0090] S10. Boron ions are implanted on the back side of the substrate to form a lightly doped first P-type anode region 1 between the two sets of second P-type anode regions 3 on the back side of the substrate, with a dose of 4 × 10⁻⁶. 15 cm -3 ~6×10 15 cm -3 ;

[0091] S11. Double-sided aluminum evaporation forms an ohmic contact electrode, forming a cathode electrode 11, a gate electrode 7, and an anode electrode 4.

[0092] S12. Select a metal with a work function of 3.0 eV to 4.2 eV to form a P-type Schottky anode 2.

[0093] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any form or substance. It should be noted that those skilled in the art can make various improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention. Any modifications, alterations, and equivalent changes made by those skilled in the art based on the above-disclosed technical content without departing from the spirit and scope of the present invention are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, and evolutions made to the above embodiments based on the essential technology of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A reverse-conducting IGBT device, characterized in that, include: A first anode structure, comprising a second P-type anode region and an anode electrode, wherein the anode electrode is disposed on the surface of the second P-type anode region away from the drift region structure; The second anode structure is located on the same surface as the first anode structure and is connected to the first anode structure through an N-type drift layer. The second anode structure includes a first P-type anode region and a Schottky anode, wherein the Schottky anode is disposed on the surface of the first P-type anode region away from the drift region structure. A drift region structure is disposed on a first anode structure and a second anode structure. The drift region structure and the second anode structure form a first PN junction barrier, and the drift region structure and the first anode structure form a second PN junction barrier. A gate structure, wherein the gate structure is disposed on the surface of the drift region structure opposite to the first anode structure; A cathode structure is disposed on a gate structure.

2. The reverse-conducting IGBT device according to claim 1, characterized in that, When in the initial forward conduction phase, the first PN junction barrier blocks the electron flow path, and the device operates in unipolar mode. When in the low-voltage forward conduction stage, the barrier of the first PN junction decreases, and the unipolar operating mode of the device is weakened. When in the high-voltage forward conduction stage, the second PN junction barrier is turned on, and the device enters the bipolar operating mode.

3. The reverse-conducting IGBT device according to claim 1, characterized in that, The second anode structure is located on one side of the first anode structure; Alternatively, the second anode structure is located on both sides of the first anode structure, with one or both sides of the second anode structure located on the same surface as the first anode structure and connected by an N-type drift layer.

4. A reverse-conducting IGBT device according to any one of claims 1-3, characterized in that, The doping concentration of the first P-type anode region is 4 × 10⁻⁶. 15 cm -3 ~6×10 15 cm -3 The work function of the Schottky anode is 3.0 eV to 4.2 eV.

5. A reverse-conducting IGBT device according to claim 1, characterized in that, The doping concentration of the second P-type anode region is 1×10⁻⁶. 18 cm -3 ~1×10 20 cm -3 .

6. A reverse-conducting IGBT device according to claim 1, characterized in that, The drift region structure includes an N-type drift layer and an N-type buffer layer. The N-type drift layer is disposed on the surface of the N-type buffer layer facing away from the first anode structure and the second anode structure. The doping concentration of the N-type drift layer is 7.7 × 10⁻⁶. 13 cm -3 ~1×10 15 cm -3 The doping concentration of the N-type buffer layer is 5 × 10⁻⁶. 15 cm -3 ~1×10 17 cm -3 .

7. A reverse-conducting IGBT device according to claim 1, characterized in that, The gate structure includes a gate electrode, a gate oxide layer, a polysilicon gate, and a P-type base region. The polysilicon gate extends through the P-type base region. The gate oxide layer is formed on the sidewall of the polysilicon gate. The gate electrode is disposed on the surface of the polysilicon gate away from the drift region structure. The doping concentration of the P-type base region is 8 × 10⁻⁶. 15 cm -3 ~1×10 17 cm -3 The doping concentration of the polysilicon gate is 1×10⁻⁶. 20 cm -3 ~5×10 21 cm -3 The thickness of the gate oxide layer is 0.1 μm to 0.5 μm.

8. A reverse-conducting IGBT device according to claim 7, characterized in that, The cathode structure includes a cathode electrode, a P-type cathode region, and an N-type cathode region. The sidewalls of the P-type cathode region are in contact with the sidewalls of the N-type cathode region, and the P-type and N-type cathode regions are located on the same surface. The sidewall of the N-type cathode region is also in contact with the sidewall of the gate oxide layer. The cathode electrode is in contact with both the P-type and N-type cathode regions. The doping concentration of the P-type cathode region is 1 × 10⁻⁶. 18 cm -3 ~1×10 20 cm -3 The doping concentration of the N-type cathode region is 1×10⁻⁶. 19 cm -3 ~1×10 20 cm -3 .

9. A method for fabricating a reverse-conducting IGBT device, characterized in that, The preparation method is used to prepare the reverse-conducting IGBT device according to any one of claims 1-8.

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