RC-IGBT structure and manufacturing method thereof, semiconductor device

Abstract

The application discloses an RC-IGBT structure and a manufacturing method thereof and a semiconductor device. The RC-IGBT structure comprises a substrate, a drift region of a first conductive type, a trench gate, a body region of a second conductive type, an emitter region of the first conductive type, a first contact region of the second conductive type and an isolation region of the second conductive type. The substrate has a first surface and a second surface facing away in a first direction, and comprises an IGBT region, a transition region and an FRD region arranged in sequence along a second direction. The trench gate comprises an active gate and a dummy gate arranged at intervals along the second direction. The isolation region is arranged in the transition region and between adjacent dummy gates, and is arranged on a side of the drift region facing the second surface. The doping concentration of the isolation region is greater than that of the body region. According to the RC-IGBT structure and the manufacturing method thereof and the semiconductor device, the performance of the IGBT region and the FRD region can be better separated and regulated.

Description

Technical Field

[0001] This application relates to the technical field of semiconductors, specifically to an RC-IGBT structure and its manufacturing method, and a semiconductor device. Background Technology

[0002] Currently, the IGBT (Insulated Gate Bipolar Transistor) is a MOS-bipolar composite transistor developed based on the Metal Oxide Semiconductor Field Effect Transistor (MOSFET). It combines the advantages of both power bipolar transistors and power MOSFETs, but possesses different strengths in on-state voltage drop and switching characteristics, thus becoming a core device in power supply, drive, and control circuits. Among them, the RC-IGBT (Reverse Conducting IGBT) is a power device that integrates an FRD (Fast Recovery Diode) and an IGBT.

[0003] In related technologies, it is difficult to separately control the performance of the IGBT region and the FRD region in RC-IGBT, which limits the performance of RC-IGBT.

[0004] Therefore, improvements are needed to at least partially address the aforementioned problems. Summary of the Invention

[0005] The summary section introduces a series of simplified concepts, which will be further explained in detail in the detailed description section. This summary section is not intended to limit the key and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0006] To at least partially solve the above problems, according to a first aspect of this application, an RC-IGBT structure is provided, comprising:

[0007] The substrate has a first surface and a second surface facing away from each other in a first direction, and the substrate includes an IGBT region, a transition region and an FRD region arranged sequentially along a second direction, the second direction being perpendicular to the first direction;

[0008] A drift region of a first conductivity type is disposed between the first surface and the second surface;

[0009] A trench gate, extending from the second surface into the drift region, includes an active gate and a dummy gate, wherein the active gate is disposed within the IGBT region and the dummy gate is spaced apart from the active gate along the second direction;

[0010] A body region of the second conductivity type is disposed within the IGBT region and the FRD region. The body region is disposed on the side of the drift region facing the second surface and located between adjacent trench gates.

[0011] An emitter region of a first conductivity type and a first contact region of a second conductivity type are disposed outside the active gate and on the side of the body region facing the second surface, and the emitter region and the first contact region on the side away from the body region constitute a portion of the second surface;

[0012] An isolation region of the second conductivity type is disposed within the transition region and between adjacent virtual gates, and the isolation region is disposed on the side of the drift region facing the second surface, wherein the doping concentration of the isolation region is greater than the doping concentration of the body region.

[0013] The above technical solution has the following advantages and beneficial effects: According to the RC-IGBT structure of this application, the isolation region of the second conductivity type is disposed in the transition region and between adjacent virtual gates, and the isolation region is disposed on the side of the drift region facing the second surface, and the doping concentration of the isolation region is greater than the doping concentration of the bulk region. The isolation region plays the role of electric field cutoff, which can reduce the influence between the IGBT region and the FRD region processes, and thus can better control the performance of the IGBT region and the FRD region separately.

[0014] Optionally, the side of the isolation zone away from the drift zone constitutes a portion of the second surface; or,

[0015] The isolation zone is further provided with a body region on the side facing the second surface, and the side of the body region away from the isolation zone constitutes a portion of the second surface.

[0016] The above technical solution has the following advantages and benefits: by setting it up in this way, the influence between the IGBT region and the FRD region processes can be reduced, thereby enabling better separate control of the performance of the IGBT region and the FRD region.

[0017] Optionally, it further includes a second contact region of a second conductivity type and a third contact region of a first conductivity type. The second contact region and the third contact region are disposed within the FRD region and between adjacent virtual gates. The second contact region and the third contact region are disposed on the side of the body region facing the second surface. The side of the second contact region and the third contact region away from the body region constitutes a portion of the second surface. The doping concentration of the second contact region is greater than the doping concentration of the body region, and the doping concentration of the third contact region is less than the doping concentration of the emitter region.

[0018] The above technical solution has the following advantages and beneficial effects: the third contact area of ​​the first conductivity type can reduce the amount of carriers injected from the second contact area into the drift region of the FRD region, thereby reducing the reverse recovery current of the FRD region and thus reducing the switching loss of the RC-IGBT.

[0019] Optionally, the number of third contact areas between adjacent virtual gates is at least two, and the at least two third contact areas are spaced apart along a third direction, which is perpendicular to the first direction and the second direction.

[0020] The above technical solution has the following advantages and benefits: By setting it up in this way, the amount of carriers injected from the second contact area into the drift region of the FRD region can be reduced, thereby reducing the reverse recovery current of the FRD region and thus reducing the switching loss of the RC-IGBT.

[0021] Optionally, the third contact region is a lightly doped region.

[0022] The above technical solution has the following advantages and benefits: By setting it up in this way, the amount of carriers injected from the second contact area into the drift region of the FRD region can be reduced, thereby reducing the reverse recovery current of the FRD region and thus reducing the switching loss of the RC-IGBT.

[0023] Optionally, the active gate is disposed in a first gate trench, the first gate trench extending from the second surface into the drift region, and the active gate includes a first gate dielectric layer located on the inner surface of the first gate trench and a first polysilicon gate filling the first gate trench.

[0024] The virtual gate is disposed in the second gate trench, which extends from the second surface into the drift region. The virtual gate includes a second gate dielectric layer located on the inner surface of the second gate trench and a second polysilicon gate filling the second gate trench.

[0025] The above technical solution has the following advantages and beneficial effects: the active gate plays a control role in the RC-IGBT. When the gate voltage is applied to the active gate, a conductive channel can be formed around the active gate, allowing electrons and holes to move in the channel, thereby controlling the turn-on and turn-off of the RC-IGBT; the virtual gate can reduce the feedback capacitance of the RC-IGBT.

[0026] Optionally, it also includes:

[0027] A collector region of the second conductivity type is disposed within the IGBT region and the transition region and on the side of the drift region facing the first surface, and the side of the collector region away from the drift region constitutes a portion of the first surface;

[0028] An injection region of a first conductivity type is disposed within the FRD region and is disposed parallel to the collector region on the side of the drift region facing the first surface, and the side of the injection region away from the drift region constitutes a portion of the first surface;

[0029] A field cutoff region of a first conductivity type is disposed between the current collecting region and the drift region, and between the injection region and the drift region.

[0030] The above technical solution has the following advantages and beneficial effects: The main function of the field cutoff region is to terminate the electric field in the RC-IGBT turn-off state, prevent the electric field from penetrating into the collector region, thereby improving the withstand voltage performance of the device.

[0031] According to a second aspect of this application, a method for manufacturing an RC-IGBT structure is provided, comprising:

[0032] A substrate is provided having a first surface and a second surface facing away from each other in a first direction, a drift region of a first conductivity type is formed between the first surface and the second surface of the substrate, and the substrate includes an IGBT region, a transition region and an FRD region arranged sequentially along a second direction, the second direction being perpendicular to the first direction;

[0033] A trench gate is formed extending from the second surface into the drift region. The trench gate includes an active gate and a dummy gate. The active gate is disposed within the IGBT region, and the dummy gate and the active gate are spaced apart along the second direction.

[0034] A body region of a second conductivity type is formed within the IGBT region and the FRD region, the body region being disposed on the side of the drift region facing the second surface and located between adjacent trench gates;

[0035] An isolation region of a second conductivity type is formed, the isolation region being disposed within the transition region and between adjacent virtual gates, and the isolation region being disposed on the side of the drift region facing the second surface, the doping concentration of the isolation region being greater than the doping concentration of the body region;

[0036] An emitter region of a first conductivity type and a first contact region of a second conductivity type are formed. The emitter region and the first contact region are disposed outside the active gate and on the side of the body region facing the second surface. The side of the emitter region and the first contact region away from the body region constitutes a portion of the second surface.

[0037] The above technical solution has the following advantages and beneficial effects: According to the manufacturing method of the RC-IGBT structure of this application, the isolation region of the second conductivity type is disposed in the transition region and between adjacent virtual gates, and the isolation region is disposed on the side of the drift region facing the second surface, and the doping concentration of the isolation region is greater than the doping concentration of the bulk region. The isolation region plays the role of electric field cutoff, which can reduce the influence between the IGBT region and the FRD region process, and thus can better control the performance of the IGBT region and the FRD region separately.

[0038] Optionally, after forming the emitter region and the first contact region, the method further includes forming a second contact region of a second conductivity type and a third contact region of a first conductivity type. The second contact region and the third contact region are disposed within the FRD region and between adjacent virtual gates. The second contact region and the third contact region are disposed on the side of the body region facing the second surface. The side of the second contact region and the third contact region away from the body region constitutes a portion of the second surface. The doping concentration of the second contact region is greater than the doping concentration of the body region, and the doping concentration of the third contact region is less than the doping concentration of the emitter region.

[0039] The above technical solution has the following advantages and beneficial effects: the third contact area of ​​the first conductivity type can reduce the amount of carriers injected into the drift region of the FRD region by the second contact area of ​​the second conductivity type, thereby reducing the reverse recovery current of the FRD region and thus reducing the switching loss of the RC-IGBT.

[0040] The semiconductor device according to the embodiments of this application includes the above-described RC-IGBT structure.

[0041] The above technical solution has the following advantages and beneficial effects: Since the semiconductor device according to this application includes the aforementioned RC-IGBT structure, it also has the advantages and beneficial effects of the aforementioned RC-IGBT structure. Attached Figure Description

[0042] The above and other objects, features, and advantages of this application will become more apparent from the more detailed description of the embodiments thereof in conjunction with the accompanying drawings. The drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the embodiments of this application to explain the application and do not constitute a limitation thereof. In the drawings, the same reference numerals generally represent the same components or steps.

[0043] Figures 1A-1I A cross-sectional view of an RC-IGBT structure obtained by sequentially implementing the manufacturing method of the RC-IGBT structure in an embodiment of this application is shown.

[0044] Figure 2 A cross-sectional view of an RC-IGBT structure according to another embodiment of this application is shown.

[0045] Figure 3 A flowchart illustrating the manufacturing method of the RC-IGBT structure in an embodiment of this application is shown.

[0046] Figure label:

[0047] 100. Substrate; 101. First surface; 102. Second surface; 110. Drift region; 121. Active gate; 122. Virtual gate; 130. Bulk region; 140. Isolation region; 150. Emitter region; 161. First contact region; 162. Second contact region; 163. Third contact region; 170. Field cutoff region; 180. Collector region; 190. Implantation region. Detailed Implementation

[0048] The following description provides numerous specific details to offer a more thorough understanding of this application. However, it will be apparent to those skilled in the art that this application can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described to avoid confusion with this application.

[0049] It should be understood that this application can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, providing these embodiments will make the disclosure thorough and complete, and will fully convey the scope of this application to those skilled in the art. In the drawings, for clarity, the dimensions and relative dimensions of layers and regions may be exaggerated. The same reference numerals denote the same elements throughout.

[0050] It should be understood that although the terms first, second, third, etc., may be used to describe various elements, components, areas, layers, and / or parts, these elements, components, areas, layers, and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, area, layer, or part from another element, component, area, layer, or part. Therefore, without departing from the teachings of this application, the first element, component, area, layer, or part discussed below may be referred to as the second element, component, area, layer, or part.

[0051] Spatial relation terms such as "below," "under," "below," "under," "above," and "above" are used here for convenience to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms are intended to also include different orientations of devices in use and operation.

[0052] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of this application. When used herein, the singular forms “a,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising” and / or “including,” when used in this specification, identify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups. When used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0053] Embodiments of the application are described herein with reference to cross-sectional views that serve as schematic diagrams of preferred embodiments (and intermediate structures). Thus, variations in the shown shapes due to, for example, manufacturing techniques and / or tolerances are expected. Therefore, embodiments of the application should not be limited to the specific shapes shown herein, but include shape deviations due to, for example, manufacturing processes. Consequently, the figures are substantially schematic, and their shapes are not intended to show the actual shape of the device and are not intended to limit the scope of the application.

[0054] In the RC-IGBT structure of related technologies, the IGBT region and the FRD region are in direct contact. When adjusting the performance of the IGBT region and the FRD region through the process, the processes of the IGBT region and the FRD region will affect each other, making it difficult to separately control the performance of the IGBT region and the FRD region.

[0055] like Figure 1I and Figure 2As shown, in order to solve the above problems, this application provides an RC-IGBT structure, which mainly includes: a substrate 100, a drift region 110 of a first conductivity type, a trench gate, a body region 130 of a second conductivity type, an emitter region 150 of a first conductivity type, a first contact region 161 of a second conductivity type, and an isolation region 140 of a second conductivity type.

[0056] First, it should be noted that in this article, N and P represent the conductivity type of the semiconductor. The following explanation will use N-type as the first conductivity type and P-type as the second conductivity type.

[0057] Substrate 100 has in a first direction ( Figure 1I and Figure 2 The first surface 101 and the second surface 102 are mutually opposite in the vertical direction, and the first surface 101 and the second surface 102 are spaced apart along the first direction.

[0058] Substrate 100 includes components along the second direction ( Figure 1I and Figure 2 The IGBT region, transition region, and FRD region are arranged sequentially in the left-right direction (with the second direction perpendicular to the first direction). The IGBT region is the main area responsible for current conduction in the RC-IGBT, and the channel is formed within the IGBT region. The FRD region is the area in the RC-IGBT that provides freewheeling and reverse current.

[0059] For example, the substrate 100 may be any suitable semiconductor substrate, such as a silicon substrate, and may also be at least one of the following materials: Si, Ge, SiGe, SiC, SiGeC, InAs, GaAs, InP or other III / V compound semiconductors, including multilayer structures made of these semiconductor materials, or silicon on insulator (SOI), silicon on insulator stacked on insulator (SSOI), silicon on insulator stacked on insulator (S-SiGeOI), silicon on insulator (SiGeOI), and germanium on insulator (GeOI).

[0060] The drift region 110 is located between the first surface 101 and the second surface 102. The drift region 110 determines the saturation voltage drop and voltage level of the RC-IGBT and is the main region affecting the switching speed of the RC-IGBT. The conductivity type of the drift region 110 is the first conductivity type.

[0061] The trench gate extends from the second surface into the drift region 110. The trench gate includes an active gate 121 and a dummy gate 122. The active gate 121 is disposed within the IGBT region, and the dummy gate 122 is spaced apart from the active gate 121 along the second direction. For example, Figure 1I and Figure 2The RC-IGBT shown has one active gate 121 and multiple virtual gates 122. However, this does not mean that the number of active gates 121 can only be one. In other embodiments, multiple active gates 121 can be provided. When multiple active gates 121 are provided, the arrangement of active gates 121 and virtual gates 122 can be reasonably set as needed. This application does not impose any restrictions on this.

[0062] The active gate 121 plays a control role in the RC-IGBT. When the gate voltage is applied to the active gate 121, a conductive channel can be formed around the active gate 121, allowing electrons and holes to move in the channel, thereby controlling the RC-IGBT to turn on and off.

[0063] The dummy gate 122 is a gate structure present in the RC-IGBT structure but not directly involved in conduction; it typically cannot form a conductive channel. The dummy gate 122 is in contact with the emitter metal (not shown), that is, the dummy gate 122 is short-circuited with the emitter region 150 (the emitter metal contacts the emitter region 150 to lead out the emitter region 150). By short-circuiting the dummy gate 122 with the emitter region, the dummy gate 122 and the emitter region 150 can have the same properties, being negatively charged. This can attract some holes to transfer to the dummy gate 122, thereby reducing the number of holes flowing below the emitter region 150, i.e., reducing the number of holes flowing in the channel, lowering the risk of latch-up under high current conditions, and also reducing the feedback capacitance of the RC-IGBT (i.e., the gate-collector capacitance), thereby reducing switching losses. Exemplarily, the dummy gate 122 can also be called a dummy cell narrow trench gate.

[0064] A body region 130 (also referred to as a base region) of the second conductivity type is disposed within the IGBT region and the FRD region, and the body region 130 is disposed on the side of the drift region 110 facing the second surface 102 and located between adjacent trench gates. Exemplarily, the body region 130 is located between the active gate 121 and the dummy gate 122, and between adjacent dummy gates 122.

[0065] The emitter region 150 of the first conductivity type is disposed outside the active gate 121 (on both sides of the active gate 121 along the second direction) and on the side of the body region 130 facing the second surface 102, and the side of the emitter region 150 away from the body region 130 constitutes a portion of the second surface 102. The doping concentration of the emitter region 150 of the first conductivity type is higher than the doping concentration of the drift region 110.

[0066] The first contact region 161 of the second conductivity type is disposed outside the active gate 121 and on the side of the body region 130 facing the second surface 102, and the side of the emitter region 150 away from the body region 130 constitutes a portion of the second surface 102. The doping concentration of the first contact region 161 is higher than that of the body region 130. By simultaneously providing the emitter region 150 of the first conductivity type and the first contact region 161 of the second conductivity type, the current output capability of the RC-IGBT is effectively improved. Exemplarily, the number of first contact regions 161 located on one side of the active gate 121 is at least two, and the at least two first contact regions 161 are spaced apart along a third direction, which is perpendicular to the first direction and the second direction. Exemplarily, both the emitter region 150 and the first contact region 161 are heavily doped regions.

[0067] The isolation region 140 of the second conductivity type is disposed within the transition region and between adjacent virtual gates 122. The isolation region 140 is located on the side of the drift region 110 facing the second surface 102, and the doping concentration of the isolation region 140 is greater than that of the bulk region. The transition region is located between the IGBT region and the FRD region. The isolation region 140 within the transition region acts as an electric field cutoff, reducing the influence between the IGBT region and the FRD region processes, thereby enabling better separate control of the performance of the IGBT region and the FRD region. For example, when performing an ion implantation process with varying doping concentration within the IGBT region (e.g., forming a first contact region 161 within the IGBT region with a doping concentration greater than that of the bulk region 130), the isolation region 140 acts as an electric field cutoff, ensuring that the ion implantation dose has almost no effect on the FRD region. Similarly, when performing an ion implantation process with varying doping concentration within the FRD region, it has almost no effect on the IGBT region. This allows for separate control of the doping concentration within the IGBT region and the FRD region. Since the doping concentration affects conduction and switching losses, this allows for better separate control of the conduction and switching losses between the IGBT region and the FRD region. For instance, the isolation region 140 is a heavily doped region; taking P-type as an example, the isolation region 140 is a P+ doped region.

[0068] like Figure 2 As shown, the side of the isolation zone 140 away from the drift zone 110 constitutes part of the second surface 102; or, as Figure 1I As shown, a body region 130 is also provided on the side of the isolation region 140 facing the second surface 102. The side of the body region 130 away from the isolation region 140 constitutes part of the second surface. The isolation region 140 is disposed between the body region 130 and the drift region 110.

[0069] Furthermore, such as Figure 1I and Figure 2As shown, the RC-IGBT structure also includes a second contact region 162 of a second conductivity type and a third contact region 163 of a first conductivity type. The second contact region 162 and the third contact region 163 are disposed within the FRD region and between adjacent virtual gates 122. The second contact region 162 and the third contact region 163 are located on the side of the body region 130 facing the second surface 102. The side of the second contact region 162 and the third contact region 163 away from the body region 130 constitutes a portion of the second surface 102. The doping concentration of the second contact region 162 is greater than that of the body region 130, and the doping concentration of the third contact region 163 is less than that of the emitter region 150. The second contact region 162 can enhance the current output capability. For example, the second contact region 162 is a heavily doped region.

[0070] When the FRD region in the RC-IGBT is forward-biased, the second contact region 162 injects holes into the drift region 110 of the FRD region. When the RC-IGBT is turned on (IGBT region is forward-biased), the FRD region undergoes reverse recovery. At this time, because the holes in the drift region 110 need to be extracted, a large reverse recovery current is generated, resulting in increased switching losses. However, the third contact region 163 provided in this application does not inject holes into the drift region 110 when the FRD region is forward-biased. Simultaneously, the third contact region 163 can provide free electrons to recombine the holes in the second contact region 162, thereby reducing the amount of holes injected into the drift region 110 by the second contact region 162 when the FRD region is forward-biased, thus reducing the amount of holes that the FRD region needs to extract during reverse recovery, and consequently reducing switching losses. For example, the third contact region 163 is a lightly doped region. For example, by adjusting the proportion of the third contact area 163, the balance between the forward conduction voltage and the reverse recovery current of the FRD area can be optimized, thereby adjusting the conduction loss and switching loss of the RC-IGBT.

[0071] The number of third contact areas 163 between adjacent virtual gates 122 is at least two, and the at least two third contact areas 163 are spaced apart along a third direction.

[0072] In some embodiments, a first gate trench extending from the second surface 102 into the drift region 110 is formed in the substrate, and an active gate 121 is disposed within the first gate trench. The active gate 121 includes a first gate dielectric layer located on the inner surface of the first gate trench and a first polysilicon gate filling the first gate trench. Exemplarily, the first gate dielectric layer may be a silicon dioxide layer.

[0073] In some embodiments, a second gate trench extending from the second surface 102 into the drift region 110 is formed in the substrate, and a virtual gate 122 is disposed within the second gate trench. The virtual gate 122 includes a second gate dielectric layer located on the inner surface of the second gate trench and a second polysilicon gate filling the second gate trench. Exemplarily, the second gate dielectric layer may be a silicon dioxide layer.

[0074] In some embodiments, the second polysilicon gate in the virtual gate 122 can be a floating gate, that is, the second polysilicon gate is a gate that is not directly electrically connected to an external circuit. It is surrounded by an insulating layer and is in a "floating" state, not directly connected to a fixed potential point such as power supply or ground.

[0075] Furthermore, such as Figure 1I and Figure 2 As shown, the RC-IGBT structure also includes a collector region 180 of a second conductivity type. The collector region 180 is disposed in the IGBT region and the transition region and is disposed on the side of the drift region 110 facing the first surface 101. The side of the collector region 180 away from the drift region 110 constitutes part of the first surface 101.

[0076] Furthermore, such as Figure 1I and Figure 2 As shown, the RC-IGBT structure also includes an injection region 190 of a first conductivity type. The injection region 190 is disposed in the FRD region and is disposed in parallel with the collector region 180 on the side of the drift region 110 facing the first surface 101. The side of the injection region 190 away from the drift region 110 constitutes part of the first surface 101.

[0077] Furthermore, such as Figure 1I and Figure 2 As shown, the RC-IGBT structure also includes a field-stop region 170 of a first conductivity type, which is disposed between the collector region 180 and the drift region 110, and between the injection region 190 and the drift region 110. The doping concentration of the field-stop region 170 is higher than that of the drift region 110. The main function of the field-stop region 170 is to terminate the electric field in the RC-IGBT's off state, preventing the electric field from penetrating to the collector region 180, thereby improving the device's breakdown voltage capability. When a high voltage is applied, the field-stop region 170 can withstand a portion of the electric field, causing the electric field to gradually weaken before reaching the collector region 180, thus preventing breakdown in the collector region 180. The field-stop region 170 can also reduce the duration and amplitude of the tail current by adjusting the carrier distribution and extraction speed. Reducing the tail current helps to reduce turn-off losses.

[0078] In the RC-IGBT structure of this application embodiment, the isolation region of the second conductivity type serves to cut off the electric field, reducing the influence between the IGBT region and the FRD region processes, thereby enabling better separate control of the IGBT region and the FRD region performance. Exemplarily, it also includes a third contact region of the first conductivity type. The third contact region reduces the amount of holes injected into the drift region by the second contact region when the FRD region is forward-biased, thereby reducing the reverse recovery current and thus reducing switching losses.

[0079] This application also provides a method for manufacturing an RC-IGBT structure, which is used to manufacture the RC-IGBT structure described above, as follows (see below) Figures 1A-1I , Figure 2 as well as Figure 3 A method for manufacturing an RC-IGBT structure according to an embodiment of this application is described exemplarily.

[0080] First, execute step S1, as follows: Figure 1A As shown, a substrate 100 is provided, the substrate 100 having a first surface 101 and a second surface 102 facing away from each other in a first direction, a drift region 110 of a first conductivity type is formed between the first surface 101 and the second surface 102 of the substrate 100, and the substrate 100 includes an IGBT region, a transition region and an FRD region arranged sequentially along a second direction, the second direction being perpendicular to the first direction.

[0081] Next, proceed to step S2, as follows: Figure 1A As shown, a trench gate is formed extending from the second surface 102 into the drift region 110. The trench gate includes an active gate 121 and a virtual gate 122. The active gate 121 is disposed within the IGBT region, and the virtual gate 122 is spaced apart from the active gate 121 along the second direction.

[0082] Next, proceed to step S3, as follows: Figure 1B As shown, a body region 130 of a second conductivity type is formed within the IGBT region and the FRD region. The body region 130 is disposed on the side of the drift region 110 facing the second surface 102 and located between adjacent trench gates. Exemplarily, the body region 130 is formed by an ion implantation process.

[0083] Next, proceed to step S4, as follows: Figure 1C An isolation region 140 of a second conductivity type is formed. The isolation region 140 is disposed within the transition region and between adjacent virtual gates 122, and the isolation region 140 is disposed on the side of the drift region 110 facing the second surface 102. The doping concentration of the isolation region 140 is greater than that of the bulk region. Exemplarily, the isolation region 140 is formed by an ion implantation process.

[0084] A transition region is located between the IGBT region and the FRD region. An isolation region 140 within the transition region acts as an electric field cutoff, reducing the impact of the IGBT and FRD processes on each region and allowing for better separate control of their performance. For example, when performing an ion implantation process with varying doping concentration in the IGBT region (e.g., forming a first contact region 161 with a doping concentration greater than that of the bulk region 130), the isolation region 140 acts as an electric field cutoff, ensuring that the ion implantation dose has almost no effect on the FRD region. Similarly, when performing an ion implantation process with varying doping concentration in the FRD region, it has almost no effect on the IGBT region. This allows for separate control of the doping concentration in the IGBT and FRD regions. Since doping concentration affects conduction and switching losses, this allows for better separate adjustment of the conduction and switching losses in the IGBT and FRD regions.

[0085] In one example, such as Figure 2 As shown, the side of the isolation zone 140 away from the drift zone 110 constitutes part of the second surface 102; or, as Figure 1B and 1C As shown, a body region 130 of the second conductivity type is formed in the IGBT region and the FRD region, while a body region 130 is also formed in the transition region, and an isolation region 140 is disposed between the body region 130 and the drift region 110.

[0086] Next, proceed to step S5, as follows: Figure 1D and Figure 1E As shown, an emitter region 150 of a first conductivity type and a first contact region 161 of a second conductivity type are formed. The emitter region 150 and the first contact region 161 are disposed outside the active gate 121 and on the side of the body region 130 facing the second surface 102. The side of the emitter region 150 and the first contact region 161 away from the body region 130 constitutes a portion of the second surface 102. Specifically, as... Figure 1D As shown, an emitter region 150 of the first conductivity type is first formed; then, as shown... Figure 1E As shown, a first contact region 161 of a second conductivity type is formed. Exemplarily, the emitter region 150 and the first contact region 161 are formed by an ion implantation process.

[0087] Furthermore, such as Figure 1F and Figure 1GAs shown, after forming the emitter region 150 and the first contact region 161, the method further includes forming a second contact region 162 of a second conductivity type and a third contact region 163 of a first conductivity type. The second contact region 162 and the third contact region 163 are disposed within the FRD region and between adjacent virtual gates 122. The second contact region 162 and the third contact region 163 are disposed on the side of the body region 130 facing the second surface 102, and the side of the second contact region 162 and the third contact region 163 away from the body region 130 constitutes a portion of the second surface 102. The doping concentration of the second contact region 162 is greater than the doping concentration of the body region 130, and the doping concentration of the third contact region 163 is less than the doping concentration of the emitter region 150. Specifically, as... Figure 1F As shown, a third contact region 163 is first formed; then, as shown in 1G, a second contact region 162 of a second conductivity type is formed. Exemplarily, the second contact region 162 and the third contact region 163 are formed by an ion implantation process.

[0088] When the FRD region in the RC-IGBT is forward-biased, the second contact region 162 injects holes into the drift region 110 of the FRD region. When the RC-IGBT is turned on (IGBT region is forward-biased), the FRD region undergoes reverse recovery. At this time, because the holes in the drift region 110 need to be extracted, a large reverse recovery current is generated, resulting in increased switching losses. However, the third contact region 163 provided in this application does not inject holes into the drift region 110 when the FRD region is forward-biased. Simultaneously, the third contact region 163 can provide free electrons to recombine the holes in the second contact region 162, thereby reducing the amount of holes injected into the drift region 110 by the second contact region 162 when the FRD region is forward-biased, thus reducing the amount of holes that the FRD region needs to extract during reverse recovery, and consequently reducing switching losses. For example, the third contact region 163 is a lightly doped region. For example, by adjusting the proportion of the third contact area 163, the balance between the forward conduction voltage and the reverse recovery current of the FRD area can be optimized, thereby adjusting the conduction loss and switching loss of the RC-IGBT.

[0089] Furthermore, such as Figure 1H and Figure 1IAs shown, the method also includes the steps of forming a field cutoff region 170 of a first conductivity type, a collector region 180 of a second conductivity type, and an injection region 190 of the first conductivity type. The collector region 180 is disposed within the IGBT region and the transition region, and is located on the side of the drift region 110 facing the first surface 101, with the side of the collector region 180 away from the drift region 110 forming a portion of the first surface 101. The injection region 190 is disposed within the FRD region and is arranged parallel to the collector region 180 on the side of the drift region 110 facing the first surface 101, with the side of the injection region 190 away from the drift region 110 forming a portion of the first surface 101. The field cutoff region 170 is disposed between the collector region 180 and the drift region 110, and between the injection region 190 and the drift region 110. Specifically, as follows... Figure 1H As shown, a field cutoff region 170 of the first conductivity type is formed; and as another example... Figure 1I As shown, a collector region 180 of a second conductivity type and an implantation region 190 of a first conductivity type are formed. Exemplarily, a field cutoff region 170, a collector region 180, and an implantation region 190 are formed by an ion implantation process.

[0090] The manufacturing method of the RC-IGBT structure in this application embodiment uses an isolation region of the second conductivity type to cut off the electric field, reducing the influence between the IGBT region and the FRD region processes, and thus enabling better separate control of the IGBT region and the FRD region performance. Exemplarily, a third contact region of the first conductivity type is also formed. This third contact region reduces the amount of holes injected into the drift region by the second contact region when the FRD region is forward-biased, thereby reducing the reverse recovery current and further reducing switching losses.

[0091] This application also provides a semiconductor device comprising the RC-IGBT structure described above. The semiconductor device can be a power semiconductor device.

[0092] Although exemplary embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above exemplary embodiments are merely illustrative and are not intended to limit the scope of this application. Various changes and modifications can be made therein by those skilled in the art without departing from the scope and spirit of this application. All such changes and modifications are intended to be included within the scope of this application as claimed in the appended claims.

[0093] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of this application may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0094] Similarly, it should be understood that, in order to streamline this application and aid in understanding one or more of the various inventive aspects, features of this application may sometimes be grouped together in a single embodiment, figure, or description thereof in the description of exemplary embodiments of this application. However, this approach should not be construed as reflecting an intention that the claimed application requires more features than are expressly recited in each claim. Rather, as reflected in the corresponding claims, its inventive point lies in solving the corresponding technical problem with features fewer than all features of a single disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of this application.

[0095] Those skilled in the art will understand that, apart from the mutual exclusion of features, all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or units of any method or apparatus so disclosed can be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature that serves the same, equivalent, or similar purpose.

[0096] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features but not others included in other embodiments, combinations of features from different embodiments are intended to be within the scope of this application and form different embodiments. For example, in the claims, any one of the claimed embodiments can be used in any combination.

[0097] The above are merely specific embodiments or descriptions of specific embodiments of this application. The scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. The scope of protection of this application shall be determined by the scope of the claims.

Claims

1. An RC-IGBT structure, characterized in that, include: The substrate has a first surface and a second surface facing away from each other in a first direction, and the substrate includes an IGBT region, a transition region and an FRD region arranged sequentially along a second direction, the second direction being perpendicular to the first direction; A drift region of a first conductivity type is disposed between the first surface and the second surface; A trench gate, extending from the second surface into the drift region, includes an active gate and a dummy gate, wherein the active gate is disposed within the IGBT region and the dummy gate is spaced apart from the active gate along the second direction; A body region of the second conductivity type is disposed within the IGBT region and the FRD region. The body region is disposed on the side of the drift region facing the second surface and located between adjacent trench gates. An emitter region of a first conductivity type and a first contact region of a second conductivity type are disposed outside the active gate and on the side of the body region facing the second surface, and the emitter region and the first contact region on the side away from the body region constitute a portion of the second surface; An isolation region of the second conductivity type is disposed within the transition region and between adjacent virtual gates, and the isolation region is disposed on the side of the drift region facing the second surface, wherein the doping concentration of the isolation region is greater than the doping concentration of the bulk region; The side of the isolation zone away from the drift zone constitutes a portion of the second surface; or, the body region is further provided on the side of the isolation zone facing the second surface, and the side of the body region away from the isolation zone constitutes a portion of the second surface.

2. The RC-IGBT structure according to claim 1, characterized in that, It also includes a second contact region of a second conductivity type and a third contact region of a first conductivity type. The second contact region and the third contact region are disposed within the FRD region and between adjacent virtual gates. The second contact region and the third contact region are disposed on the side of the body region facing the second surface. The side of the second contact region and the third contact region away from the body region constitutes a portion of the second surface. The doping concentration of the second contact region is greater than the doping concentration of the body region, and the doping concentration of the third contact region is less than the doping concentration of the emitter region.

3. The RC-IGBT structure according to claim 2, characterized in that, The number of third contact areas between adjacent virtual gates is at least two, and the at least two third contact areas are spaced apart along a third direction, which is perpendicular to the first direction and the second direction.

4. The RC-IGBT structure according to claim 2 or 3, characterized in that, The third contact region is a lightly doped region.

5. The RC-IGBT structure according to any one of claims 1-3, characterized in that, The active gate is disposed in a first gate trench, the first gate trench extends from the second surface into the drift region, and the active gate includes a first gate dielectric layer located on the inner surface of the first gate trench and a first polysilicon gate filling the first gate trench. The virtual gate is disposed in the second gate trench, which extends from the second surface into the drift region. The virtual gate includes a second gate dielectric layer located on the inner surface of the second gate trench and a second polysilicon gate filling the second gate trench.

6. The RC-IGBT structure according to any one of claims 1-3, characterized in that, Also includes: A collector region of the second conductivity type is disposed within the IGBT region and the transition region and on the side of the drift region facing the first surface, and the side of the collector region away from the drift region constitutes a portion of the first surface; An injection region of a first conductivity type is disposed within the FRD region and is disposed parallel to the collector region on the side of the drift region facing the first surface, and the side of the injection region away from the drift region constitutes a portion of the first surface; A field cutoff region of a first conductivity type is disposed between the current collecting region and the drift region, and between the injection region and the drift region.

7. A method for manufacturing an RC-IGBT structure, characterized in that, include: A substrate is provided having a first surface and a second surface facing away from each other in a first direction, a drift region of a first conductivity type is formed between the first surface and the second surface of the substrate, and the substrate includes an IGBT region, a transition region and an FRD region arranged sequentially along a second direction, the second direction being perpendicular to the first direction; A trench gate is formed extending from the second surface into the drift region. The trench gate includes an active gate and a dummy gate. The active gate is disposed within the IGBT region, and the dummy gate and the active gate are spaced apart along the second direction. A body region of a second conductivity type is formed within the IGBT region and the FRD region, the body region being disposed on the side of the drift region facing the second surface and located between adjacent trench gates; An isolation region of a second conductivity type is formed, the isolation region being disposed within the transition region and between adjacent virtual gates, and the isolation region being disposed on the side of the drift region facing the second surface, the doping concentration of the isolation region being greater than the doping concentration of the body region; the side of the isolation region away from the drift region constitutes a portion of the second surface; or, the body region is further disposed on the side of the isolation region facing the second surface, and the side of the body region away from the isolation region constitutes a portion of the second surface; An emitter region of a first conductivity type and a first contact region of a second conductivity type are formed. The emitter region and the first contact region are disposed outside the active gate and on the side of the body region facing the second surface. The side of the emitter region and the first contact region away from the body region constitutes a portion of the second surface.

8. The manufacturing method according to claim 7, characterized in that, After forming the emitter region and the first contact region, the method further includes forming a second contact region of a second conductivity type and a third contact region of a first conductivity type. The second contact region and the third contact region are disposed within the FRD region and between adjacent virtual gates. The second contact region and the third contact region are disposed on the side of the body region facing the second surface. The side of the second contact region and the third contact region away from the body region constitutes a portion of the second surface. The doping concentration of the second contact region is greater than the doping concentration of the body region, and the doping concentration of the third contact region is less than the doping concentration of the emitter region.

9. A semiconductor device, characterized in that, The RC-IGBT structure includes any one of claims 1-6.

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