IGBT (Insulated Gate Bipolar Translator) structure, manufacturing method thereof and semiconductor device

Abstract

The invention discloses an IGBT structure and a manufacturing method thereof, and a semiconductor device, and the IGBT structure comprises a substrate, a drift region of a first conduction type, a field cut-off region of the first conduction type, a collector region of a second conduction type, a plurality of trench gates, a body region of the second conduction type, an emitter region of the first conduction type, and a protection ring of the first conduction type. The substrate comprises an active region and a terminal region located on the outer side of the active region, the field cut-off region is arranged on the side, facing the first surface, of the drift region, the collector region is arranged on the side, facing the first surface, of the field cut-off region, and the field cut-off region comprises a first field cut-off region located in the active region and a second field cut-off region located in the terminal region; and the doping concentration of at least partial region of the second field stop region is greater than that of the first field stop region. According to the IGBT structure, the manufacturing method thereof and the semiconductor device, the turn-off loss can be effectively reduced, and the conduction voltage drop cannot be influenced.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductors, and in particular to an IGBT structure and a manufacturing method thereof, and a semiconductor device. Background Art

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

[0003] In the related art, the IGBT includes an active area and a terminal area located outside the active area. A guard ring is formed in the terminal area to ensure voltage resistance. During the IGBT turn-on process, taking the collector area and the emitter area as P-type conductive type as an example, a large number of holes will accumulate in the terminal area, resulting in an increase in the number of holes that need to be discharged from the terminal area during the IGBT turn-off process, which increases the turn-off loss.

[0004] Improvements are therefore needed to at least partially address the above-mentioned problems. Summary of the invention

[0005] A series of simplified concepts are introduced in the Summary of the Invention section, which will be further described in detail in the Detailed Description of the Invention section. The Summary of the Invention section of this application does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the scope of protection of the claimed technical solution.

[0006] In order to at least partially solve the above problems, according to a first aspect of the present application, an IGBT structure is provided, comprising:

[0007] A substrate, comprising an active region and a terminal region located outside the active region, and the substrate has a first surface and a second surface facing away from each other in a first direction;

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

[0009] A field stop region of a first conductivity type, disposed on a side of the drift region facing the first surface;

[0010] A collector region of a second conductivity type is disposed on a side of the field stop region facing the first surface, and a side of the collector region away from the field stop region constitutes at least a portion of the first surface;

[0011] A plurality of trench gates are spaced apart in the active region and extend from the second surface to the drift region;

[0012] A body region of the second conductivity type, disposed on a side of the drift region facing the second surface and located between adjacent trench gates;

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

[0014] A guard ring of a first conductivity type is disposed in the terminal region and extends from the second surface into the drift region;

[0015] The field stop region includes a first field stop region located in the active region and a second field stop region located in the terminal region, and the doping concentration of at least a portion of the second field stop region is greater than the doping concentration of the first field stop region.

[0016] The above technical solution has the following advantages and beneficial effects: According to the IGBT structure in the present application, the doping concentration of at least part of the second field stop region located in the terminal region is greater than the doping concentration of the first field stop region located in the active region. Therefore, it is possible to reduce the amount of carriers injected into the drift region from 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, reducing the turn-off loss, and at the same time will not affect the on-state voltage drop of the IGBT.

[0017] Optionally, the first field stop region has a first doping concentration, the second field stop region has a second doping concentration, and the second doping concentration is less than the first doping concentration; or

[0018] The first field stop region has the first doping concentration, and the second field stop region includes a first region having the first doping concentration and a second region having the second doping concentration.

[0019] The above technical solution has the following advantages and beneficial effects: by making the doping concentration of the entire area or part of the area of ​​the second field stop region greater than the doping concentration of the first field stop region located in the active area, the amount of carriers injected into the drift region by the collector region of the terminal region during the IGBT turn-on process can be reduced, thereby reducing the amount of carriers discharged during the turn-off process, reducing the turn-off loss, and at the same time will not affect the on-state voltage drop of the IGBT.

[0020] Optionally, the second field stop region includes at least one first region and at least one second region, and the first region and the second region are arranged along a direction perpendicular to the first direction or along the first direction.

[0021] The above technical solution has the following advantages and beneficial effects: through such a setting method, the amount of carriers injected into the drift region by the collector region of the terminal region during the IGBT turn-on process can be reduced, thereby reducing the amount of carriers discharged during the turn-off process and reducing the turn-off loss, while also not affecting the on-state voltage drop of the IGBT.

[0022] Optionally, the second doping concentration is 1.5-2.5 times the first doping concentration.

[0023] The above technical solution has the following advantages and beneficial effects: through such a setting method, the amount of carriers injected into the drift region by the collector region of the terminal region during the IGBT turn-on process can be reduced, thereby reducing the amount of carriers discharged during the turn-off process and reducing the turn-off loss, while also not affecting the on-state voltage drop of the IGBT.

[0024] Optionally, it also includes:

[0025] An insulating layer, disposed on the second surface and covering the trench gate and a portion of the emitter region;

[0026] An emitter metal covers the insulating layer and a portion of the second surface, and the emitter metal contacts the emitter region.

[0027] The above technical solution has the following advantages and beneficial effects: the emitter region and the trench gate are electrically isolated by the insulating layer, and the emitter metal leads out the emitter region, thereby facilitating its connection with the external circuit.

[0028] Optionally, a contact region of a second conductivity type is further included, wherein the contact region and the emitter region are arranged in parallel on a side of the body region facing the second surface, a side of the contact region away from the body region constitutes part of the second surface, and the emitter metal contacts the contact region.

[0029] The above technical solution has the following advantages and beneficial effects: by setting the contact area, the current output capacity can be improved.

[0030] Optionally, a collector metal is further included, wherein the collector metal is disposed on the first surface and in contact with the collector region.

[0031] The above technical solution has the following advantages and beneficial effects: the emitter metal can lead out the collector, thereby facilitating its connection with an external circuit.

[0032] Optionally, the trench gate includes a gate trench extending from the second surface to the drift region, a gate dielectric layer located on an inner surface of the gate trench, and a gate located on a 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, the trench gate plays a control role in the IGBT, and 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 on and off of the IGBT.

[0034] According to a second aspect of the present application, a method for manufacturing an IGBT structure is provided, comprising:

[0035] Providing a substrate of a first conductivity type, the substrate comprising an active region and a terminal region located outside the active region, and the substrate having a first surface and a second surface facing away from each other in a first direction;

[0036] forming a first conductive type guard ring and a plurality of intervally arranged trench gates extending from the second surface into the substrate in the terminal region and the active region respectively;

[0037] Performing an ion implantation process on the second surface to form a body region of the second conductivity type and an emitter region of the first conductivity type between adjacent trench gates, wherein the emitter region is arranged on a side of the body region facing the second surface, and a side of the emitter region away from the body region constitutes at least a portion of the second surface;

[0038] An ion implantation process is performed on the first surface to form a field stop region of a first conductivity type and a collector region of a second conductivity type, a drift region is arranged between the field stop region and the body region, the trench gate and the guard ring, the collector region is arranged on a side of the field stop region facing the first surface, and a side of the collector region away from the field stop region constitutes at least a portion of the first surface, wherein the field stop region includes a first field stop region located in the active region and a second field stop region located in the terminal region, and the doping concentration of at least a portion of the second field stop region is greater than the doping concentration of the first field stop region.

[0039] The above technical solution has the following advantages and beneficial effects: According to the manufacturing method of the IGBT structure in the present application, the doping concentration of at least a part of the second field stop region located in the terminal region is greater than the doping concentration of the first field stop region located in the active region, thereby reducing the amount of carriers injected into the drift region from 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, reducing the turn-off loss, and at the same time will not affect the on-state voltage drop of the IGBT.

[0040] The semiconductor device according to the embodiment of the present application includes the above-mentioned IGBT structure.

[0041] The above technical solution has the following advantages and beneficial effects: Since the semiconductor device in the present application includes the above-mentioned IGBT structure, it also has the advantages and beneficial effects of the above-mentioned IGBT structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] By describing the embodiments of the present application in more detail in conjunction with the accompanying drawings, the above and other purposes, features and advantages of the present application will become more apparent. The accompanying drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the present application and do not constitute a limitation of the present application. In the accompanying drawings, the same reference numerals generally represent the same components or steps.

[0043] Figure 1A-1G A cross-sectional view of an IGBT structure obtained by sequentially implementing the method for manufacturing the IGBT structure in an embodiment of the present application is shown.

[0044] Figure 2 A cross-sectional view of an IGBT structure in another embodiment of the present application is shown.

[0045] Figure 3 A cross-sectional view of an IGBT structure in another embodiment of the present application is shown.

[0046] Figure 4 A flow chart showing a method for manufacturing an IGBT structure in an embodiment of the present application is shown.

[0047] Reference numerals:

[0048] 100, substrate; 101, first surface; 102, second surface; 110, drift region; 120, field stop region; 121, first field stop region; 122, second field stop region; 1221, first region; 1222, second region; 130, collector region; 140, trench gate; 141, gate; 142, gate dielectric layer; 143, gate trench; 150, body region; 160, emitter region; 170, contact region; 180, guard ring; 200, insulating layer; 300, emitter metal; 400, collector metal. DETAILED DESCRIPTION

[0049] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present application. However, it is apparent to those skilled in the art that the present application can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present application, some technical features well known in the art are not described.

[0050] It should be understood that the present application can be implemented in different forms and should not be construed as being limited to the embodiments presented herein. On the contrary, providing these embodiments will make the disclosure thorough and complete and fully convey the scope of the present application to those skilled in the art. In the accompanying drawings, the sizes and relative sizes of layers and regions may be exaggerated for clarity. The same reference numerals throughout represent the same elements.

[0051] It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present application, the first element, component, region, layer or part discussed below can be represented as a second element, component, region, layer or part.

[0052] Spatially relative terms such as "under", "beneath", "below", "under", "above", "above", etc., may be used herein for convenience of description to describe the relationship of one element or feature to other elements or features shown in the figures. It should be understood that the spatially relative terms are intended to encompass different orientations of the device in use and operation in addition to the orientation shown in the figures.

[0053] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be limiting of the present application. When used herein, the singular forms "one", "an" and "said / the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0054] Embodiments of the application are described herein with reference to cross-sectional views as schematic diagrams of ideal embodiments (and intermediate structures) of the application. In this way, variations in the shapes shown due to, for example, manufacturing techniques and / or tolerances can be 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. Therefore, what is shown in the figures is schematic in nature, and their shapes are not intended to display the actual shapes of the devices and are not intended to limit the scope of the application.

[0055] In the IGBT structure in the related art, taking the collector and emitter regions as P-type conductivity types as an example, during the turn-on process, current flows from the emitter region to the collector region in the active region, and part of the current will flow into the terminal region, thereby accumulating electrons and holes in the terminal region, and the collector region of the terminal region will also inject a large number of holes into the drift region, making the number of holes accumulated in the terminal region more. During the IGBT's turn-off process, the number of holes discharged from the terminal region will increase, resulting in greater turn-off losses. In the related art, the turn-off loss is generally reduced by reducing the hole injection efficiency, but the general method of reducing the hole injection efficiency will greatly affect the on-state voltage drop of the IGBT.

[0056] like Figure 1G , Figure 2 as well as Figure 3 As shown, in order to solve the above problems, an embodiment of the present application provides an IGBT structure, which mainly includes: a substrate 100, a drift region 110 of a first conductive type, a field stop region 120 of a first conductive type, a collector region 130 of a second conductive type, a plurality of trench gates 140, a body region 150 of a second conductive type, an emitter region 160 of a first conductive type and a guard ring 180 of a first conductive type.

[0057] First, it should be noted that, in this article, N and P represent the conductivity type of the semiconductor. In the following, the first conductivity type is set to N type and the second conductivity type is set to P type for description.

[0058] The substrate 100 includes an active area and a terminal area outside the active area, that is, the terminal area surrounds the active area, wherein the active area is the main area responsible for current conduction in the IGBT, and the channel is formed in the active area; the terminal area mainly plays a role in protecting and improving the voltage resistance performance of the IGBT.

[0059] The substrate 100 has a first direction ( Figures 1A to 1G The first surface 101 and the second surface 102 are separated from each other in the up-down direction (in the vertical direction), and the first surface 101 and the second surface 102 are spaced apart along the first direction.

[0060] Exemplarily, 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 a multilayer structure composed of these semiconductor materials, or silicon on insulator (SOI), stacked silicon on insulator (SSOI), stacked silicon germanium on insulator (S-SiGeOI), silicon germanium on insulator (SiGeOI) and germanium on insulator (GeOI).

[0061] The drift region 110 is disposed 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 that affects the switching speed of the IGBT. The conductivity type of the drift region 110 is the first conductivity type.

[0062] The field stop region 120 of the first conductivity type is arranged on the side of the drift region 110 facing the first surface 101, and the doping concentration of the field stop region 120 is higher than that of the drift region 110. The main function of the field stop region 120 is to terminate the electric field when the IGBT is turned off, to prevent the electric field from penetrating into the collector region 130, thereby improving the voltage resistance of the device. When a high voltage is applied, the field stop region 120 can withstand a part of the electric field, so that the electric field gradually weakens before reaching the collector region 130, limiting the breakdown of the collector region 130. The field stop region 120 can also reduce the duration and amplitude of the tail current by adjusting the carrier distribution and extraction speed. The reduction of the tail current helps to reduce the turn-off loss.

[0063] The collector region 130 of the second conductivity type is disposed on a side of the field stop region 120 facing the first surface 101 , and a side of the collector region 130 away from the field stop region 120 constitutes at least a portion of the first surface 101 .

[0064] A plurality of trench gates 140 are arranged at intervals in the active region and extend from the second surface 102 to the drift region 110. The trench gate 140 includes a gate trench 143 extending from the second surface 102 to the drift region 110, a gate dielectric layer 142 located on the inner surface of the gate trench 143, and a gate 141 located on the side of the gate dielectric layer 142 away from the inner surface of the gate trench 143, and the gate 141 is isolated from the inner surface of the gate trench 143 by the gate dielectric layer 142. Exemplarily, the gate dielectric layer 142 may be a silicon dioxide layer, and the gate 141 may be polysilicon. The side of the trench gate 140 away from the first surface 101 constitutes part of the second surface 102. The arrangement of the trench gate 140 can form a more effective conductive channel, reduce the scattering and resistance of carriers during transmission, and thereby reduce the voltage drop in the on state. A lower on-state voltage drop means that at the same operating current, the IGBT has a smaller power loss and higher efficiency. Exemplarily, the trench gate 140 is an active gate, which plays a control role in the IGBT and is a gate structure capable of forming a conductive channel. When a gate voltage is applied to the trench gate 140, a conductive channel can be formed around the trench gate 140, so that electrons and holes can move in the channel, thereby controlling the on and off of the IGBT.

[0065] The body region 150 of the second conductivity type (also referred to as the base region) is disposed on the side of the drift region 110 facing the second surface 102 and is located between adjacent trench gates 140 .

[0066] The emitter region 160 of the first conductivity type is disposed on the side of the body region 150 facing the second surface 102, and the side of the emitter region 160 away from the body region 150 constitutes a portion of the second surface 102. The doping concentration of the emitter region 160 of the first conductivity type is higher than the doping concentration of the drift region 110.

[0067] The first conductive type guard ring 180 is disposed in the terminal region and extends from the second surface 102 to the drift region 110 to improve the withstand voltage performance of the IGBT structure. Exemplarily, a plurality of guard rings 180 disposed at intervals may be formed.

[0068] The field stop region 120 includes a first field stop region 121 located in the active region and a second field stop region 122 located in the terminal region. The doping concentration of at least a portion of the second field stop region 122 is greater than the doping concentration of the first field stop region 121 . By making the doping concentration of at least part of the second field stop region 122 greater than the doping concentration of the first field stop region 121, the free electrons in the second field stop region 122 located in the terminal region can be increased. During the IGBT turn-on process, the collector region 130 of the terminal region will inject holes into the drift region, and the free electrons in the second field stop region 122 can recombine with the holes. By increasing the free electrons in the second field stop region 122, the second field stop region 122 can recombine more holes from the collector region 130 during the IGBT turn-on process, thereby reducing the amount of holes reaching the drift region 110 through the second field stop region 122, that is, the amount of holes injected from the collector region 130 of the terminal region to the drift region 110 during the IGBT turn-on process can be reduced, so that the holes discharged from the drift region 110 during the IGBT turn-off process are reduced, thereby reducing the turn-off loss of the IGBT. At the same time, the doping concentration of the first field stop region 121 located in the active region in the IGBT structure of the present application does not change, thereby not affecting other parameters such as the on-state voltage drop of the IGBT.

[0069] In some examples, such as Figure 1G As shown, the first field stop region 121 has a first doping concentration, and the second field stop region 122 has a second doping concentration, and the second doping concentration is greater than the first doping concentration; or Figure 2 and Figure 3 As shown, the first field stop region 121 has a first doping concentration, and the second field stop region 122 includes a first region 1221 having the first doping concentration and a second region 1222 having the second doping concentration. The second field stop region 122 may include at least one first region 1221 and at least one second region 1222, and the first region 1221 and the second region 1222 are arranged along a direction perpendicular to the first direction (such as Figure 2 ) or along a first direction (as shown Figure 3The second field stop region 122 is arranged in a direction perpendicular to the first direction, wherein the direction perpendicular to the first direction may be the arrangement direction of the plurality of trench gates 140 or the extension direction of the trench gates 140. By making the doping concentration of all or part of the second field stop region 122 greater than the doping concentration of the first field stop region 121, the second field stop region 122 can recombine more holes from the collector region 130 during the IGBT turn-on process, thereby reducing the amount of holes reaching the drift region 110 through the second field stop region 122, that is, it can reduce the amount of holes injected from the collector region 130 of the terminal region to the drift region 110 during the IGBT turn-on process, so that fewer holes are discharged from the drift region 110 during the IGBT turn-off process, thereby reducing the turn-off loss of the IGBT. Exemplarily, the second doping concentration is 1.5-2.5 times the first doping concentration, or other suitable doping concentration ranges. In one example, the number of the first region 1221 and the second region 1222 can be multiple.

[0070] Please continue to refer to Figure 1G Furthermore, the IGBT structure also includes: an insulating layer 200 and an emitter metal 300 .

[0071] The insulating layer 200 is disposed on the second surface 102 and covers the trench gate 140 and a portion of the emitter region 160. The 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 160 to form a conductive connection to achieve the extraction of the emitter region 160. A contact hole is provided in the portion of the insulating layer 200 corresponding to the emitter region 160, and a portion of the emitter region 160 is exposed at the bottom of the contact hole, and the emitter metal 300 contacts the emitter region 160 through the contact hole. 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 140 can be electrically isolated. Exemplarily, the insulating layer 200 also exposes at least a portion of the surface of the guard ring 180, and the emitter metal 300 contacts the guard ring 180.

[0072] like Figure 1G As shown, the IGBT structure further includes a collector metal 400 , which is disposed on the first surface 101 and in contact with the collector region 130 to form a conductive connection so as to lead out the collector region 130 .

[0073] like Figure 1GAs shown, further, the IGBT structure further includes a contact region 170 of the second conductivity type, the contact region 170 and the emitter region 160 are arranged in parallel on the side of the body region 150 facing the second surface 102, the side of the contact region 170 away from the body region 150 constitutes a part of the second surface 102, and the emitter metal 300 is in contact with the contact region 170. The doping concentration of the contact region 170 is higher than the doping concentration of the body region 150. By simultaneously providing the emitter region 160 of the first conductivity type and the contact region 170 of the second conductivity type, the current output capacity of the IGBT device is effectively improved.

[0074] In the IGBT structure of the embodiment of the present application, the doping concentration of at least a part of the second field stop region located in the terminal region is greater than the doping concentration of the first field stop region located in the active region. Therefore, it is possible to reduce the amount of carriers injected into the drift region from 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, without affecting the on-state voltage drop of the IGBT.

[0075] The present application also provides a method for manufacturing an IGBT structure. The method is used to manufacture the IGBT structure described above. Figure 1A-1G , Figure 2 , Figure 3 as well as Figure 4 A method for manufacturing an IGBT structure according to an embodiment of the present application is exemplified.

[0076] First, execute step S1, such as Figure 1A As shown, a substrate 100 of a first conductive type is provided, the substrate 100 includes an active region and a terminal region located outside the active region, and the substrate 100 has a first direction ( Figures 1A to 1G The substrate 100 includes a first surface 101 and a second surface 102 which are opposite to each other in the vertical direction (in the vertical direction). Exemplarily, the substrate 100 is used as the drift region 110.

[0077] Next, execute step S2, such as Figure 1B and Figure 1C As shown, a first conductive type guard ring 180 and a plurality of spaced trench gates 140 extending from the second surface 102 to the substrate 100 (i.e., extending to the drift region 110) are formed in the terminal region and the active region, respectively. Exemplarily, the first conductive type guard ring 180 can be formed by an ion implantation process.

[0078] The trench gate 140 includes a gate trench 143 extending from the second surface 102 to the drift region 110, a gate dielectric layer 142 located on the inner surface of the gate trench 143, and a gate 141 located on the side of the gate dielectric layer 142 away from the inner surface of the gate trench 143, wherein the gate 141 is isolated from the inner surface of the gate trench 143 by the gate dielectric layer 142. The trench gate 140 extending from the second surface 102 to the substrate 100 is formed in the active region, including: first, as Figure 1B As shown, the substrate 100 is partially etched from the second surface 102 to form a plurality of gate trenches 143, and a gate dielectric layer 142, such as silicon oxide or other suitable dielectric layer, is formed on the sidewalls and bottom of the gate trenches 143; then, as shown Figure 1C As shown, a gate 141 is deposited in the gate trench 143 to form a trench gate 140 . The gate 141 completely fills the gate trench 143 . The material of the gate 141 may be, for example, polysilicon or other materials suitable for a gate.

[0079] Next, execute step S3, such as Figure 1C As shown, an ion implantation process is performed on the second surface 102 to form a body region 150 of a second conductivity type and an emitter region 160 of a first conductivity type between adjacent trench gates 140, wherein the emitter region 160 is arranged on a side of the body region 150 facing the second surface 102, and a side of the emitter region 160 away from the body region 150 constitutes at least a portion of the second surface 102.

[0080] After forming the body region 150 of the second conductivity type and the emitter region 160 of the first conductivity type, as shown in FIG. Figure 1D and Figure 1E As shown, it also includes the following steps: Figure 1D As shown, an insulating layer 200 and a contact region 170 are formed, wherein the insulating layer 200 is disposed on the second surface 102 and covers the trench gate 140 and a portion of the emitter region 160, the contact region 170 and the emitter region 160 are disposed in parallel on a side of the body region 150 facing the second surface 102, and a side of the contact region 170 away from the body region 150 constitutes a portion of the second surface 102; Figure 1E As shown, emitter metal 300 is formed, which covers insulating layer 200 and a portion of second surface 102, and is in contact with emitter region 160 and contact region 170. Exemplarily, insulating layer 200 also exposes at least a portion of the surface of guard ring 180, and emitter metal 300 is in contact with guard ring 180.

[0081] Next, execute step S4, such as Figure 1FAs shown, an ion implantation process is performed on the first surface 101 to form a field stop region 120 of a first conductivity type and a collector region 130 of a second conductivity type, a drift region 110 is arranged between the field stop region 120 and the body region 150, the trench gate 140 and the guard ring 180, the collector region 130 is arranged on the side of the field stop region 120 facing the first surface 101, and the side of the collector region 130 away from the field stop region 120 constitutes at least a portion of the first surface 101, wherein the field stop region 120 includes a first field stop region 121 located in the active region and a second field stop region 122 located in the terminal region, and the doping concentration of at least a portion of the second field stop region 122 is greater than the doping concentration of the first field stop region 121. By making the doping concentration of at least part of the second field stop region 122 greater than the doping concentration of the first field stop region 121, the free electrons in the second field stop region 122 located in the terminal region can be increased. During the IGBT turn-on process, the collector region 130 of the terminal region will inject holes into the drift region, and the free electrons in the second field stop region 122 can recombine with the holes. By increasing the free electrons in the second field stop region 122, the second field stop region 122 can recombine more holes from the collector region 130 during the IGBT turn-on process, thereby reducing the amount of holes reaching the drift region 110 through the second field stop region 122, that is, the amount of holes injected from the collector region 130 of the terminal region to the drift region 110 during the IGBT turn-on process can be reduced, so that the holes discharged from the drift region 110 during the IGBT turn-off process are reduced, thereby reducing the turn-off loss of the IGBT. Meanwhile, the doping concentration of the first field stop region 121 in the active region of the IGBT structure of the embodiment of the present application does not change, so that other parameters such as the on-state voltage drop of the IGBT are not affected.

[0082] In some examples, such as Figure 1G As shown, the first field stop region 121 has a first doping concentration, and the second field stop region 122 has a second doping concentration, and the second doping concentration is greater than the first doping concentration; or Figure 2 and Figure 3 As shown, the first field stop region 121 has a first doping concentration, and the second field stop region 122 includes a first region 1221 having the first doping concentration and a second region 1222 having the second doping concentration. The second field stop region 122 may include at least one first region 1221 and at least one second region 1222, and the first region 1221 and the second region 1222 are arranged along a direction perpendicular to the first direction (such as Figure 2 ) or along a first direction (as shown Figure 3), wherein the direction perpendicular to the first direction may be the arrangement direction of the plurality of trench gates 140 or the extension direction of the trench gates 140. When the second field stop region 122 includes the first region 1221 and the second region 1222, the second field stop region 122 is formed by multiple ion implantation processes.

[0083] After forming the field stop region 120 and the collector region 130, as shown in FIG. Figure 1G As shown, the step of forming a collector metal 400 is also included. The collector metal 400 is disposed on the first surface 101 and contacts the collector region 130 to form a conductive connection so as to lead out the collector region 130 .

[0084] In the manufacturing method of the IGBT structure of the embodiment of the present application, the doping concentration of at least a part of the second field stop region located in the terminal region is greater than the doping concentration of the first field stop region located in the active region. Therefore, it is possible to reduce the amount of carriers injected into the drift region from 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, reducing the turn-off loss, and at the same time will not affect the on-state voltage drop of the IGBT.

[0085] The present application also provides a semiconductor device in an embodiment, which includes the IGBT structure as described above, wherein the semiconductor device may be a power semiconductor device.

[0086] Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely exemplary and are not intended to limit the scope of the present application to this. Those of ordinary skill in the art may make various changes and modifications therein without departing from the scope and spirit of the present application. All these changes and modifications are intended to be included within the scope of the present application as required by the appended claims.

[0087] In the description provided herein, a large number of specific details are described. However, it is understood that the embodiments of the present application can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0088] Similarly, it should be understood that in order to streamline the present application and help understand one or more of the various inventive aspects, in the description of the exemplary embodiments of the present application, the various features of the present application are sometimes grouped together into a single embodiment, figure, or description thereof. However, the method of the present application should not be interpreted as reflecting the following intention: the claimed application requires more features than the features clearly stated in each claim. More specifically, as reflected in the corresponding claims, the inventive point is that the corresponding technical problem can be solved with features less than all the features of a single disclosed embodiment. Therefore, the claims following the specific embodiment are hereby explicitly incorporated into the specific embodiment, wherein each claim itself serves as a separate embodiment of the present application.

[0089] It will be understood by those skilled in the art that, except for mutually exclusive features, all features disclosed in this specification (including the accompanying claims, abstracts and drawings) and all processes or units of any method or device disclosed in this specification may be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstracts and drawings) may be replaced by an alternative feature that provides the same, equivalent or similar purpose.

[0090] In addition, those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments but not other features, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. For example, in the claims, any one of the claimed embodiments may be used in any combination.

[0091] The above is only a specific implementation method or description of a specific implementation method of the present application, and the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. The protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. An IGBT structure, characterized in that: include: A substrate, comprising an active region and a terminal region located outside the active region, and the substrate has a first surface and a second surface facing away from each other in a first direction; A drift region of a first conductivity type, disposed between the first surface and the second surface; A field stop region of a first conductivity type, disposed on a side of the drift region facing the first surface; A collector region of a second conductivity type is disposed on a side of the field stop region facing the first surface, and a side of the collector region away from the field stop region constitutes at least a portion of the first surface; A plurality of trench gates are spaced apart in the active region and extend from the second surface to the drift region; A body region of the second conductivity type, disposed on a side of the drift region facing the second surface and located between adjacent trench gates; An emitter region of the first conductivity type is disposed on a side of the body region facing the second surface, and a side of the emitter region away from the body region constitutes at least a portion of the second surface; A guard ring of a first conductivity type is disposed in the terminal region and extends from the second surface into the drift region; The field stop region includes a first field stop region located in the active region and a second field stop region located in the terminal region, and the doping concentration of at least a portion of the second field stop region is greater than the doping concentration of the first field stop region.

2. The IGBT structure according to claim 1, characterized in that: The first field stop region has a first doping concentration, and the second field stop region has a second doping concentration, and the second doping concentration is less than the first doping concentration; or The first field stop region has the first doping concentration, and the second field stop region includes a first region having the first doping concentration and a second region having the second doping concentration.

3. The IGBT structure according to claim 2, characterized in that: The second field stop region includes at least one of the first regions and at least one of the second regions, and the first regions and the second regions are arranged along a direction perpendicular to the first direction or along the first direction.

4. The IGBT structure according to claim 2, characterized in that: The second doping concentration is 1.5-2.5 times the first doping concentration.

5. The IGBT structure according to claim 1, characterized in that: Also includes: An insulating layer, disposed on the second surface and covering the trench gate and a portion of the emitter region; An emitter metal covers the insulating layer and a portion of the second surface, and the emitter metal is in contact with the emitter region.

6. The IGBT structure according to claim 5, characterized in that: It also includes a contact region of the second conductivity type, which is arranged in parallel with the emitter region on the side of the body region facing the second surface, and the side of the contact region away from the body region constitutes part of the second surface, and the emitter metal is in contact with the contact region.

7. The IGBT structure according to claim 1, characterized in that: A collector metal is also included, and the collector metal is disposed on the first surface and in contact with the collector region.

8. The IGBT structure according to claim 1, characterized in that: The trench gate comprises a gate trench extending from the second surface to the drift region, a gate dielectric layer located on an inner surface of the gate trench, and a gate located on a side of the gate dielectric layer away from the inner surface of the gate trench.

9. A method for manufacturing an IGBT structure, characterized in that: include: Providing a substrate of a first conductivity type, the substrate comprising an active region and a terminal region located outside the active region, and the substrate having a first surface and a second surface facing away from each other in a first direction; forming a first conductive type guard ring and a plurality of intervally arranged trench gates extending from the second surface into the substrate in the terminal region and the active region respectively; Performing an ion implantation process on the second surface to form a body region of the second conductivity type and an emitter region of the first conductivity type between adjacent trench gates, wherein the emitter region is arranged on a side of the body region facing the second surface, and a side of the emitter region away from the body region constitutes at least a portion of the second surface; An ion implantation process is performed on the first surface to form a field stop region of a first conductivity type and a collector region of a second conductivity type, a drift region is arranged between the field stop region and the body region, the trench gate and the guard ring, the collector region is arranged on a side of the field stop region facing the first surface, and a side of the collector region away from the field stop region constitutes at least a portion of the first surface, wherein the field stop region includes a first field stop region located in the active region and a second field stop region located in the terminal region, and the doping concentration of at least a portion of the second field stop region is greater than the doping concentration of the first field stop region.

10. A semiconductor device, characterized in that: The invention comprises the IGBT structure according to any one of claims 1 to 8.

Images