An independently designable FWD RC-LIGBT device

Abstract

The application relates to an RC-LIGBT device with independently designed FWD, and belongs to the technical field of power semiconductors. The RC-LIGBT device comprises an LIGBT region and a reverse freewheeling region, the reverse freewheeling region comprises a reverse freewheeling part which can be independently installed in the region, and the reverse freewheeling part is configured as a pin diode freewheeling part, an MPS freewheeling part or a MOS Channel Diode freewheeling part. The LIGBT device of the application fundamentally suppresses the generation of negative resistance effect when the LIGBT device is forwardly turned on without the collector region N+ part of the traditional RC-LIGBT, and has no latch-up effect; and when the LIGBT device is reversely turned on, the independently designed freewheeling diode part is turned on when VEC>Vth, thereby providing reverse current during the period; and the reverse conduction part of the IGBT can be independently designed to obtain different reverse performances and characteristics without affecting the forward performance of the device.

Description

Technical Field

[0001] This invention belongs to the field of power semiconductor devices and relates to an RC-LIGBT device with independently designable FWD. Background Technology

[0002] The rapid development of industries such as new energy, high-speed rail, electric vehicles, and smart grids makes insulated-gate bipolar transistors (IGBTs) indispensable. IGBTs are a new type of composite power device developed based on metal-oxide-semiconductor field-effect transistors (MOSFETs) and bipolar junction transistors (BJTs), combining the advantages of both. Among them, LIGBTs (Lateral Insulated-Gate Bipolar Transistors) are easily integrated onto silicon-based substrates and are commonly used in SOI-based power intelligent systems, representing a typical example of bipolar semiconductor devices.

[0003] However, since LIGBTs lack reverse conduction capability, an additional freewheeling diode is needed to achieve reverse conduction and suppress the additional voltage generated by parasitic inductance in the circuit. Meanwhile, to improve device integration and reduce manufacturing costs, researchers began to integrate the protective freewheeling diode inside the LIGBT, creating an RC-LIGBT (Reverse-Conducting Lateral Insulated Gate Bipolar Transistor). This not only provides bidirectional conduction capability but also significantly improves chip integration. Furthermore, the additional interconnect between the insulated gate bipolar transistor and the freewheeling diode solves the reliability issues between chips.

[0004] However, traditional reverse-conducting insulated-gate transistors (RC-LIGBTs) have a new drawback: during forward conduction, electrons first pass through the N-Collector. Only when the current density is large enough can holes be injected into the drift region from the collector P+ region. This involves a transition from a single-electron conduction mode to a bipolar conduction mode, resulting in a negative resistance effect on the current-voltage output curve. Furthermore, the introduction of N+ in the collector region of traditional RC-LIGBTs can affect the breakdown performance of the device.

[0005] For example, prior art disclosed in Publication No. CN 106057876B discloses an IGBT with reverse freewheeling capability, including: a front-side MOS structure, an N-type drift region, and a back-side collector structure; the back-side collector structure includes an N+ buffer layer, a P+ injection layer, and a back-side metal layer. The pattern structure of the P+ injection layer is defined by a groove formed on the front side of the semiconductor substrate, the junction depth of the N+ buffer layer is greater than the depth of the groove, the P+ injection layer is less than the depth of the groove and is located on the back side of the N+ buffer layer of the semiconductor substrate between the grooves; the back-side metal layer completely fills the groove and extends to the entire back side of the semiconductor substrate outside the groove.

[0006] In this prior art, electrons first pass through the N-Collector during forward conduction. Only when the current density is sufficiently high can holes be injected into the drift region from the collector P+ region. This involves a transition from a single-electron conduction mode to a bipolar conduction mode, resulting in a negative resistance effect on the current-voltage output curve and affecting the forward conduction of the device. Secondly, the introduction of N+ ions into the collector region in this prior art affects the breakdown performance of the device. Finally, the reverse freewheeling performance of this prior art is usually fixed, and its reverse conduction performance cannot be adjusted according to requirements after fabrication.

[0007] Therefore, in order to better promote the application of LIGBTs, further improvements are needed to optimize various performance characteristics of LIGBTs and thus enhance the reliability of LIGBT devices. Summary of the Invention

[0008] In view of this, the purpose of the present invention is to provide an RC-LIGBT device that can be independently designed as a FWD (Freewheeling diode). In the structure of a traditional IGBT device, the device is turned on and off by using a cathode MOS; an independent reverse conduction section is used to provide reverse current to the device when it is reverse conducting. By changing the reverse conduction section, RC-LIGBTs with different reverse performance can be obtained without sacrificing the forward performance of the LIGBT.

[0009] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0010] An RC-LIGBT device with independently designable FWD, the RC-LIGBT device includes a LIGBT region and a reverse freewheeling region, the reverse freewheeling region includes a reverse freewheeling section that can be independently mounted in the region, the reverse freewheeling section being configured as a pin diode freewheeling section, an MPS freewheeling section or a MOS Channel Diode freewheeling section.

[0011] Furthermore, the freewheeling portion of the pin diode includes, from left to right, the N+ region of the pin diode cathode, the drift region of the pin diode, the P+ region of the pin diode anode, the pin cathode, and the pin anode. The freewheeling portion of the pin diode is separated from the IGBT region by an oxide isolation layer. The left side of the pin diode cathode is tightly connected to the oxide isolation layer. The P+ region of the pin diode anode is located at the upper right end of the device. The pin anode is shorted to the emitter of the IGBT region, and the pin cathode is shorted to the collector of the IGBT region. When the RC-LIGBT device enters the reverse operating state, the diode conducts after the voltage drop between the emitter and collector exceeds the pin threshold voltage, thus realizing the reverse conduction function of the RC-LIGBT.

[0012] Furthermore, the MPS freewheeling section includes, from left to right, a cathode N+ region, an MPS drift region, an ohmic contact P+ region, a Schottky contact, an anode, and a cathode. The MPS section is separated from the IGBT region by an oxide isolation layer. The left side of the cathode N+ region is tightly connected to the oxide isolation layer. The ohmic contact P+ region and the Schottky contact are connected to the anode and are located at the upper right of the entire device. The MPS anode is shorted to the emitter of the IGBT region, and the MPS cathode is shorted to the collector of the IGBT region. When the RC-LIGBT device enters the reverse operating state, the diode conducts when the voltage drop between the emitter and collector exceeds the MPS threshold voltage, thus realizing the reverse conduction function of the RC-LIGBT.

[0013] Furthermore, the freewheeling section of the MOS Channel Diode includes, from left to right, the cathode N+ region, the MOS Channel Diode drift region, the MOS Channel Diode P-base region, the MOS Channel Diode anode N+ region, the MOS Channel Diode anode P+ region, the MOS Channel Diode gate oxide layer, the MOS Channel Diode anode, and the MOS Channel Diode cathode. The anode P+ and anode N+ regions of the MOS Channel Diode are closely connected and enclosed by the MOS Channel Diode P-base region. The left side of the MOS Channel Diode cathode N+ region is closely connected to the oxide isolation layer. The gate oxide layer is connected to the upper side of the MOS Channel Diode P-base region, the MOS Channel Diode drift region, and the MOS Channel Diode anode N+ region; the MOS Channel Diode gate oxide layer is shorted to the MOS Channel Diode anode. When the RC-LIGBT device is in reverse operation, a positive voltage is applied to the anode. Because the gate and anode are shorted, when the applied voltage exceeds the threshold voltage, the electron channel of the MOS Channel Diode is turned on, and the MOS Channel Diode provides freewheeling.

[0014] Furthermore, the LIGBT region includes a P+ emitter, an N+ electron emitter, a P-base, an N-type drift region, a silicon dioxide insulating layer, a P-type substrate, an N-type buffer layer, a P+ collector, a collector, a gate, and an emitter.

[0015] Furthermore, the LIGBT region is configured as follows, from left to right: P+ emitter, N+ electron emitter, P-base, N-type drift region, silicon dioxide insulating layer, P-type substrate, N-type buffer layer, P+ collector, collector, gate, and emitter. The P+ emitter is located below the emitter, its left side is flush with the left side of the device, its right side is closely connected to the left side of the N+ electron emitter, and its bottom side is connected to the P-base. The N+ electron emitter is located below the emitter and gate, and its right and bottom sides are completely covered by the P-base. The top side of the P-base is flush with the top sides of the P+ emitter and N+ electron emitter, and its right and bottom sides are completely covered by the N-type drift region. The top side of the N-type drift region is flush with the top sides of the P+ emitter, N+ electron emitter, gate, N-type buffer layer, and P+ collector, its bottom side is closely connected to the top side of the silicon dioxide insulating layer, its left side is flush with the left side of the device, and its right side is flush with the right side of the device. The upper side of the N-type buffer layer is flush with the upper side of the device, the right side is flush with the right side of the oxide isolation layer, and the left and lower sides are completely covered by the N-type drift region. The P+ collector is located below the collector, its upper side is flush with the upper side of the device, its right side is flush with the oxide isolation layer, and its left and lower sides are completely covered by the N-type buffer layer (7). The gate (17) is made of doped polysilicon or aluminum.

[0016] The beneficial effects of this invention are as follows:

[0017] (1) When the device is forward-biased, there is no negative resistance effect. When the device is forward-biased, the negative resistance effect is fundamentally suppressed because there is no N+ portion of the collector region of the traditional RC-LIGBT, and there is no latch-up effect.

[0018] (2) During reverse conduction, when V EC >V th When this occurs, the independently designed freewheeling diode partially turns on, providing reverse current during this period.

[0019] (3) The reverse conduction section of this IGBT can be designed independently to obtain different reverse performance and characteristics without affecting the forward performance of the device.

[0020] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0021] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0022] Figure 1Figure (a) is a schematic diagram of the structure of an RC-LIGBT device with a pin diode as the reverse part according to Embodiment 1 of the present invention, and Figure (b) is a cross-sectional view of AA' in Figure (a);

[0023] Figure 2 for Figure 1 Equivalent circuit diagram of the structure;

[0024] Figure 3 Figure (a) is a schematic diagram of the structure of an RC-LIGBT device with an MPS diode as the reverse part according to Embodiment 2 of the present invention; Figure (b) is the CC' section of Figure (a); and Figure (c) is the BB' section of Figure (a).

[0025] Figure 4 for Figure 3 Equivalent circuit diagram of the structure;

[0026] Figure 5 Figure (a) is a schematic diagram of the structure of an RC-LIGBT device with a reverse portion being a MOS Channel Diode according to Embodiment 3 of the present invention, and Figure (b) is a cross-section of DD' in Figure (a);

[0027] Figure 6 for Figure 5 Equivalent circuit diagram of the structure;

[0028] Figure 7 The conduction curves of Example 1 are compared with those of a conventional RC-LIGBT and a conventional LIGBT.

[0029] Figure 8 A comparison of the breakdown curves of Example 1 and a conventional LIGBT device;

[0030] Figure 9 A comparison of the turn-off curves of Example 1 and a conventional LIGBT device;

[0031] Figure 10 This is a comparison of the reverse conduction performance of Example 1 with that of a conventional RC-LIGBT;

[0032] Figure 11 This is a comparison of the conduction curves of Example 2 with those of a conventional RC-LIGBT and a conventional LIGBT;

[0033] Figure 12 A comparison of the breakdown curves of Example 2 and a conventional LIGBT;

[0034] Figure 13 Example 2 shows a comparison of the turn-off curves with those of a conventional LIGBT;

[0035] Figure 14The reverse conduction performance of Example 2 is compared with that of a conventional RC-LIGBT and Example 1;

[0036] Figure 15 This is a comparison of the reverse recovery performance between Example 2 and Example 1;

[0037] Figure 16 The conduction curves of Example 3 are compared with those of a conventional RC-LIGBT and a conventional LIGBT.

[0038] Figure 17 The breakdown curves of Example 3 are compared with those of a conventional LIGBT device;

[0039] Figure 18 Example 3 shows a comparison of the turn-off curves with those of a conventional LIGBT;

[0040] Figure 19 This is a comparison of the reverse recovery performance of Example 3 and Example 1.

[0041] Figure reference numerals: 1-P+ emitter, 2-N+ electron emitter, 3-P-base, 4-N-type drift region, 5-silicon dioxide insulating layer, 6-P-type substrate, 7-N-type buffer layer, 8-P+ collector, 9-collector, 10-oxide isolation layer, 11-cathode, 12-anode, 13-anode P+ region, 14-drift region, 15-cathode N+ region, 16-emitter, 17-gate, 18a-Schottky contact, 18b-MOS Channel Diode P-base region, 19-gate oxide layer, 20-MOS Channel Diode anode N+ region. Detailed Implementation

[0042] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0043] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0044] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0045] Please see Figures 1 to 19 It is an RC-LIGBT device that allows for independent design of FWD (Freewheeling diode).

[0046] Example 1:

[0047] like Figure 1 As shown in the figure, the present invention proposes an RC-LIGBT device with an independent pin diode for the reverse freewheeling section. Its main structural feature is that the device is divided into a LIGBT region and a reverse conduction pin region from left to right, separated by an oxide isolation layer 10. The LIGBT region includes a P+ emitter 1, an N+ electron emitter 2, a P-base 3, an N-type drift region 4, a silicon dioxide insulating layer 5, a P-type substrate 6, an N-type buffer layer 7, a P+ collector 8, a collector 9, a gate 17, and an emitter 16, wherein the P+... The right side of P+ emitter 1 is closely connected to the left side of N+ electron emitter 2. Their upper sides are flush with the upper side of the device and located in the upper left of the entire device. The lower end of P+ emitter 1, the lower end of N+ electron emitter 2 and the right end are wrapped by P-base 3. The right end and the lower end of P-base 3 are closely connected to N-type drift region 4. The right side of P+ collector is closely connected to oxide isolation layer 10. Its upper end is flush with the upper side of the device. Its left and lower sides are completely wrapped by N-type buffer layer 7. The left and lower sides of N-type buffer layer 7 are closely connected to N-type drift region 4.

[0048] The reverse-conduction pin section, from left to right, comprises the pin diode's cathode N+ region 15, drift region 14, anode P+ region 13, cathode 11, and anode 12. The pin diode's freewheeling portion is separated from the IGBT region by an oxide isolation layer 10. The left side of the pin diode's cathode portion is tightly connected to the oxide isolation layer 10. The pin diode's anode P+ region 13 is located at the upper right end of the device. The pin anode 12 is shorted to the IGBT region's emitter 16, and the pin cathode 11 is shorted to the IGBT region's collector 9. When the entire device enters the reverse operating state, the diode conducts when the voltage drop between the emitter 16 and collector 9 exceeds the pin threshold voltage, thus realizing the reverse conduction function of the RC-LIGBT.

[0049] When the device is forward-biased, the new structure operates in the same manner as a conventional IGBT. The gate voltage of the cathode MOS gradually increases, opening the electron channel and allowing electrons to be injected into the drift region from the emitter. When enough electrons accumulate below the N-type buffer layer, the IGBT's PNP transistor turns on and injects holes into the drift region, thus entering a bipolar operating mode. The reverse pin diode is off at this time. Because there is no anode N+ region like in a traditional RC-LIGBT, the PNP transistor can turn on early, allowing the device to enter bipolar operating mode. This structure avoids negative resistance during forward conduction and eliminates voltage foldback. In reverse conduction, as the cathode voltage increases, the reverse pin portion turns on, providing a bipolar reverse current and resulting in a superior reverse conduction threshold voltage.

[0050] Using SENTAURUS simulation software, the LIGBT device in the proposed implementation case 1 was simulated as follows: Figure 1 The structure shown was subjected to performance simulation analysis to analyze its mechanism and electrical simulation. During the simulation, all simulation parameters of the device in Example 1 were consistent with those of the conventional device, with a carrier lifetime of 10 μs and an ambient temperature of 300 K.

[0051] Figure 2 The diagram shown is the equivalent circuit diagram of the RC-LIGBT device in Example 1, where the IGBT is equivalent to an NMOS-controlled PNP transistor; the reverse freewheeling PIN diode is connected in parallel with the collector and emitter of the PNP transistor to provide reverse current to the device.

[0052] Figure 7 This is a comparison of the conduction curves for Example 1 when the drift region length is 30 μm. Example 1 had a drift region concentration of 1.5 × 10⁻⁶. 15 cm -3The forward conduction voltage is 1.31V, and its forward conduction performance is basically the same as that of a traditional LIGBT. However, due to some leakage current in the reverse part, the forward conduction voltage is slightly larger. Compared with the traditional RC-LIGBT, it can be seen that this structure of RC-LIGBT avoids the negative resistance effect of the traditional RC-LIGBT and improves the reliability of the device.

[0053] Figure 8 Comparing the breakdown voltage performance of the structure in Example 1 with that of a conventional LIGBT device, the breakdown voltage of the device structure in Example 1 is 279.2V. Since Example 1 is an RC-LIGBT, there will be a small amount of leakage current, resulting in a breakdown voltage that is slightly lower than that of the conventional structure. However, overall, its reverse freewheeling region does not affect its breakdown voltage performance.

[0054] Figure 9 The comparison of the turn-off performance of Example 1 with that of a conventional LIGBT shows that the device performance was not affected by the addition of the reverse function. Furthermore, based on the above simulation of the forward performance, it can be seen that the structure of Example 1 eliminates the negative resistance effect of the conventional RC-LIGBT device without affecting the forward performance, thus improving the reliability of the device.

[0055] Figure 10 Comparing the reverse conduction performance of Example 1 with that of a traditional RC-LIGBT, it can be seen that the reverse conduction performance of Example 1 is far superior to that of the traditional RC-LIGBT. This is because the reverse current in Example 1 is provided by the PIN diode during reverse conduction. Since the PIN diode operates in bipolar mode when conducting, the reverse conduction voltage drop is reduced. Compared to the traditional RC-LIGBT, it has no negative resistance effect and its reverse conduction capability is also stronger.

[0056] In summary, Example 1 eliminates the negative resistance effect of traditional RC-LIGBT devices without affecting the forward performance, and its reverse conduction is superior to that of traditional RC-LIGBTs.

[0057] Example 2:

[0058] like Figure 3As shown in the figure, the present invention proposes an RC-LIGBT device with an independent MPS diode for the reverse freewheeling section. Its main structural feature is that the device is divided into a LIGBT region and a reverse-conducting MPS region from left to right, separated by an oxide isolation layer 10. The LIGBT region includes a P+ emitter 1, an N+ electron emitter 2, a P-base 3, an N-type drift region 4, a silicon dioxide insulating layer 5, a P-type substrate 6, an N-type buffer layer 7, a P+ collector 8, a collector 9, a gate 17, and an emitter 16, wherein the P... The right side of P+ emitter 1 is closely connected to the left side of N+ electron emitter 2. Their upper sides are flush with the upper side of the device and located in the upper left of the entire device. The lower end of P+ emitter 1, the lower end of N+ electron emitter 2 and the right end are wrapped by P-base 3. The right end and the lower end of P-base 3 are closely connected to N-type drift region 4. The right side of P+ collector is closely connected to oxide isolation layer 10. Its upper end is flush with the upper side of the device. Its left and lower sides are completely wrapped by N-type buffer layer 7. The left and lower sides of N-type buffer layer 7 are closely connected to N-type drift region 4.

[0059] The reverse portion is the reverse region of the MPS (Merged PIN / Schottky Semiconductor) RC-LIGBT: from left to right, it comprises a cathode N+ region 15, an MPS drift region 14, an ohmic contact P+ region 13, a Schottky contact portion 18a, an anode 12, and a cathode 11. The MPS portion is separated from the IGBT region by an oxide isolation layer 10. The left side of the cathode N+ region is tightly connected to the oxide isolation layer 10. The ohmic contact P+ region 13 and the Schottky contact portion 18a are connected to the anode 12 and are located at the upper right of the entire device. The MPS anode 12 is shorted to the emitter 16 of the IGBT region, and the MPS cathode 11 is shorted to the collector 9 of the IGBT region. When the entire device enters the reverse operating state, the diode conducts when the voltage drop between the emitter 16 and the collector 9 exceeds the MPS threshold voltage, thus realizing the reverse conduction function of the RC-LIGBT. Since the main charge carriers when the MPS is turned on are electrons, the reverse recovery performance of this structure is higher than that of ordinary RC-LIGBT and RC-LIGBT with a pin diode in the reverse part.

[0060] When the device is forward-biased, the new structure operates in the same manner as a conventional IGBT. The gate voltage of the cathode MOS gradually increases, opening the electron channel and allowing electrons to be injected into the drift region from the emitter. When enough electrons accumulate below the N-type buffer layer, the IGBT's PNP transistor turns on and injects holes into the drift region, thus entering a bipolar operating mode. The reverse MPS diode is off at this time. Because there is no N+ anode region like in a traditional RC-LIGBT, the PNP transistor can turn on early, allowing the device to enter bipolar mode. This structure avoids negative resistance during forward conduction and eliminates voltage foldback. The integrated MPS diode can be considered a parallel combination of a PIN diode and a Schottky diode. During reverse conduction, the Schottky diode provides the main electron current, while the PIN diode provides a small amount of bipolar current. This unique operating mode enables the device to achieve good reverse recovery performance at a relatively low reverse conduction voltage.

[0061] Using SENTAURUS simulation software, the LIGBT device in the proposed implementation case 2 was simulated as follows: Figure 3 The structure shown was subjected to performance simulation analysis to analyze its mechanism and electrical simulation. During the simulation, all simulation parameters of the device in Example 2 were consistent with those of the conventional device, with a carrier lifetime of 10 μs and an ambient temperature of 300 K.

[0062] Figure 4 The diagram shown is the equivalent circuit diagram of the RC-LIGBT device in Example 2, where the IGBT is equivalent to an NMOS-controlled PNP transistor; the MPS diode can be regarded as a parallel connection of a PIN diode and a Schottky diode.

[0063] Figure 11 By comparing the forward conduction performance of Example 2 with that of a conventional RC-LIGBT and a conventional LIGBT, it can be seen that the device structure of Example 2 maintains the same level of forward conduction performance as the conventional LIGBT while eliminating the negative resistance effect of the conventional RC-LIGBT, thus improving the reliability of the device.

[0064] Figure 12 The breakdown voltage characteristic curve of Example 2 is compared with that of a conventional LIGBT. The breakdown voltage of Example 2 is 266V. Because Example 2 introduces a reverse freewheeling section, there will be a small leakage current in the reverse section when the forward voltage is applied, resulting in a breakdown voltage that is slightly lower than that of a conventional LIGBT. However, the overall difference is not significant and does not affect the reliability of the device much.

[0065] Figure 13 Comparing the turn-off performance of Example 2 with that of a conventional LIGBT, it can be seen that the turn-off performance of Example 2 is not much different from that of a conventional LIGBT. The slightly slower turn-off is caused by the leakage current in the reverse section.

[0066] Figure 14 For the comparison of reverse conduction performance of Example 2 with Example 1 and conventional RC-LIGBT, most of the reverse conduction current of MPS diode is provided by Schottky diode, with only a small portion of current flowing through PIN diode region; the reverse performance of Example 2 is also higher than that of conventional RC-LIGBT.

[0067] Figure 15 The graph shows a comparison of the reverse recovery performance of Example 2 and Example 1. Compared with the device structure of Example 1, the reverse recovery peak current of Example 2 is reduced by 38% and the reverse recovery time is reduced by 37.4%.

[0068] Example 3:

[0069] like Figure 5 As shown, the present invention proposes an RC-LIGBT device with a reverse freewheeling section consisting of a MOS Channel Diode. Its main structural feature is that the device is divided into a LIGBT region and a reverse-conducting MOS region from left to right. The ChannelDiode region is divided into two regions by an oxide isolation layer 10. The LIGBT region includes a P+ emitter 1, an N+ electron emitter 2, a P-base 3, an N-type drift region 4, a silicon dioxide insulating layer 5, a P-type substrate 6, an N-type buffer layer 7, a P+ collector 8, a collector 9, a gate 17, and an emitter 16. The right side of the P+ emitter 1 is closely connected to the left side of the N+ electron emitter 2. Their upper sides are flush with the upper side of the device and located in the upper left of the entire device. The lower end of the P+ emitter 1, the lower end of the N+ electron emitter 2, and the right end are wrapped by the P-base 3. The right end and the lower end of the P-base 3 are closely connected to the N-type drift region 4. The right side of the P+ collector is closely connected to the oxide isolation layer 10. Its upper end is flush with the upper side of the device. Its left and lower sides are completely wrapped by the N-type buffer layer 7. The left and lower sides of the N-type buffer layer 7 are closely connected to the N-type drift region 4.

[0070] The reverse portion is the reverse region of the RC-LIGBT of the MOS Channel Diode: from left to right, it comprises the cathode N+ region 15, the MOS Channel Diode drift region 14, the MOS Channel Diode P-base region 18b, the MOS Channel Diode anode N+ region 20, the MOS Channel Diode anode P+ region 13, the MOS Channel Diode gate oxide layer 19, the MOS Channel Diode anode 12, and the MOS Channel Diode cathode 11. The anode P+ region 13 and anode N+ region 20 of the MOS Channel Diode are tightly connected and enclosed by the MOS Channel Diode P-base region 18b. The left side of the MOS Channel Diode cathode N+ region 15 is tightly connected to the oxide isolation layer 10. The gate oxide layer 19 is connected to the upper side of the MOS Channel Diode P-base region 18b, the MOS Channel Diode drift region 14, and the MOS Channel Diode anode N+ region 20. The MOS Channel Diode gate oxide layer 19 is shorted to the MOS Channel Diode anode 12. When the entire device is in reverse operation, a positive voltage is applied to anode 12. Since the gate oxide layer 19 is shorted to anode 12, when the applied voltage is greater than the threshold voltage, the electron channel of the MOS Channel Diode is turned on, and the device conducts. The MOS Channel Diode provides freewheeling current. The P+ region 13 of the MOS Channel Diode anode, the drift region 14 of the MOS Channel Diode, and the N+ region of the cathode form a pin diode, which also provides freewheeling current during reverse conduction.

[0071] Figure 6 This is the equivalent circuit diagram of the device in Example 3.

[0072] Figure 16 The curves showing the forward conduction performance of Example 3 compared with those of a conventional RC-LIGBT and a conventional LIGBT demonstrate that Example 3 eliminates the negative resistance effect of a conventional RC-LIGBT without sacrificing forward conduction performance.

[0073] Figure 17 The curves showing the positive blocking performance of Example 3 compared to those of a conventional LIGBT demonstrate that Example 3 eliminates the negative resistance effect without sacrificing the positive blocking performance during the process.

[0074] Figure 18The curves showing the turn-off performance of Example 3 compared to those of a conventional LIGBT indicate that the turn-off performance of Example 3 is not significantly different from that of a conventional LIGBT. The slightly slower turn-off is due to leakage current in the reverse section.

[0075] Figure 19 The graph shows a comparison of the reverse recovery performance of Example 3 and Example 1. Compared with the device structure of Example 1, the reverse recovery peak current of Example 3 is reduced by 39% and the reverse recovery time is reduced by 38.5%.

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. An RC-LIGBT device capable of independently designing FWD, characterized in that: The RC-LIGBT device includes a LIGBT region and a reverse freewheeling region. The reverse freewheeling region includes a reverse freewheeling section that can be independently mounted in the region. The reverse freewheeling section is configured as an MPS freewheeling section or a MOS Channel Diode freewheeling section. The MPS freewheeling section includes, from left to right, a cathode N+ region (15), an MPS drift region (14), an ohmic contact P+ region (13), a Schottky contact portion (18a), an anode (12), and a cathode (11); the MPS section is separated from the IGBT region by an oxide isolation layer (10), the left side of the cathode N+ region is connected to the oxide isolation layer (10), the ohmic contact P+ region (13) and the Schottky contact portion (18a) are connected to the anode (12) and are located at the upper right of the entire device, the MPS anode (12) is short-circuited to the emitter (16) of the IGBT region, and the MPS cathode (11) is short-circuited to the collector (9) of the IGBT region; The MOS Channel Diode freewheeling section includes, from left to right, a cathode N+ region (15), a MOS Channel Diode drift region (14), a MOS Channel Diode P-base region (18b), a MOS Channel Diode anode N+ region (20), a MOS Channel Diode anode P+ region (13), a MOS Channel Diode gate oxide layer (19), a MOS Channel Diode anode (12), and a MOS Channel Diode cathode (11). The anode P+ region (13) and anode N+ region (20) of the MOS Channel Diode section are connected and are enclosed by the MOS Channel Diode P-base region (18b). The MOS Channel Diode freewheeling section is separated from the IGBT region by an oxide isolation layer (10). The left side of the MOS Channel Diode cathode N+ region (15) is connected to the oxide isolation layer (10). The gate oxide layer (19) is connected to the MOS Channel Diode P-base region (18b), the MOS Channel Diode drift region (14), and the MOS Channel Diode cathode N+ region (12). The upper side of the N+ region (20) of the Diode anode is connected; the gate oxide layer (19) of the MOSChannel Diode is shorted to the anode (12) of the MOS Channel Diode.

2. The RC-LIGBT device with independently designable FWD according to claim 1, characterized in that: The LIGBT region includes a P+ emitter (1), an N+ electron emitter (2), a P-base (3), an N-type drift region (4), a silicon dioxide insulating layer (5), a P-type substrate (6), an N-type buffer layer (7), a P+ collector (8), a collector (9), a gate (17), and an emitter (16).

3. The RC-LIGBT device with independently designable FWD according to claim 2, characterized in that: The LIGBT region is configured as follows: from left to right, it consists of a P+ emitter (1), an N+ electron emitter (2), a P-base (3), an N-type drift region (4), a silicon dioxide insulating layer (5), a P-type substrate (6), an N-type buffer layer (7), a P+ collector (8), a collector (9), a gate (17), and an emitter (16); the P+ emitter (1) is located below the emitter (16), its left side is flush with the left side of the device, its right side is connected to the left side of the N+ electron emitter (2), and its bottom side is connected to the P-base (3); the N+ electron emitter (2) is located below the emitter (16) and the gate (17), and its right and bottom sides are completely covered by the P-base (3); the upper side of the P-base (3) is flush with the upper side of the P+ emitter (1) and the N+ electron emitter (2), and its right and bottom sides are covered by the N-type drift region (4). 4) Complete coverage; the upper side of the N-type drift region (4) is flush with the upper side of the P+ emitter (1), N+ electron emitter (2), N-type buffer layer (7), and P+ collector (8), and the lower side is connected to the upper side of the silicon dioxide insulating layer (5). The left side is flush with the left side of the P+ emitter (1), P-base (3), silicon dioxide insulating layer (5), and P-type substrate (6), and the right side is flush with the right side of the silicon dioxide insulating layer (5) and P-type substrate (6). The upper side of the N-type buffer layer (7) is flush with the upper side of the P+ collector (8), and the right side is flush with the right side of the oxide isolation layer (10). The left and lower sides are completely covered by the N-type drift region (4). The P+ collector (8) is located below the collector (9). Its upper side is attached to the lower side of the collector (9). Its right side is flush with the oxide isolation layer (10), and its left and lower sides are completely covered by the N-type buffer layer (7).

Images