IGBT structure and manufacturing method thereof, semiconductor device

Abstract

The application discloses an IGBT structure, a manufacturing method thereof and a semiconductor device. The IGBT structure comprises a substrate, a drift region of a first conductive type, a plurality of trench gates, a body region of a second conductive type, an emitter region of the first conductive type, a guard ring of the second conductive type, a collector region of the second conductive type and a plurality of doped regions of the first conductive type. The substrate comprises an IGBT region and a termination region outside the IGBT region and has a first surface and a second surface which are opposite to each other in a first direction. The collector region is arranged on a side of the drift region facing the first surface, and a side of the collector region away from the drift region constitutes at least part of the first surface. The plurality of doped regions are arranged in the collector region of the termination region in a direction perpendicular to the first direction. The IGBT structure, the manufacturing method thereof and the semiconductor device can effectively reduce the turn-off loss without affecting the on-state voltage drop.

Description

Technical Field

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

[0002] Currently, IGBT (Insulated Gate Bipolar Transistor) is a MOS-bipolar composite transistor developed based on Metal Oxide Semiconductor Field Effect Transistor (MOSFET). It has the advantages of both power bipolar transistors and power MOSFETs, but has different advantages in on-state voltage drop and switching, thus becoming a core device in power supply, drive, and control circuits.

[0003] In related technologies, an IGBT includes an IGBT region and a terminal region located outside the IGBT region. A protective ring is formed in the terminal region to ensure withstand voltage. During the IGBT turn-on process, taking the collector region as a P-type conductivity type as an example, a large number of holes will accumulate in the terminal region, which will increase the number of holes that need to be discharged from the terminal region during the IGBT turn-off process, resulting in greater turn-off losses.

[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 IGBT structure is provided, comprising:

[0007] The substrate includes an IGBT region and a terminal region located outside the IGBT region, and the substrate has a first surface and a second surface that are opposite to each other in a first direction;

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

[0009] Multiple trench gates are spaced apart within the IGBT region and extend from the second surface into the drift region;

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

[0011] An emitting region of a first conductivity type is disposed on the side of the body region facing the second surface, and the side of the emitting region away from the body region constitutes at least a portion of the second surface;

[0012] A second conductive type of protective ring is disposed in the terminal region and extends from the second surface into the drift region;

[0013] A collector region of a second conductivity type is disposed on the side of the drift region facing the first surface, and the side of the collector region away from the drift region constitutes at least a portion of the first surface;

[0014] Multiple doped regions of a first conductivity type are spaced apart in the collector region of the terminal region along a direction perpendicular to the first direction.

[0015] The above technical solution has the following advantages and beneficial effects: According to the IGBT structure in this application, multiple doped regions of the first conductivity type are spaced apart in the collector region of the second conductivity type in the terminal region along a direction perpendicular to the first direction. This can reduce the amount of carriers injected into the drift region of the terminal region by the collector region of the terminal region during the IGBT turn-on process, thereby reducing the amount of carriers discharged during the turn-off process and reducing the turn-off loss. At the same time, it will not affect the on-state voltage drop of the IGBT.

[0016] Optionally, the terminal region has a first side adjacent to the IGBT region and a second side opposite to the first side, and from the second side to the first side, the width of the plurality of doped regions gradually increases in a direction perpendicular to the first direction; and / or

[0017] The thickness of the plurality of doped regions gradually increases in the first direction; and / or

[0018] The spacing between adjacent doped regions gradually decreases.

[0019] The above technical solution has the following advantages and beneficial effects: By setting it up in this way, the amount of carriers injected from the collector region of the terminal area to the drift region can be reduced during the IGBT turn-on process, while the amount of carriers flowing from the collector region of the IGBT area to the drift region of the terminal area can be reduced, thereby reducing the amount of carriers discharged during the turn-off process, further reducing the turn-off loss, and at the same time, it will not affect the IGBT's on-state voltage drop.

[0020] Optionally, the plurality of doped regions include doped regions adjacent to the IGBT region and doped regions spaced apart from the IGBT region, wherein the doped region adjacent to the IGBT region penetrates the collector region of the terminal region in the first direction, the side of the doped region spaced apart from the IGBT region away from the drift region forms at least a portion of the first surface, and the thickness of the doped region spaced apart from the IGBT region in the first direction is less than the thickness of the doped region adjacent to the IGBT region in the first direction.

[0021] The above technical solution has the following advantages and beneficial effects: By setting it up in this way, the amount of carriers injected from the collector region of the terminal area to the drift region can be reduced during the IGBT turn-on process, while the amount of carriers flowing from the collector region of the IGBT area to the drift region of the terminal area can be reduced, thereby reducing the amount of carriers discharged during the turn-off process, further reducing the turn-off loss, while not affecting the IGBT's on-state voltage drop, and can also relatively reduce the amount of dopant used when forming the doped region, thus reducing the manufacturing cost of the device.

[0022] Optionally, the plurality of doped regions include doped regions adjacent to the IGBT region and doped regions spaced apart from the IGBT region, wherein the doped region adjacent to the IGBT region penetrates the collector region of the terminal region in the first direction, and there is a gap between the two surfaces of the doped region spaced apart from the IGBT region and the collector region of the terminal region that are opposite to each other in the first direction.

[0023] The above technical solution has the following advantages and beneficial effects: By setting it up in this way, the amount of carriers injected from the collector region of the terminal area to the drift region can be reduced during the IGBT turn-on process, while the amount of carriers flowing from the collector region of the IGBT area to the drift region of the terminal area can be reduced, thereby reducing the amount of carriers discharged during the turn-off process, further reducing the turn-off loss, while not affecting the IGBT's on-state voltage drop, and can also relatively reduce the amount of dopant used when forming the doped region, thus reducing the manufacturing cost of the device.

[0024] Optionally, the plurality of doped regions extend through the collector region of the terminal region in the first direction.

[0025] The above technical solution has the following advantages and beneficial effects: it can recombine more holes, reduce the amount of holes discharged during the turn-off process, and further reduce turn-off losses.

[0026] Optionally, it also includes:

[0027] An insulating layer is disposed on the second surface and covers the trench gate and a portion of the emission region;

[0028] An emitter metal covers the insulating layer and a portion of the second surface, and the emitter metal is in contact with the emitting region;

[0029] A current collector metal is disposed on the first surface and in contact with the current collector region;

[0030] A contact area of ​​the second conductivity type is disposed alongside the emitter area on the side of the body region facing the second surface. The side of the contact area away from the body region constitutes a portion of the second surface, and the emitter metal is in contact with the contact area.

[0031] The above technical solution has the following advantages and beneficial effects: the insulating layer electrically isolates the emitter region and the trench gate; the emitter metal and collector metal respectively lead out the emitter region and the collector region, thereby facilitating their connection with external circuits; the contact area can improve the current output capability.

[0032] Optionally, the trench gate includes a gate trench extending from the second surface into the drift region, a gate dielectric layer located on the inner surface of the gate trench, and a gate located on the side of the gate dielectric layer away from the inner surface of the gate trench.

[0033] The above technical solution has the following advantages and beneficial effects: the gate dielectric layer plays an isolation role, and the trench gate plays a control role in the IGBT. When the gate voltage is applied to the gate, a conductive channel can be formed around the trench gate, allowing electrons and holes to move in the channel, thereby controlling the conduction and turn-off of the IGBT.

[0034] Optionally, the substrate further includes an FRD region disposed adjacent to the IGBT region, the terminal region being located outside the FRD region, and the FRD region comprising the drift region, the body region, and the trench gate;

[0035] The IGBT structure further includes an injection region of a first conductivity type, which is disposed within the FRD region and arranged 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 at least a portion of the first surface.

[0036] The above technical solution has the following advantages and beneficial effects: The FRD region is the region in the IGBT that plays the role of freewheeling reverse current. The IGBT that integrates the IGBT region and the FRD region is the RC-IGBT. The RC-IGBT has higher integration, smaller junction temperature fluctuation and lower thermal resistance.

[0037] According to a second aspect of this application, a method for manufacturing an IGBT structure is provided, comprising:

[0038] A substrate of a first conductivity type is provided, the substrate including an IGBT region and a terminal region located outside the IGBT region, and the substrate having a first surface and a second surface that are opposite to each other in a first direction;

[0039] A second conductivity type of protective ring and a plurality of spaced trench gates are formed in the terminal region and the IGBT region, respectively, extending from the second surface into the substrate.

[0040] The second surface is subjected to an ion implantation process to form a body region of a second conductivity type and an emitter region of a first conductivity type between adjacent trench gates, wherein the emitter region is disposed on the side of the body region facing the second surface, and the side of the emitter region away from the body region constitutes at least a portion of the second surface;

[0041] The first surface is subjected to an ion implantation process to sequentially form a collector region of a second conductivity type and a plurality of doped regions of a first conductivity type. A drift region is provided between the collector region and the body region, between the collector region and the trench gate, and between the collector region and the guard ring. The collector region is located on the side of the drift region facing the first surface, and the side of the collector region away from the drift region constitutes at least a portion of the first surface. The plurality of doped regions are spaced apart in the collector region of the terminal region along a direction perpendicular to the first direction.

[0042] The above technical solution has the following advantages and beneficial effects: According to the manufacturing method of the IGBT structure in this application, multiple doped regions of the first conductivity type are spaced apart in the collector region of the second conductivity type in the terminal region along a direction perpendicular to the first direction. This can reduce the amount of carriers injected into the drift region of the terminal region by the collector region of the terminal region during the IGBT turn-on process, thereby reducing the amount of carriers discharged during the turn-off process and reducing the turn-off loss. At the same time, it will not affect the on-state voltage drop of the IGBT.

[0043] The semiconductor device according to the embodiments of this application includes the IGBT structure described above.

[0044] The above technical solution has the following advantages and beneficial effects: Since the semiconductor device according to this application includes the aforementioned IGBT structure, it also has the advantages and beneficial effects of the aforementioned IGBT structure. Attached Figure Description

[0045] 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.

[0046] Figures 1A-1G A cross-sectional view of the IGBT structure obtained by sequentially implementing the manufacturing method of the IGBT structure in an embodiment of this application is shown.

[0047] Figure 2 A cross-sectional view of an IGBT structure according to another embodiment of this application is shown.

[0048] Figure 3 A cross-sectional view of an IGBT structure according to another embodiment of this application is shown.

[0049] Figure 4 A cross-sectional view of an IGBT structure according to another embodiment of this application is shown.

[0050] Figure 5 A cross-sectional view of an IGBT structure according to another embodiment of this application is shown.

[0051] Figure 6 A cross-sectional view of an IGBT structure according to another embodiment of this application is shown.

[0052] Figure 7 A flowchart illustrating the manufacturing method of the IGBT structure in an embodiment of this application is shown.

[0053] Figure label:

[0054] 100. Substrate; 101. First surface; 102. Second surface; 110. Drift region; 120. Trench gate; 121. Gate; 122. Gate dielectric layer; 123. Gate trench; 130. Guard ring; 140. Body region; 141. Contact region; 150. Emitter region; 160. Field cutoff region; 170. Collector region; 180. Implantation region; 190. Doped region; 200. Insulating layer; 300. Emitter metal; 400. Collector metal. Detailed Implementation

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] In related technologies, taking the IGBT structure with a P-type collector as an example, during the turn-on process, current flows from the emitter region to the collector region within the IGBT. A portion of this current flows into the termination region, accumulating electrons and holes there. Simultaneously, the collector region in the termination region injects a large number of holes into the drift region, increasing the number of holes accumulated in the termination region. During the IGBT's turn-off process, the number of holes discharged from the termination region increases, leading to greater turn-off losses. Related technologies typically reduce turn-off losses by decreasing hole injection efficiency; however, this method significantly impacts the IGBT's on-state voltage drop.

[0062] like Figures 1G to 6 As shown, in order to solve the above problems, this application provides an IGBT structure, which mainly includes: a substrate 100, a drift region 110 of a first conductivity type, a plurality of trench gates 120, a guard ring 130 of a second conductivity type, a body region 140 of a second conductivity type, an emitter region 150 of a first conductivity type, a collector region 170 of a second conductivity type, and a plurality of doped regions 190 of a first conductivity type.

[0063] 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.

[0064] The substrate 100 includes an IGBT region and a terminal region located outside the IGBT region, i.e., the terminal region surrounds the IGBT region. The IGBT region is the main area in the IGBT responsible for current conduction, and the channel is formed in the IGBT region. The terminal region mainly plays the role of protecting and improving the voltage withstand performance of the IGBT.

[0065] Substrate 100 has in a first direction ( Figures 1A to 6 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.

[0066] 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).

[0067] The drift region 110 is located between the first surface 101 and the second surface. The drift region 110 determines the saturation voltage drop and voltage level of the IGBT and is the main region affecting the switching speed of the IGBT. The conductivity type of the drift region 110 is the first conductivity type.

[0068] Multiple trench gates 120 are spaced apart within the IGBT region and extend from the second surface 102 into the drift region 110. Each trench gate 120 includes a gate trench 123 extending from the second surface 102 into the drift region 110, a gate dielectric layer 122 located on the inner surface of the gate trench 123, and a gate 121 located on the side of the gate dielectric layer 122 away from the inner surface of the gate trench 123. The gate 121 is isolated from the inner surface of the gate trench 123 by the gate dielectric layer 122. Exemplarily, the gate dielectric layer 122 can be a silicon dioxide layer, and the gate 121 can be polysilicon. The side of the trench gate 120 away from the first surface 101 constitutes a portion of the second surface 102. The trench gate 120 configuration creates a more efficient conductive channel, reducing carrier scattering and resistance during transport, thereby lowering the voltage drop in the on-state. A lower on-state voltage drop means that the IGBT has lower power loss and higher efficiency at the same operating current. For example, the trench gate 120 in the IGBT region is an active gate, a gate structure that plays a control role in the IGBT and can form a conductive channel. When a gate voltage is applied to the trench gate 120, a conductive channel can be formed around the trench gate 120, allowing electrons and holes to move in the channel, thereby controlling the IGBT's turn-on and turn-off.

[0069] A second conductive type of guard ring 130 is disposed in the terminal region and extends from the second surface 102 into the drift region 110 to improve the withstand voltage performance of the IGBT structure. Exemplarily, a plurality of guard rings 130 may be formed at intervals.

[0070] The body region 140 (also called the base region) of the second conductivity type is disposed on the side of the drift region 110 facing the second surface 102 and located between adjacent trench gates 120.

[0071] The emitter region 150 of the first conductivity type is disposed on the side of the body region 140 facing the second surface 102, and the side of the emitter region 150 away from the body region 140 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. Exemplarily, the emitter region 150 is located within the IGBT region.

[0072] The collector region 170 of the second conductivity type is disposed on the side of the drift region 110 facing the first surface 101, and the side of the collector region 170 away from the drift region 110 constitutes at least a portion of the first surface 101.

[0073] Multiple doped regions 190 of a first conductivity type are spaced apart in the collector region 170 of the terminal region along a direction perpendicular to the first direction. The doped regions 190 provide free electrons. During IGBT turn-on, the collector region 170 of the terminal region injects holes into the drift region 110 of the terminal region. The free electrons in the doped regions 190 recombine with the holes, thereby reducing the amount of holes injected from the collector region 170 into the drift region 110 of the terminal region. This results in fewer holes being discharged from the drift region 110 during IGBT turn-off, thus reducing the IGBT turn-off loss. The direction perpendicular to the first direction can be the arrangement direction of the multiple trench gates 120 or the extension direction of the trench gates 120. Since the doped regions 190 are located in the collector region 170 of the terminal region, and the collector region 170 of the IGBT region does not contain doped regions 190, it does not affect other parameters such as the IGBT's on-state voltage drop.

[0074] In some examples, the terminal region has a first side close to the IGBT region and a second side opposite to the first side (from... Figures 1G to 6 Viewed from the center, the first side of the terminal area is the left side of the terminal area, and the second side of the terminal area is the right side of the terminal area. Specifically, from the second side of the terminal area to the first side of the terminal area, as shown... Figure 2 As shown, the width of the plurality of doped regions 190 gradually increases in the direction perpendicular to the first direction; and / or, as Figure 3 As shown, the thickness of the multiple doped regions 190 gradually increases in the first direction; and / or, as Figure 4 As shown, the spacing between adjacent doped regions 190 gradually decreases. Through the aforementioned arrangement, from the second side of the terminal region to the first side of the terminal region, the number of free electrons provided by the doped region 190 gradually increases. That is, in the collector region 170 of the terminal region, there are more free electrons near the IGBT region than those far from the IGBT region. This allows the free electrons in the doped region 190 near the IGBT region to recombine with holes in the collector region 170 of the terminal region, while also recombinating with holes flowing into the terminal region from the collector region 170 of the IGBT region. This reduces the amount of holes injected from the collector region 170 of the terminal region into the drift region 110 during IGBT turn-on, while also reducing the amount of holes flowing from the collector region 170 of the IGBT region into the drift region 110 of the terminal region, thereby reducing the amount of holes discharged during turn-off and further reducing turn-off losses.

[0075] In some embodiments, such as Figure 2 As shown, multiple doped regions 190 penetrate the collector region 170 of the terminal region in the first direction, thereby enabling it to recombine more holes, reduce the amount of holes discharged during the turn-off process, and further reduce the turn-off loss.

[0076] In some examples, such as Figure 5As shown, the plurality of doped regions 190 include doped regions 190 adjacent to the IGBT region and doped regions 190 spaced apart from the IGBT region. The doped region 190 adjacent to the IGBT region penetrates the collector region 170 of the terminal region in a first direction. The side of the doped region 190 spaced apart from the IGBT region away from the drift region 110 forms at least a portion of the first surface 101. The thickness of the doped region 190 spaced apart from the IGBT region in the first direction is less than the thickness of the doped region 190 adjacent to the IGBT region in the first direction.

[0077] In some examples, such as Figure 6 As shown, the multiple doped regions 190 include doped regions 190 adjacent to the IGBT region and doped regions 190 spaced apart from the IGBT region. The doped region 190 adjacent to the IGBT region penetrates the collector region 170 of the terminal region in the first direction. There is a gap between the two surfaces of the doped region 190 spaced apart from the IGBT region and the collector region 170 of the terminal region that are opposite to each other in the first direction.

[0078] By using the two configuration methods described above, the amount of free electrons in the doped region 190 adjacent to the IGBT region can be increased. This allows the free electrons in the doped region 190 adjacent to the IGBT region to recombine with the holes in the collector region 170 of the terminal region, while simultaneously recombinating with the holes flowing into the terminal region from the collector region 170 of the IGBT region. This reduces the amount of holes injected from the collector region 170 of the terminal region into the drift region 110 during IGBT turn-on, while also reducing the amount of holes flowing into the drift region 110 of the terminal region from the collector region 170 of the IGBT region. This reduces the amount of holes discharged during turn-off, further reducing turn-off losses. Furthermore, it can relatively reduce the amount of dopant used during the formation of the doped region, thereby reducing the manufacturing cost of the device.

[0079] like Figures 1G to 6 As shown, the IGBT structure further includes: an insulating layer 200, an emitter metal 300, a collector metal 400, and a contact area 141 of a second conductivity type.

[0080] An insulating layer 200 is disposed on the second surface 102 and covers the trench gate 120 and a portion of the emitter region 150. An emitter metal 300 covers the insulating layer 200 and a portion of the second surface 102, and the emitter metal 300 contacts the emitter region 150 to form a conductive connection, thereby enabling the emitter region 150 to be led out. A collector metal 400 is disposed on the first surface 101 and contacts the collector region 170 to form a conductive connection, thereby enabling the collector region 170 to be led out. The insulating layer 200 has a contact hole corresponding to the portion of the emitter region 150, with a portion of the emitter region 150 exposed at the bottom of the contact hole, through which the emitter metal 300 contacts the emitter region 150. Optionally, the material of the insulating layer 200 may include silicon oxide, silicon nitride, or any other suitable insulating material. By providing the insulating layer 200, the emitter metal 300 and the trench gate 120 can be electrically isolated. For example, the insulating layer 200 also exposes at least a portion of the surface of the protective ring 130, and the emitter metal 300 is in contact with the protective ring 130.

[0081] Contact region 141 and emitter region 150 are disposed side-by-side on the side of body region 140 facing the second surface 102. The side of contact region 141 away from body region 140 constitutes a portion of the second surface 102. Emitter metal 300 contacts contact region 141. The doping concentration of contact region 141 is higher than that of body region 140. By simultaneously providing emitter region 150 of the first conductivity type and contact region 141 of the second conductivity type, the current output capability of IGBT device is effectively improved. Exemplarily, contact region 141 is located within IGBT region.

[0082] like Figures 1G to 6 As shown, the IGBT structure further includes a field-stop region 160 of the first conductivity type, located between the drift region 110 and the collector region 170. The doping concentration of the field-stop region 160 is higher than that of the drift region 110. The main function of the field-stop region 160 is to terminate the electric field in the IGBT's off-state, preventing the electric field from penetrating to the collector region 170, thereby improving the device's withstand voltage capability. When a high voltage is applied, the field-stop region 160 can withstand a portion of the electric field, causing the electric field to gradually weaken before reaching the collector region 170, thus preventing breakdown in the collector region 170. The field-stop region 160 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 lower turn-off losses.

[0083] In some embodiments, the field cutoff region 160 may not be provided in the IGBT structure, and the drift region 110 is in direct contact with the collector region 170 on the side facing the first main surface 101.

[0084] Please continue to refer to Figures 1G to 6The substrate 100 also includes an FRD (Fast Recovery Diode) region adjacent to the IGBT region. The termination region is located outside the FRD region, meaning the termination region surrounds both the IGBT and FRD regions. The FRD region is the area in the IGBT that provides freewheeling reverse current. An IGBT integrating both the IGBT and FRD regions is an RC-IGBT (Reverse Conducting IGBT). Compared to an IGBT without an integrated FRD region, the RC-IGBT has higher integration density, smaller junction temperature fluctuations, and lower thermal resistance. Exemplarily, the FRD region includes a drift region 110, a trench gate 120, and a body region 140. The body region 140 in the FRD region acts as the anode of the diode. Exemplarily, the emitter metal 200 is also in contact with the body region 140 in the FRD region.

[0085] like Figures 1G to 6 As shown, the IGBT structure also includes an injection region 180 of a first conductivity type. The injection region 180 is disposed within the FRD region and is arranged parallel to the collector region 170 on the side of the drift region 110 facing the first surface. The side of the injection region 180 away from the drift region 110 forms at least a portion of the first surface 101. Exemplarily, the injection region 180 acts as the cathode of the diode. Exemplarily, the doped region 190 and the injection region 180 have the same doping concentration. Exemplarily, the collector metal 400 is also in contact with the injection region 180. Exemplarily, a field-stop region 160 is also disposed between the injection region 180 and the drift region 110.

[0086] In the IGBT structure of this application embodiment, multiple doped regions of the first conductivity type are spaced apart in the collector region of the second conductivity type in the terminal region along a direction perpendicular to the first direction. This can reduce the amount of carriers injected from the collector region of the terminal region into the drift region of the terminal region during the IGBT turn-on process, thereby reducing the amount of carriers discharged during the turn-off process and reducing turn-off losses, while not affecting the on-state voltage drop of the IGBT.

[0087] This application also provides a method for manufacturing an IGBT structure, which is used to manufacture the IGBT structure described above, as follows (see below). Figures 1A-1G , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6 as well as Figure 7 A method for manufacturing an IGBT structure according to an embodiment of this application is described exemplarily.

[0088] First, execute step S1, as follows: Figure 1AAs shown, a substrate 100 of a first conductivity type is provided. The substrate 100 includes an IGBT region and a terminal region located outside the IGBT region, and the substrate 100 has a first orientation ( Figures 1A to 6 The first surface 101 and the second surface 102 are mutually opposed in the vertical direction. Exemplarily, the substrate 100 is used as the drift region 110.

[0089] like Figure 1A As shown, the substrate 100 also includes an FRD region adjacent to the IGBT region, and the terminal region is located outside the FRD region, that is, the terminal region surrounds the IGBT region and the FRD region. The IGBT that integrates the IGBT region and the FRD region is an RC-IGBT.

[0090] Next, step S2 is performed, forming a second conductivity type guard ring 130 extending from the second surface 102 into the substrate 100 and a plurality of spaced trench gates 120 in the terminal region and the IGBT region, respectively. Exemplarily, the second conductivity type guard ring 130 can be formed by an ion implantation process. Exemplarily, the trench gates 120 are also located within the FRD region.

[0091] The trench gate 120 includes a gate trench 123 extending from the second surface 102 into the drift region 110, a gate dielectric layer 122 located on the inner surface of the gate trench 123, and a gate 121 located on the side of the gate dielectric layer 122 away from the inner surface of the gate trench 123. The gate 121 is isolated from the inner surface of the gate trench 123 by the gate dielectric layer 122. The trench gate 120, extending from the second surface 102 into the substrate 100, is formed in the active region, including: firstly, as... Figure 1B As shown, a portion of the substrate 100 is etched from the second surface 102 to form a plurality of gate trenches 123, and a gate dielectric layer 122, such as silicon oxide or other suitable dielectric layer, is formed on the sidewalls and bottom of the gate trenches 123; then, as Figure 1C As shown, a gate 121 is deposited in the gate trench 123 to form a trench gate 120. The gate 121 fills the gate trench 123. The material of the gate 121 can be, for example, polysilicon or other materials suitable as gates.

[0092] Next, step S3 is performed to perform an ion implantation process on the second surface 102 to form a body region 140 of a second conductivity type and an emitter region 150 of a first conductivity type between adjacent trench gates 120. The emitter region 150 is disposed on the side of the body region 140 facing the second surface 102, and the side of the emitter region 150 away from the body region 140 constitutes at least a portion of the second surface 102. Exemplarily, the emitter region 150 is located within the IGBT region.

[0093] After forming the body region 140 of the second conductivity type and the emitter region 150 of the first conductivity type, as Figure 1D and Figure 1E As shown, it also includes the following steps: Figure 1D As shown, an insulating layer 200 and a contact area 141 located within the IGBT region are formed. The insulating layer 200 is disposed on the second surface 102 and covers the trench gate 120 and a portion of the emitter area 150. The contact area 141 is disposed side-by-side with the emitter area 150 on the side of the body region 140 facing the second surface 102. The side of the contact area 141 away from the body region 140 constitutes a portion of the second surface 102. Figure 1E As shown, an emitter metal 300 is formed, which covers the insulating layer 200 and a portion of the second surface 102. The emitter metal 300 contacts the emitter region 150 and the contact region 141. Exemplarily, the insulating layer 200 also exposes at least a portion of the surface of the guard ring 130, and the emitter metal 300 contacts the guard ring 130. Exemplarily, the emitter metal 300 also contacts the body region 140 within the FRD region.

[0094] Next, step S4 is executed to perform an ion implantation process on the first surface 101 to sequentially form a collector region 170 of the second conductivity type and a plurality of doped regions 190 of the first conductivity type. A drift region 110 is provided between the collector region 170 and the body region 140, between the collector region 170 and the trench gate 120, and between the collector region 170 and the guard ring 130. The collector region 170 is located on the side of the drift region 110 facing the first surface 101, and the side of the collector region 170 away from the drift region 110 constitutes at least a portion of the first surface 101. The plurality of doped regions 190 are spaced apart in the collector region 170 of the terminal region along a direction perpendicular to the first direction. Specifically, as shown... Figure 1F As shown, a collector region 170 of the second conductivity type is first formed. This process may also include forming a field-stop region 160 of the first conductivity type using an ion implantation process. The field-stop region 160 is located between the collector region 170 and the drift region 110. Then, as... Figure 1G As shown, a plurality of doped regions 190 of the first conductivity type are formed in the collector region 170 of the terminal region. This process may also include the step of forming an implantation region 180 of the first conductivity type in the FRD region by an ion implantation process. The implantation region 180 is disposed in the FRD region and is disposed in parallel with the collector region 170 on the side of the drift region 110 facing the first surface. The side of the implantation region 180 away from the drift region 110 constitutes at least a portion of the first surface 101.

[0095] Multiple doped regions 190 of a first conductivity type are spaced apart in the collector region 170 of the terminal region along a direction perpendicular to the first direction. The doped regions 190 provide free electrons. During IGBT turn-on, the collector region 170 of the terminal region injects holes into the drift region 110 of the terminal region. The free electrons in the doped regions 190 recombine with the holes, thereby reducing the amount of holes injected from the collector region 170 into the drift region 110 of the terminal region. This results in fewer holes being discharged from the drift region 110 during IGBT turn-off, thus reducing the IGBT turn-off loss. The direction perpendicular to the first direction can be the arrangement direction of the multiple trench gates 120 or the extension direction of the trench gates 120. Since the doped regions 190 are located in the collector region 170 of the terminal region, and the collector region 170 of the IGBT region does not contain doped regions 190, it does not affect other parameters such as the IGBT's on-state voltage drop.

[0096] After forming the doped region 190, as Figure 1G As shown, the method also includes the step of forming a collector metal 400, which is disposed on the first surface 101 and contacts the collector region 170 to form a conductive connection, thereby enabling the collector region 170 to be led out. Exemplarily, the collector metal 400 also contacts the injection region 180.

[0097] The manufacturing method of the IGBT structure in this application embodiment involves multiple doped regions of the first conductivity type being spaced apart in the collector region of the second conductivity type in the terminal region along a direction perpendicular to the first direction. This reduces the amount of carriers injected into the drift region of the terminal region by the collector region during the IGBT turn-on process, thereby reducing the amount of carriers discharged during the turn-off process and reducing turn-off losses, without affecting the on-state voltage drop of the IGBT.

[0098] This application also provides a semiconductor device comprising the IGBT structure described above. This semiconductor device can be a power semiconductor device.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] 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 IGBT structure, characterized in that, include: The substrate includes an IGBT region and a terminal region located outside the IGBT region, and the substrate has a first surface and a second surface that are opposite to each other in a first direction; A drift region of a first conductivity type is disposed between the first surface and the second surface; Multiple trench gates are spaced apart within the IGBT region and extend from the second surface into the drift region; A body region of the second conductivity type is disposed on the side of the drift region facing the second surface and located between adjacent trench gates; An emitting region of a first conductivity type is disposed on the side of the body region facing the second surface, and the side of the emitting region away from the body region constitutes at least a portion of the second surface; A second conductive type of protective ring is disposed in the terminal region and extends from the second surface into the drift region; A collector region of a second conductivity type is disposed on the side of the drift region facing the first surface, and the side of the collector region away from the drift region constitutes at least a portion of the first surface; Multiple doped regions of a first conductivity type are spaced apart in the collector region of the terminal region along a direction perpendicular to the first direction. The terminal region has a first side close to the IGBT region and a second side opposite to the first side. From the second side to the first side, the width of the multiple doped regions gradually increases in the direction perpendicular to the first direction; and / or the thickness of the multiple doped regions gradually increases in the first direction; and / or the spacing between adjacent doped regions gradually decreases.

2. The IGBT structure according to claim 1, characterized in that, The plurality of doped regions include doped regions adjacent to the IGBT region and doped regions spaced apart from the IGBT region, wherein the doped region adjacent to the IGBT region penetrates the collector region of the terminal region in the first direction, the side of the doped region spaced apart from the IGBT region away from the drift region forms at least a portion of the first surface, and the thickness of the doped region spaced apart from the IGBT region in the first direction is less than the thickness of the doped region adjacent to the IGBT region in the first direction.

3. The IGBT structure according to claim 1, characterized in that, The plurality of doped regions include doped regions adjacent to the IGBT region and doped regions spaced apart from the IGBT region. The doped region adjacent to the IGBT region penetrates the collector region of the terminal region in the first direction. There is a gap between the two surfaces of the doped region spaced apart from the IGBT region and the collector region of the terminal region, which are opposite to each other in the first direction.

4. The IGBT structure according to claim 1, characterized in that, The plurality of doped regions penetrate the collector region of the terminal region in the first direction.

5. The IGBT structure according to any one of claims 1-4, characterized in that, Also includes: An insulating layer is disposed on the second surface and covers the trench gate and a portion of the emission region; An emitter metal covers the insulating layer and a portion of the second surface, and the emitter metal is in contact with the emitting region; A current collector metal is disposed on the first surface and in contact with the current collector region; A contact area of ​​the second conductivity type is disposed alongside the emitter area on the side of the body region facing the second surface. The side of the contact area away from the body region constitutes a portion of the second surface, and the emitter metal is in contact with the contact area.

6. The IGBT structure according to any one of claims 1-4, characterized in that, The trench gate includes a gate trench extending from the second surface into the drift region, a gate dielectric layer located on the inner surface of the gate trench, and a gate located on the side of the gate dielectric layer away from the inner surface of the gate trench.

7. The IGBT structure according to any one of claims 1-4, characterized in that, The substrate further includes an FRD region disposed adjacent to the IGBT region, the terminal region being located outside the FRD region, and the FRD region comprising the drift region, the body region, and the trench gate. The IGBT structure further includes an injection region of a first conductivity type, which is disposed within the FRD region and is arranged 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 at least a portion of the first surface.

8. A method for manufacturing an IGBT structure, characterized in that, include: A substrate of a first conductivity type is provided, the substrate including an IGBT region and a terminal region located outside the IGBT region, and the substrate having a first surface and a second surface that are opposite to each other in a first direction; A second conductivity type of protective ring and a plurality of spaced trench gates are formed in the terminal region and the IGBT region, respectively, extending from the second surface into the substrate. The second surface is subjected to an ion implantation process to form a body region of a second conductivity type and an emitter region of a first conductivity type between adjacent trench gates, wherein the emitter region is disposed on the side of the body region facing the second surface, and the side of the emitter region away from the body region constitutes at least a portion of the second surface; The first surface is subjected to an ion implantation process to sequentially form a collector region of a second conductivity type and a plurality of doped regions of a first conductivity type. A drift region is provided between the collector region and the body region, between the collector region and the trench gate, and between the collector region and the guard ring. The collector region is located on the side of the drift region facing the first surface, and the side of the collector region away from the drift region constitutes at least a portion of the first surface. The plurality of doped regions are spaced apart in the collector region of the terminal region along a direction perpendicular to the first direction. The terminal region has a first side close to the IGBT region and a second side opposite to the first side. From the second side to the first side, the width of the plurality of doped regions gradually increases in the direction perpendicular to the first direction; and / or the thickness of the plurality of doped regions gradually increases in the first direction; and / or the spacing between adjacent doped regions gradually decreases.

9. A semiconductor device, characterized in that, The IGBT structure includes any one of claims 1-7.

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