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 plurality of trench gates, a body region of a second conduction type, an emitter region of the first conduction type, a protection ring of the second conduction type, a collector region of the second conduction type, and a plurality of doped regions of the first conduction type. The substrate comprises an IGBT region and a terminal region located on the outer side of the IGBT region and is provided with a first surface and a second surface which are deviated from each other in the first direction, the collector region is arranged on the side, facing the first surface, of the drift region, and the side, away from the drift region, of the collector region forms at least part of the first surface. The plurality of doped regions are arranged in the collector region of the terminal region at intervals along the direction vertical to the first direction. 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 IGBT region and a terminal region located outside the IGBT region. A guard ring is formed in the terminal region to ensure voltage resistance. During the IGBT turn-on process, taking the collector region as a P-type conductive type as an example, a large number of holes will accumulate in the terminal region, resulting in an increase in the number of holes that need to be discharged from the terminal region 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 problem, according to a first aspect of the present application, an IGBT structure is provided, comprising:

[0007] A substrate, comprising an IGBT region and a terminal region located outside the IGBT region, wherein the substrate has a first surface and a second surface which are opposite to 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 plurality of trench gates are arranged at intervals in the IGBT region and extend from the second surface to the drift region;

[0010] 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;

[0011] 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;

[0012] A guard ring of a second conductivity type 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 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 a portion of the first surface;

[0014] A plurality of first conductivity type doping regions are arranged in the collector region of the terminal region at intervals 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 the present application, multiple first conductive type doping regions are arranged in the second conductive type collector region of the terminal region at intervals along a direction perpendicular to the first direction, which 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, reducing the turn-off loss, and at the same time will not affect the on-state voltage drop of the IGBT.

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

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

[0018] The spacing distance between adjacent doping regions gradually decreases.

[0019] The above technical solution has the following advantages and beneficial effects: through such a setting method, the amount of carriers injected from the collector region of the terminal area to the drift region can be reduced during the IGBT opening 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 shutdown process, further reducing the shutdown loss, and at the same time will not affect the on-state voltage drop of the IGBT.

[0020] Optionally, the multiple doped regions include a doped region adjacent to the IGBT region and a doped region 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 doped region spaced apart from the IGBT region constitutes at least part of the first surface on a side away from the drift region, and the doped region spaced apart from the IGBT region has a thickness in the first direction that is less than the thickness in the first direction of the doped region adjacent to the IGBT region.

[0021] The above technical solution has the following advantages and beneficial effects: through such a setting method, the amount of carriers injected from the collector region of the terminal area to the drift region can be reduced during the IGBT opening 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 shutdown process, further reducing the shutdown loss, and at the same time will not affect the on-state voltage drop of the IGBT, and can also relatively reduce the amount of dopant used when the doping region is formed, thereby reducing the manufacturing cost of the device.

[0022] Optionally, the multiple doping regions include a doping region adjacent to the IGBT region and a doping region spaced apart from the IGBT region, wherein the doping region adjacent to the IGBT region penetrates the collector region of the terminal region in the first direction, and there is a gap between two surfaces of the doping 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: through such a setting method, the amount of carriers injected from the collector region of the terminal area to the drift region can be reduced during the IGBT opening 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 shutdown process, further reducing the shutdown loss, and at the same time will not affect the on-state voltage drop of the IGBT, and can also relatively reduce the amount of dopant used when the doping region is formed, thereby reducing the manufacturing cost of the device.

[0024] Optionally, the plurality of doped regions penetrate 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 compound more holes, reduce the amount of holes discharged during the shutdown process, and further reduce the shutdown loss.

[0026] Optionally, it also includes:

[0027] An insulating layer, disposed on the second surface and covering the trench gate and a portion of the emitter region;

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

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

[0030] A contact region of the second conductivity type is arranged in parallel with the emitter region on a side of the body region facing the second surface, a side of the contact region away from the body region constitutes a part of the second surface, and the emitter metal contacts the contact region.

[0031] 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; the emitter metal and the collector metal respectively lead out the emitter region and the collector region, thereby facilitating their connection with the external circuit; the contact area can improve the current output capacity.

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

[0035] The IGBT structure further includes an injection region of a first conductivity type, which is arranged in the FRD region and parallel to the collector region on a side of the drift region facing the first surface, and a 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, and the IGBT integrating the IGBT region and the FRD region is an RC-IGBT, which has higher integration, smaller junction temperature fluctuation and lower thermal resistance.

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

[0038] Providing a substrate of a first conductivity type, the substrate comprising an IGBT region and a terminal region located outside the IGBT region, and the substrate having a first surface and a second surface facing away from each other in a first direction;

[0039] forming a second 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 IGBT region respectively;

[0040] 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;

[0041] An ion implantation process is performed on the first surface to sequentially form a collector region of the second conductivity type and a plurality of doped regions of the first conductivity type, wherein a drift region is arranged 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 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 a portion of the first surface, and a plurality of doped regions are arranged in the collector region of the terminal region at intervals 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 the present application, multiple first conductive type doping regions are arranged in the second conductive type collector region of the terminal region at intervals along a direction perpendicular to the first direction, which 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, reducing the turn-off loss, and at the same time will not affect the on-state voltage drop of the IGBT.

[0043] The semiconductor device according to the embodiment of the present application includes the above-mentioned IGBT structure.

[0044] 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

[0045] 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.

[0046] 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.

[0047] Figure 2 A cross-sectional view of an IGBT structure in another embodiment of the present application is shown.

[0048] Figure 3 A cross-sectional view of an IGBT structure in another embodiment of the present application is shown.

[0049] Figure 4 A cross-sectional view of an IGBT structure in another embodiment of the present application is shown.

[0050] Figure 5 A cross-sectional view of an IGBT structure in another embodiment of the present application is shown.

[0051] Figure 6 A cross-sectional view of an IGBT structure in another embodiment of the present application is shown.

[0052] Figure 7 A flow chart showing a method for manufacturing an IGBT structure in an embodiment of the present application is shown.

[0053] Reference numerals:

[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 stop region; 170, collector region; 180, injection region; 190, doping region; 200, insulating layer; 300, emitter metal; 400, collector metal. DETAILED DESCRIPTION

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] In the IGBT structure in the related art, taking the collector region as a P-type conductive type as an example, during the turn-on process, current flows from the emitter region to the collector region in the IGBT 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.

[0062] like Figure 1G to Figure 6 As shown, in order to solve the above-mentioned problems, an embodiment of the present 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. In the following, the first conductivity type is set to N type and the second conductivity type is set to P type for description.

[0064] The substrate 100 includes an IGBT region and a terminal region outside the IGBT region, that is, the terminal region surrounds the IGBT region, wherein the IGBT region is the main region responsible for current conduction in the IGBT, and the channel is formed in the IGBT region; the terminal region mainly plays a role in protecting and improving the voltage resistance performance of the IGBT.

[0065] The substrate 100 has a first direction ( Figures 1A to 6 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.

[0066] 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).

[0067] 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.

[0068] A plurality of trench gates 120 are arranged at intervals in the IGBT region and extend from the second surface 102 to the drift region 110. The trench gate 120 includes a gate trench 123 extending from the second surface 102 to 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, and 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 may be a silicon dioxide layer, and the gate 121 may be polysilicon. The side of the trench gate 120 away from the first surface 101 constitutes part of the second surface 102. The arrangement of the trench gate 120 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 120 in the IGBT region 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 120, a conductive channel can be formed around the trench gate 120, so that electrons and holes can move in the channel, thereby controlling the on and off of the IGBT.

[0069] The second conductive type guard ring 130 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. By way of example, a plurality of guard rings 130 disposed at intervals may be formed.

[0070] The body region 140 of the second conductivity type (also referred to as the base region) is disposed on a side of the drift region 110 facing the second surface 102 and is 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 in the IGBT region.

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

[0073] A plurality of first conductivity type doping regions 190 are arranged in the collector region 170 of the terminal region at intervals along a direction perpendicular to the first direction. The doping regions 190 can provide free electrons. During the IGBT turn-on process, the collector region 170 of the terminal region will inject holes into the drift region 110 of the terminal region. The free electrons in the doping regions 190 can recombine with the holes, thereby reducing the amount of holes injected from the collector region 170 of the terminal region to the drift region 110 of the terminal region, so that the number of holes discharged from the drift region 110 during the IGBT turn-off process is reduced, thereby reducing the turn-off loss of the IGBT. The direction perpendicular to the first direction can be the arrangement direction of the plurality of trench gates 120 or the extension direction of the trench gates 120. At the same time, the doping region 190 is arranged in the collector region 170 of the terminal region, and the doping region 190 is not arranged in the collector region 170 of the IGBT region, so that other parameters such as the on-state voltage drop of the IGBT are not affected.

[0074] In some examples, the termination region has a first side proximate to the IGBT region and a second side opposite to the first side (from Figure 1G to Figure 6 In the figure, 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). Wherein, from the second side of the terminal area to the first side of the terminal area, such as Figure 2 As shown, the widths of the plurality of doped regions 190 in a direction perpendicular to the first direction gradually increase; and / or, as shown Figure 3 As shown, the thickness of the plurality of doped regions 190 in the first direction gradually increases; and / or, as shown Figure 4 As shown, the spacing distance between adjacent doping regions 190 gradually decreases. Through the above-mentioned setting, the free electrons that can be provided by the doping region 190 gradually increase from the second side of the terminal region to the first side of the terminal region, that is, in the collector region 170 of the terminal region, the free electrons near the IGBT region are more than the free electrons far from the IGBT region, so that the free electrons in the doping region 190 near the IGBT region can recombine the holes in the collector region 170 of the terminal region while recombine the holes flowing from the collector region 170 of the IGBT region into the terminal region, and can reduce the amount of holes injected from the collector region 170 of the terminal region to the drift region 110 during the IGBT opening process, and reduce the amount of holes flowing from the collector region 170 of the IGBT region to the drift region 110 of the terminal region, thereby reducing the amount of holes discharged during the shutdown process, and further reducing the shutdown loss.

[0075] In some embodiments, Figure 2 As shown, the plurality of doped regions 190 penetrate the collector region 170 of the terminal region in the first direction, so as to enable it to recombine more holes, reduce the amount of holes discharged during the shutdown process, and further reduce the shutdown loss.

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

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

[0078] Through the above-mentioned two settings, the amount of free electrons in the doping region 190 adjacent to the IGBT region can be increased, so that the free electrons in the doping region 190 adjacent to the IGBT region can recombine the holes in the collector region 170 of the terminal region while recombine the holes flowing into the terminal region from the collector region 170 of the IGBT region. During the IGBT opening process, the amount of holes injected from the collector region 170 of the terminal region to the drift region 110 can be reduced while the amount of holes flowing from the collector region 170 of the IGBT region to the drift region 110 of the terminal region can be reduced, thereby reducing the amount of holes discharged during the shutdown process, further reducing the shutdown loss, and relatively reducing the amount of dopant used when the doping region is formed, thereby reducing the manufacturing cost of the device.

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

[0080] The insulating layer 200 is arranged on the second surface 102 and covers the trench gate 120 and part of the emitter region 150. The emitter metal 300 covers the insulating layer 200 and part of the second surface 102, and the emitter metal 300 contacts the emitter region 150 to form a conductive connection, so as to lead out the emitter region 150. The collector metal 400 is arranged on the first surface 101 and contacts the collector region 170 to form a conductive connection, so as to lead out the collector region 170. A contact hole is provided in the portion of the insulating layer 200 corresponding to the emitter region 150, and a part of the emitter region 150 is exposed at the bottom of the contact hole, and the emitter metal 300 contacts the emitter region 150 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 120 can be electrically isolated. Exemplarily, the insulating layer 200 further exposes at least a portion of the surface of the guard ring 130 , and the emitter metal 300 is in contact with the guard ring 130 .

[0081] The contact region 141 and the emitter region 150 are arranged in parallel on the side of the body region 140 facing the second surface 102, and the side of the contact region 141 away from the body region 140 constitutes a part of the second surface 102, and the emitter metal 300 is in contact with the contact region 141. The doping concentration of the contact region 141 is higher than the doping concentration of the body region 140. By simultaneously providing the emitter region 150 of the first conductivity type and the contact region 141 of the second conductivity type, the current output capacity of the IGBT device is effectively improved. Exemplarily, the contact region 141 is located in the IGBT region.

[0082] like Figure 1G to Figure 6 As shown, further, the IGBT structure also includes a field stop (FieldStop) region 160 of the first conductivity type, and the field stop region 160 is arranged between the drift region 110 and the collector region 170, and the doping concentration of the field stop region 160 is higher than the doping concentration of the drift region 110. The main function of the field stop region 160 is to terminate the electric field when the IGBT is turned off, to prevent the electric field from penetrating into the collector region 170, thereby improving the withstand voltage capability of the device. When a high voltage is applied, the field stop region 160 can withstand a part of the electric field, so that the electric field gradually weakens before reaching the collector region 170, avoiding the breakdown of 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. The reduction of the tail current helps to reduce the turn-off loss.

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

[0084] Please continue to refer to Figure 1G to Figure 6, the substrate 100 also includes an FRD (Fast Recovery Diode) 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, wherein the FRD region is a region in the IGBT that plays a role in the freewheeling reverse current, and the IGBT integrated with the IGBT region and the FRD region is an RC-IGBT (Reverse Conducting IGBT). Compared with the IGBT without an integrated FRD region, the RC-IGBT has a higher degree of integration, smaller junction temperature fluctuation, and lower thermal resistance. Exemplarily, a drift region 110, a trench gate 120, and a body region 140 are provided in the FRD region, and the body region 140 in the FRD region serves 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 Figure 1G to Figure 6 As shown, the IGBT structure further includes an implantation region 180 of the first conductivity type, the implantation region 180 is arranged in the FRD region and is arranged in parallel with the collector region 170 on the side of the drift region 110 facing the first surface, and the side of the implantation region 180 away from the drift region 110 constitutes at least part of the first surface 101. Exemplarily, the implantation region 180 acts as a cathode of the diode. Exemplarily, the doping region 190 and the implantation region 180 have the same doping concentration. Exemplarily, the collector metal 400 is also in contact with the implantation region 180. Exemplarily, a field stop region 160 is also arranged between the implantation region 180 and the drift region 110.

[0086] In the IGBT structure of the embodiment of the present application, a plurality of first conductivity type doped regions are arranged in a second conductivity type collector region of a terminal region at intervals 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 the turn-off loss, without affecting the on-state voltage drop of the IGBT.

[0087] 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 , Figure 4 , Figure 5 , Figure 6 as well as Figure 7 A method for manufacturing an IGBT structure according to an embodiment of the present application is exemplified.

[0088] First, execute step S1, such as Figure 1AAs shown, a substrate 100 of a first conductive 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 direction ( Figures 1A to 6 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.

[0089] like Figure 1A As shown, the substrate 100 further 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, and the IGBT integrating the IGBT region and the FRD region is an RC-IGBT.

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

[0091] The trench gate 120 includes a gate trench 123 extending from the second surface 102 to 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, wherein 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 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 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 shown Figure 1C As shown, a gate 121 is deposited in the gate trench 123 to form a trench gate 120 . The gate 121 completely fills the gate trench 123 . The material of the gate 121 may be, for example, polysilicon or other materials suitable for a gate.

[0092] Next, step S3 is performed to perform an ion implantation process on the second surface 102 to form a body region 140 of the second conductivity type and an emitter region 150 of the first conductivity type between adjacent trench gates 120, wherein the emitter region 150 is arranged on a side of the body region 140 facing the second surface 102, and a 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 in 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 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 141 located in the IGBT region are formed, wherein the insulating layer 200 is disposed on the second surface 102 and covers the trench gate 120 and a portion of the emitter region 150, the contact region 141 and the emitter region 150 are disposed in parallel on a side of the body region 140 facing the second surface 102, and a side of the contact region 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, and the emitter metal 300 covers the insulating layer 200 and a portion of the second surface 102, and the emitter metal 300 is in contact with 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 is in contact with the guard ring 130. Exemplarily, the emitter metal 300 is also in contact with the body region 140 in the FRD region.

[0094] Next, step S4 is performed 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, wherein a drift region 110 is disposed 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 130, the collector region 170 is disposed on a side of the drift region 110 facing the first surface 101, and a side of the collector region 170 away from the drift region 110 constitutes at least a portion of the first surface 101, and a plurality of doped regions 190 are disposed in the collector region 170 of the terminal region at intervals along a direction perpendicular to the first direction. Specifically, as Figure 1F As shown, a collector region 170 of the second conductivity type is first formed, and the process may also include a step of forming a field stop region 160 of the first conductivity type by an ion implantation process, wherein the field stop region 160 is located between the collector region 170 and the drift region 110; then, as shown Figure 1G As shown, a plurality of first conductive type doped regions 190 are formed in the collector region 170 of the terminal region. The process may also include the step of forming a first conductive type implantation region 180 in the FRD region by an ion implantation process. The implantation region 180 is arranged in the FRD region and is arranged in parallel with the collector region 170 on the side of the drift region 110 facing the first surface, and the side of the implantation region 180 away from the drift region 110 constitutes at least a portion of the first surface 101.

[0095] A plurality of first conductivity type doping regions 190 are arranged in the collector region 170 of the terminal region at intervals along a direction perpendicular to the first direction. The doping regions 190 can provide free electrons. During the IGBT turn-on process, the collector region 170 of the terminal region will inject holes into the drift region 110 of the terminal region. The free electrons in the doping regions 190 can recombine with the holes, thereby reducing the amount of holes injected from the collector region 170 of the terminal region to the drift region 110 of the terminal region, so that the number of holes discharged from the drift region 110 during the IGBT turn-off process is reduced, thereby reducing the turn-off loss of the IGBT. The direction perpendicular to the first direction can be the arrangement direction of the plurality of trench gates 120 or the extension direction of the trench gates 120. At the same time, the doping region 190 is arranged in the collector region 170 of the terminal region, and the doping region 190 is not arranged in the collector region 170 of the IGBT region, so that other parameters such as the on-state voltage drop of the IGBT are not affected.

[0096] After forming the doped region 190, as 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 170 to form a conductive connection to lead out the collector region 170. Exemplarily, the collector metal 400 also contacts the implantation region 180.

[0097] In the manufacturing method of the IGBT structure of the embodiment of the present application, a plurality of first conductive type doping regions are arranged in a second conductive type collector region of the terminal region at intervals 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 the turn-off loss, while not affecting the on-state voltage drop of the IGBT.

[0098] 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.

[0099] 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.

[0100] 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.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] 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 IGBT region and a terminal region located outside the IGBT region, wherein the substrate has a first surface and a second surface which are opposite to each other in a first direction; A drift region of a first conductivity type, disposed between the first surface and the second surface; A plurality of trench gates are arranged at intervals in the IGBT 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 second conductivity type 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 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 a portion of the first surface; A plurality of first conductivity type doping regions are arranged in the collector region of the terminal region at intervals along a direction perpendicular to the first direction.

2. The IGBT structure according to claim 1, characterized in that: The terminal region has a first side close to the IGBT region and a second side opposite to the first side, and widths of the plurality of doped regions in a direction perpendicular to the first direction gradually increase from the second side to the first side; and / or The thicknesses of the plurality of doped regions in the first direction gradually increase; and / or The spacing distance between adjacent doping regions gradually decreases.

3. The IGBT structure according to claim 1 or 2, characterized in that: The multiple doped regions include a doped region adjacent to the IGBT region and a doped region 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 doped region spaced apart from the IGBT region constitutes at least part of the first surface on a side away from the drift region, and the doped region spaced apart from the IGBT region has a thickness in the first direction that is less than the thickness in the first direction of the doped region adjacent to the IGBT region.

4. The IGBT structure according to claim 1 or 2, characterized in that: The multiple doped regions include a doped region adjacent to the IGBT region and a doped region 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.

5. 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.

6. The IGBT structure according to any one of claims 1 to 5, 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 covering the insulating layer and a portion of the second surface, the emitter metal being in contact with the emitter region; A collector metal, disposed on the first surface and in contact with the collector region; A contact region of the second conductivity type is arranged in parallel with the emitter region on a side of the body region facing the second surface, a side of the contact region away from the body region constitutes a part of the second surface, and the emitter metal contacts the contact region.

7. The IGBT structure according to any one of claims 1 to 6, 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.

8. The IGBT structure according to any one of claims 1 to 7, characterized in that: The substrate further includes an FRD region disposed adjacent to the IGBT region, the terminal region is located outside the FRD region, and the drift region, the body region and the trench gate are disposed in the FRD region; The IGBT structure further includes an injection region of a first conductivity type, which is arranged in the FRD region and parallel to the collector region on a side of the drift region facing the first surface, and a side of the injection region away from the drift region constitutes at least a portion of the first surface.

9. A method for manufacturing an IGBT structure, characterized in that: include: Providing a substrate of a first conductivity type, the substrate comprising an IGBT region and a terminal region located outside the IGBT region, and the substrate having a first surface and a second surface facing away from each other in a first direction; Forming a second 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 IGBT 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 sequentially form a collector region of the second conductivity type and a plurality of doped regions of the first conductivity type, wherein a drift region is arranged 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 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 a portion of the first surface, and a plurality of doped regions are arranged in the collector region of the terminal region at intervals along a direction perpendicular to the first direction.

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

Images