Superjunction vertical double diffused metal oxide semiconductor device and preparation method thereof

Abstract

The present application relates to a superjunction vertical double diffused metal oxide semiconductor device and a preparation method thereof, wherein the superjunction vertical double diffused metal oxide semiconductor device comprises: a substrate structure; a superjunction structure, arranged in the substrate structure; the superjunction structure comprises a first doping region and a second doping region arranged alternately in sequence along a first direction; the first direction is perpendicular to the thickness direction of the substrate structure; a first floating doping region, arranged in the first doping region; a body region, arranged in the substrate structure; the body region is located on the side of the first doping region close to the front of the substrate structure and is connected to the first doping region; along the thickness direction of the substrate structure, there is a first spacing between the body region and the first floating doping region; a source region, arranged in the body region; a gate, arranged on the substrate structure; wherein the substrate structure, the second doping region, the first floating doping region and the source region are of the first conductivity type, and the first doping region and the body region are of the second conductivity type. The present application can improve the problem of poor dynamic characteristics.

Description

Technical Field

[0001] The present application relates to the field of integrated circuit technology, and in particular to a superjunction vertical double diffused metal oxide semiconductor device and a preparation method thereof. Background Art

[0002] Due to its special functions, the power metal-oxide-semiconductor long-effect transistor structure has a wide range of applications in a very broad field, such as disk drives, automotive electronics, and power devices. Taking power devices as an example, VDMOS (Vertical double-diffused metal oxide semiconductor) is used in ultra-large-scale integrated circuit devices for power devices. It has the advantages of low switching loss, high input impedance, low driving power, and good frequency characteristics, and is widely used.

[0003] In VDMOS devices, increasing the breakdown voltage of the device and reducing the on-resistance of the device are a contradiction. Superjunction VDMOS devices use a new voltage-resistant layer structure, using a series of alternating P-type and N-type semiconductor thin layers to deplete the P-type and N-type regions at a lower reverse voltage, achieving mutual charge compensation, so that the N-type region can achieve a high breakdown voltage at a high doping concentration, thereby simultaneously obtaining low on-resistance and high breakdown voltage, breaking the theoretical limit of on-resistance of traditional VDMOS devices. Traditional VDMOS devices use deep trench technology to make superjunction structures.

[0004] However, traditional superjunction VDMOS devices have problems such as poor dynamic characteristics and high manufacturing difficulty. Summary of the invention

[0005] Based on this, it is necessary to provide a super junction vertical double diffused metal oxide semiconductor device and a method for preparing the same in order to address at least one of the above problems.

[0006] In order to achieve the above objectives, in a first aspect, the present application provides a super junction vertical double diffused metal oxide semiconductor device, comprising:

[0007] Substrate structure;

[0008] A super junction structure is provided in the substrate structure; the super junction structure comprises first doping regions and second doping regions which are alternately arranged in sequence along a first direction; the first direction is perpendicular to a thickness direction of the substrate structure;

[0009] A first floating doping region, disposed in the first doping region;

[0010] A body region is provided in the substrate structure; the body region is located on a side of the first doped region close to the front side of the substrate structure and is connected to the first doped region; along the thickness direction of the substrate structure, a first distance exists between the body region and the first floating doped region;

[0011] a source region, disposed in the body region;

[0012] A gate, disposed on the substrate structure;

[0013] The substrate structure, the second doped region, the first floating doped region and the source region are of a first conductivity type, and the first doped region and the body region are of a second conductivity type.

[0014] In one of the embodiments, a second distance exists between a side surface of the first floating doped region close to the back side of the substrate structure and a side surface of the first doped region close to the back side of the substrate structure.

[0015] In one embodiment, the ratio of the first spacing to the dimension of the first floating doping region along the thickness direction of the substrate structure is between 5 and 8;

[0016] And / or, the ratio of the second spacing to the dimension of the first floating doping region along the thickness direction of the substrate structure is between 1-2.

[0017] In one embodiment, the super junction vertical double diffused metal oxide semiconductor device further includes a second floating doping region, the second floating doping region is arranged in the first doping region, and is located on a side of the first floating doping region close to the front side of the substrate structure; the second floating doping region and the first floating doping region are arranged at intervals;

[0018] The second floating doping region is of a second conductivity type, and a doping concentration of the second floating doping region is greater than a doping concentration of the first doping region.

[0019] In one embodiment, the first doping region includes a first sub-doping region and a second sub-doping region, and the second sub-doping region is located on a side of the first sub-doping region close to the front side of the substrate structure;

[0020] The first floating doping region is located in the first sub-doping region, and the second floating doping region is located in the second sub-doping region.

[0021] In one of the embodiments, the first sub-doping region and the second sub-doping region are connected;

[0022] A size of a surface of the second sub-doping region close to the back side of the substrate structure along the first direction is smaller than a size of a surface of the first sub-doping region close to the front side of the substrate structure along the first direction.

[0023] In one of the embodiments, along the direction from the back side of the substrate structure to the front side of the substrate structure, the size of the first sub-doped region along the first direction gradually increases;

[0024] And / or, along the direction from the back side of the substrate structure to the front side of the substrate structure, the size of the second sub-doping region along the first direction gradually increases.

[0025] In one embodiment, the first doping region further includes a third sub-doping region, and the third sub-doping region is located between the first sub-doping region and the second sub-doping region;

[0026] The dimension of a side surface of the third sub-doping region close to the back side of the substrate structure along the first direction is smaller than the dimension of a side surface of the first sub-doping region close to the front side of the substrate structure along the first direction; the dimension of a side surface of the second sub-doping region close to the back side of the substrate structure along the first direction is smaller than the dimension of a side surface of the third sub-doping region close to the front side of the substrate structure along the first direction.

[0027] In one of the embodiments, along the direction from the back side of the substrate structure to the front side of the substrate structure, the size of the third sub-doping region along the first direction gradually increases.

[0028] In a second aspect, the present application provides a method for preparing a superjunction vertical double diffused metal oxide semiconductor device, comprising:

[0029] A substrate structure, a super junction structure and a first floating doped region are formed; the super junction structure is arranged in the substrate structure, the super junction structure includes a first doped region and a second doped region arranged alternately in sequence along a first direction, and the first floating doped region is arranged in the first doped region; the first direction is perpendicular to the thickness direction of the substrate structure;

[0030] A body region, a source region and a gate are formed; the body region is arranged in the substrate structure and is located on the side of the first doping region close to the front side of the substrate structure, and the body region is connected to the first doping region; along the thickness direction of the substrate structure, there is a first spacing between the body region and the first floating doping region; the source region is arranged in the body region; the gate is arranged on the substrate structure; wherein the substrate structure, the second doping region, the first floating doping region and the source region are of the first conductivity type, and the first doping region and the body region are of the second conductivity type.

[0031] The superjunction vertical double diffused metal oxide semiconductor device and the preparation method thereof provided in the embodiment of the present application are provided with a first floating doping region in the first doping region of the superjunction structure, the doping type of the first floating doping region is opposite to the doping type of the first doping region, and there is a first spacing between the body region and the first floating doping region. In this way, the resistance of the first doping region in the reverse extraction process can be increased, and the extraction speed of non-equilibrium holes in the reverse recovery process can be reduced, thereby improving the dynamic characteristics of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments or exemplary embodiments of the present application, the drawings required for use in the description of the embodiments or exemplary embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 It is a schematic diagram of the cross-sectional structure of a superjunction vertical double diffused metal oxide semiconductor device provided in one embodiment of the present application.

[0034] Figure 2 It is a schematic diagram of the cross-sectional structure of another superjunction vertical double diffused metal oxide semiconductor device provided in one embodiment of the present application.

[0035] Figure 3 A comparison curve diagram of reverse recovery characteristics of different devices provided in one embodiment of the present application.

[0036] Figure 4 A schematic flow chart of a method for preparing a superjunction vertical double diffused metal oxide semiconductor device provided in one embodiment of the present application.

[0037] Figure 5-Figure 10 for Figure 4 Schematic diagram of the cross-sectional structure of the device during the preparation method shown.

[0038] Description of reference numerals:

[0039] 1. Super junction vertical double diffused metal oxide semiconductor device; 11. Substrate structure; 111. Base; 112. Epitaxial layer; 112a. First epitaxial sublayer; 112b. Second epitaxial sublayer; 113. Groove; 12. Super junction structure; 121. First doped region; 121a. First sub-doped region; 121b. Second sub-doped region; 121c. Third sub-doped region; 122. Second doped region; 13. First floating doped region; 14. Body region; 15. Source region; 16. Gate; 17. Second floating doped region. DETAILED DESCRIPTION

[0040] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0042] It should be understood that when an element or layer is referred to as being "on, adjacent to, connected to or coupled to other elements or layers, it may be directly on, adjacent to, connected to or coupled to other elements or layers, or there may be intervening elements or layers. On the contrary, when an element is referred to as being "directly on, directly adjacent to, directly connected to or directly coupled to other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers, doping types and / or parts, these elements, components, regions, layers, doping types and / or parts should not be limited by these terms. These terms are merely used to distinguish one element, component, region, layer, doping type or part from another element, component, region, layer, doping type or part. Therefore, without departing from the teachings of the present application, the first element, component, region, layer, doping type or portion discussed below may be represented as a second element, component, region, layer or portion; for example, the first doping type may be referred to as the second doping type, and similarly, the second doping type may be referred to as the first doping type; the first doping type and the second doping type are different doping types, for example, the first doping type may be P-type and the second doping type may be N-type, or the first doping type may be N-type and the second doping type may be P-type.

[0043] Spatially relative terms such as "under," "beneath," "below," "under," "above," "above," and the like may be used herein to describe the relationship of an element or feature shown in the figures to other elements or features. It should be understood that, in addition to the orientations shown in the figures, spatially relative terms also include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is flipped, an element or feature described as "under other elements" or "under it" or "under it" will be oriented as being "above" the other elements or features. Thus, the exemplary terms "under" and "under" may include both upper and lower orientations. In addition, the device may also include additional orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptors used herein are interpreted accordingly.

[0044] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, in this specification, the term "and / or" includes any and all combinations of the relevant listed items.

[0045] Embodiments of the application are described herein with reference to cross-sectional views that are schematic diagrams of ideal embodiments (and intermediate structures) of the application, so that 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 of the zones shown herein, but rather include shape deviations due to, for example, manufacturing techniques. For example, an implanted region shown as a rectangle typically has rounded or curved features and / or an implant concentration gradient at its edges, rather than a binary change from an implanted region to a non-implanted region. Similarly, a buried region formed by implantation may result in some implantation in the region between the buried region and the surface through which the implantation is performed. Therefore, the regions shown in the figures are schematic in nature, their shapes do not represent the actual shape of the region of the device, and do not limit the scope of the application.

[0046] First, refer to Figure 1As shown, the embodiment of the present application provides a super junction vertical double diffused metal oxide semiconductor device 1, which specifically includes a substrate structure 11, a super junction structure 12, a first floating doped region 13, a body region 14, a source region 15 and a gate 16. The super junction structure 12 is arranged in the substrate structure 11, and the super junction structure 12 includes a first doped region 121 and a second doped region 122 arranged alternately in sequence along a first direction X, and the doping types of the first doped region 121 and the second doped region 122 are opposite. The first direction X is perpendicular to the thickness direction of the substrate structure 11. The first floating doped region 13 is arranged in the first doped region 121. The body region 14 is arranged in the substrate structure 11; the body region 14 is located on the side of the first doped region 121 close to the front side of the substrate structure 11, that is, the body region 14 is located above the first doped region 121. The body region 14 is connected to the first doped region 121. Along the thickness direction of the substrate structure 11, there is a first spacing L1 between the body region 14 and the first floating doping region 13, that is, in the vertical direction, there is a first spacing L1 between the body region 14 and the first floating doping region 13. The source region 15 is disposed in the body region 14. The gate 16 is disposed on the substrate structure 11, that is, the gate 16 is disposed on the front side of the substrate structure 11.

[0047] The substrate structure 11, the second doped region 122, the first floating doped region 13 and the source region 15 are of the first conductivity type, and the first doped region 121 and the body region 14 are of the second conductivity type. It can be understood that one of the first conductivity type and the second conductivity type is N-type and the other is P-type.

[0048] In a specific embodiment, the first conductivity type is N type, and the second conductivity type is P type. Thus, the first doping region 121 is equivalent to a P column, and the second doping region 122 is equivalent to an N column.

[0049] Here, it should be noted that the super junction structure 12 may include a first doping region 121 and a second doping region 122, or may include multiple first doping regions 121 and multiple second doping regions 122. When the number of the first doping regions 121 and the second doping regions 122 are both multiple, the first doping regions 121 and the second doping regions 122 are arranged alternately in sequence along the first direction X.

[0050] The superjunction vertical double diffused metal oxide semiconductor device 1 provided in the embodiment of the present application is provided with a first floating doping region 13 in the first doping region 121 of the superjunction structure 12, the doping type of the first floating doping region 13 is opposite to the doping type of the first doping region 121, and a first spacing L1 is provided between the body region 14 and the first floating doping region 13. In this way, it is equivalent to introducing a suspended first conductive type column (first floating doping region 13) in the second conductive type column (first doping region 121), so that the upper part of the first doping region 121 (the region where the first floating doping region 13 is not provided) and the lower part of the first doping region 121 (the region where the first floating doping region 13 is provided) have a resistance difference, thereby increasing the resistance of the first doping region 121 in the reverse extraction process, reducing the extraction speed of non-equilibrium holes in the reverse recovery process, and thus improving the dynamic characteristics of the device.

[0051] In one embodiment, the material of the substrate structure 11 can be single crystal silicon, polycrystalline silicon, amorphous silicon, germanium silicon compound, silicon-on-insulator (SOI) or low temperature polysilicon (LTPS), or other materials known to those skilled in the art.

[0052] In one embodiment, the substrate structure 11 includes a base 111 and an epitaxial layer 112 disposed on the base 111 , and the super junction structure 12 , the first floating doped region 13 , the body region 14 and the source region 15 are all disposed in the epitaxial layer 112 .

[0053] In one embodiment, if Figure 1 As shown, there is a second distance L2 between the side surface of the first floating doping region 13 close to the back side of the substrate structure 11 and the side surface of the first doping region 121 close to the back side of the substrate structure 11, that is, the distance between the bottom surface of the first floating doping region 13 and the bottom surface of the first doping region 121 is the second distance L2. In this way, it is beneficial to increase the resistance of the first doping region 121 during the reverse extraction process, reduce the extraction speed of non-equilibrium holes during the reverse recovery process, and further improve the dynamic characteristics of the device.

[0054] In one embodiment, referring to Figure 1 As shown, the ratio of the first spacing L1 to the dimension of the first floating doping region 13 along the thickness direction of the substrate structure 11 is between 5 and 8, wherein the dimension of the first floating doping region 13 along the thickness direction of the substrate structure 11 is L3. Exemplarily, the ratio of L1 to L3 can be 5, 6, 7, 8 or between any two of the above values.

[0055] In this way, L1 can represent the top embedding depth of the first floating doping region 13, and L3 can represent the height of the first floating doping region 13 itself. The above setting can make the ratio between the top embedding depth and the height of the first floating doping region 13 more appropriate, which is beneficial to increase the resistance of the first doping region 121 during the reverse extraction process.

[0056] In one embodiment, referring to Figure 1 As shown, the ratio of the second spacing L2 to the dimension of the first floating doping region 13 along the thickness direction of the substrate structure 11 is between 1 and 2, wherein the dimension of the first floating doping region 13 along the thickness direction of the substrate structure 11 is L3. Exemplarily, the ratio of L2 to L3 can be 1, 1.5, 2, or between any two of the above values.

[0057] In this way, L2 can represent the bottom embedding depth of the first floating doping region 13, and L3 can represent the height of the first floating doping region 13 itself. The above setting can make the ratio between the bottom embedding depth and the height of the first floating doping region 13 more appropriate, which is beneficial to increase the resistance of the first doping region 121 during the reverse extraction process.

[0058] In one embodiment, if Figure 2 As shown, the superjunction vertical double diffused metal oxide semiconductor device 1 further includes a second floating doping region 17, which is arranged in the first doping region 121 and is located on the side of the first floating doping region 13 close to the front surface of the substrate structure 11; the second floating doping region 17 and the first floating doping region 13 are arranged at intervals. The second floating doping region 17 is of the second conductivity type, and the doping concentration of the second floating doping region 17 is greater than the doping concentration of the first doping region 121.

[0059] In this way, it is equivalent to introducing a second conductive type column (second floating doping region 17) with a higher concentration in the upper part of the second conductive type column (first doping region 121), so that the upper part of the first doping region 121 (the region where the second floating doping region 17 is set) and the lower part of the first doping region 121 (the region where the first floating doping region 13 is set) have a resistance difference, thereby increasing the resistance of the first doping region 121 during the reverse extraction process, reducing the extraction speed of non-equilibrium holes during the reverse recovery process, and thus improving the dynamic characteristics of the device.

[0060] In one embodiment, if Figure 1As shown, the first doping region 121 includes a first sub-doping region 121a and a second sub-doping region 121b, and the second sub-doping region 121b is located on the side of the first sub-doping region 121a close to the front side of the substrate structure 11. The first floating doping region 13 is located in the first sub-doping region 121a and is connected to the second sub-doping region 121b. It should be noted that the first sub-doping region 121a and the second sub-doping region 121b can be manufactured in different manufacturing processes respectively. The above arrangement can facilitate the arrangement of the first floating doping region 13 in the first sub-doping region 121a. For example, first, a groove 113 is etched in the first epitaxial sublayer 112a, and then the second conductive type of doping material is backfilled in the groove 113 to form a first sub-doped region 121a, and then the first conductive type of doping material is backfilled to form a first floating doped region 13, and then the second epitaxial sublayer 112b is formed on the first epitaxial sublayer 112a, and then the groove 113 is etched on the second epitaxial sublayer 112b, and then the second conductive type of doping material is backfilled in the groove 113 to form a second sub-doped region 121b.

[0061] It should be noted that this embodiment is equivalent to using a process of etching the groove 113 multiple times to produce a first doped region 121 with a relatively large depth-to-width ratio. Compared with the related technology of using a single etching process to produce the first doped region 121, this embodiment can reduce the requirements of the etching process on the depth-to-width ratio of the groove 113, thereby reducing the difficulty of the manufacturing process.

[0062] Please refer to Figure 3 As shown, the inventors of the present application have carried out simulations on traditional devices and devices in the embodiments of the present application. It can be seen from the figure that, compared with traditional devices, the devices in the embodiments of the present application can reduce dI / dt by about 10% and △IDS by about 50%, which significantly improves the ringing phenomenon.

[0063] In one embodiment, if Figure 2 As shown, the first doping region 121 includes a first sub-doping region 121a and a second sub-doping region 121b, and the second sub-doping region 121b is located on the side of the first sub-doping region 121a close to the front side of the substrate structure 11. The first floating doping region 13 is located in the first sub-doping region 121a, and the second floating doping region 17 is arranged in the second sub-doping region 121b. It should be noted that the first sub-doping region 121a and the second sub-doping region 121b are respectively manufactured in different manufacturing processes. The above arrangement can facilitate the arrangement of the first floating doping region 13 and the second floating doping region 17 in the first doping region 121. The specific manufacturing process will not be repeated here.

[0064] In one embodiment, if Figure 1As shown, the first sub-doping region 121a is connected to the second sub-doping region 121b. The size of the second sub-doping region 121b on one side close to the back side of the substrate structure 11 along the first direction X is smaller than the size of the first sub-doping region 121a on one side close to the front side of the substrate structure 11 along the first direction X. Figure 1 For example, the width of the bottom surface of the second sub-doping region 121b is smaller than the width of the top surface of the first sub-doping region 121a. This is conducive to making the width of the second doping region 122 more uniform, thereby ensuring the performance of the super junction structure 12.

[0065] In one embodiment, along the direction from the back side of the substrate structure 11 to the front side of the substrate structure 11, the size of the first sub-doped region 121a along the first direction X gradually increases. Figure 1 Taking the direction in FIG. 1 as an example, from top to bottom, the width of the first sub-doping region 121a gradually decreases. Figure 1 Taking the cross section in FIG. 1 as an example, the shape of the first sub-doping region 121 a is an inverted trapezoid.

[0066] In one embodiment, along the direction from the back side of the substrate structure 11 to the front side of the substrate structure 11, the size of the second sub-doping region 121b along the first direction X gradually increases. Figure 1 In the example, the width of the second sub-doping region 121b decreases gradually from top to bottom. Figure 1 Taking the cross section in FIG. 1 as an example, the shape of the second sub-doping region 121 b is an inverted trapezoid.

[0067] In one embodiment, if Figure 2 As shown, the first doping region 121 also includes a third sub-doping region 121c, and the third sub-doping region 121c is located between the first sub-doping region 121a and the second sub-doping region 121b. The size of the side surface of the third sub-doping region 121c close to the back side of the substrate structure 11 along the first direction X is smaller than the size of the side surface of the first sub-doping region 121a close to the front side of the substrate structure 11 along the first direction X; the size of the side surface of the second sub-doping region 121b close to the back side of the substrate structure 11 along the first direction X is smaller than the size of the side surface of the third sub-doping region 121c close to the front side of the substrate structure 11 along the first direction X. Figure 2 For example, the width of the bottom surface of the third sub-doping region 121c is smaller than the width of the top surface of the first sub-doping region 121a, and the width of the bottom surface of the second sub-doping region 121b is smaller than the width of the top surface of the third sub-doping region 121c. In this way, the width of the second doping region 122 is more uniform, thereby ensuring the performance of the super junction structure 12.

[0068] It should be noted that the structure in this embodiment can better increase the resistance of the first doped region 121 during the reverse extraction process, reduce the extraction speed of non-equilibrium holes during the reverse recovery process, and thus better improve the dynamic characteristics of the device.

[0069] In one embodiment, along the direction from the back side of the substrate structure 11 to the front side of the substrate structure 11, the size of the third sub-doping region 121c along the first direction X gradually increases. Figure 2 Taking the direction in FIG. 1 as an example, from top to bottom, the width of the third sub-doping region 121c gradually decreases. Figure 2 Taking the cross section in FIG. 1 as an example, the shape of the third sub-doping region 121 c is an inverted trapezoid.

[0070] Second, as Figure 4 As shown, the present application provides a method for preparing a super junction vertical double diffused metal oxide semiconductor device 1, comprising the following steps:

[0071] S100: forming a substrate structure, a super junction structure and a first floating doping region. The super junction structure 12 is disposed in the substrate structure 11, and the super junction structure 12 includes a first doping region 121 and a second doping region 122 arranged alternately in sequence along a first direction X, and the first floating doping region 13 is disposed in the first doping region 121; the first direction X is perpendicular to the thickness direction of the substrate structure 11.

[0072] S200: forming a body region, a source region and a gate. The body region 14 is disposed in the substrate structure 11 and is located on the side of the first doping region 121 close to the front surface of the substrate structure 11, and the body region 14 is connected to the first doping region 121; along the thickness direction of the substrate structure 11, there is a first spacing L1 between the body region 14 and the first floating doping region 13; the source region 15 is disposed in the body region 14; the gate 16 is disposed on the substrate structure 11; wherein the substrate structure 11, the second doping region 122, the first floating doping region 13 and the source region 15 are of the first conductivity type, and the first doping region 121 and the body region 14 are of the second conductivity type.

[0073] The method for preparing the superjunction vertical double diffused metal oxide semiconductor device 1 provided in the embodiment of the present application is to set a first floating doping region 13 in the first doping region 121 of the superjunction structure 12, wherein the doping type of the first floating doping region 13 is opposite to the doping type of the first doping region 121, and a first spacing L1 is provided between the body region 14 and the first floating doping region 13. In this way, it is equivalent to introducing a suspended first conductive type column (first floating doping region 13) in the second conductive type column (first doping region 121), so that the upper part of the first doping region 121 (the region where the first floating doping region 13 is not provided) and the lower part of the first doping region 121 (the region where the first floating doping region 13 is provided) have a resistance difference, thereby increasing the resistance of the first doping region 121 during the reverse extraction process, reducing the extraction speed of non-equilibrium holes during the reverse recovery process, and thus improving the dynamic characteristics of the device.

[0074] In one embodiment, referring to Figure 5-Figure 10 As shown, S100: forming a substrate structure 11, a super junction structure 12 and a first floating doped region 13, specifically comprising the following steps:

[0075] S110 : forming a first epitaxial sublayer 112 a on the substrate 111 .

[0076] S120 : Etching a trench 113 on the first epitaxial sub-layer 112 a .

[0077] S130 : filling and backfilling the second conductive type doping material in the trench 113 to form a first sub-doping region 121 a , and then backfilling the first conductive type doping material to form a first floating doping region 13 .

[0078] S140 : forming a second epitaxial sublayer 112 b on the first epitaxial sublayer 112 a .

[0079] S150 : Etching a trench 113 on the second epitaxial sub-layer 112 b .

[0080] S160 : backfilling the trench 113 with a doping material of the second conductivity type to form a second doping sub-region 121 b .

[0081] It should be understood that, in the embodiments of the present application, although the various steps in the flowchart of the accompanying drawings are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless there is a clear description in this article, the execution of these steps is not strictly limited in order, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the accompanying drawings may include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of the steps or stages in other steps.

[0082] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", "ideal embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0083] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features of the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0084] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A superjunction vertical double diffused metal oxide semiconductor device, characterized in that: include: Substrate structure; A super junction structure is provided in the substrate structure; the super junction structure comprises first doping regions and second doping regions which are alternately arranged in sequence along a first direction; the first direction is perpendicular to a thickness direction of the substrate structure; A first floating doping region, disposed in the first doping region; A body region is provided in the substrate structure; the body region is located on a side of the first doped region close to the front side of the substrate structure and is connected to the first doped region; along the thickness direction of the substrate structure, a first distance exists between the body region and the first floating doped region; a source region, disposed in the body region; A gate, disposed on the substrate structure; The substrate structure, the second doped region, the first floating doped region and the source region are of a first conductivity type, and the first doped region and the body region are of a second conductivity type; The super junction vertical double diffused metal oxide semiconductor device further includes a second floating doping region, which is arranged in the first doping region and located on a side of the first floating doping region close to the front side of the substrate structure; the second floating doping region and the first floating doping region are arranged at intervals; The second floating doped region is of a second conductivity type, and a doping concentration of the second floating doped region is greater than a doping concentration of the first doped region; The first doping region includes a first sub-doping region and a second sub-doping region, and the second sub-doping region is located on a side of the first sub-doping region close to the front side of the substrate structure; The first floating doping region is located in the first sub-doping region, and the second floating doping region is located in the second sub-doping region; The first doping region further includes a third sub-doping region, and the third sub-doping region is located between the first sub-doping region and the second sub-doping region; a size of a side surface of the third sub-doping region close to the back side of the substrate structure along the first direction is smaller than a size of a side surface of the first sub-doping region close to the front side of the substrate structure along the first direction; a size of a side surface of the second sub-doping region close to the back side of the substrate structure along the first direction is smaller than a size of a side surface of the third sub-doping region close to the front side of the substrate structure along the first direction; One end of the second floating doped region close to the body region is connected to the body region, and one end of the second floating doped region away from the body region is spaced apart from the third sub-doped region; A portion of the third sub-doping region is directly connected to a portion of the first sub-doping region.

2. The superjunction vertical double diffused metal oxide semiconductor device according to claim 1, characterized in that: A second distance exists between a side surface of the first floating doped region close to the back side of the substrate structure and a side surface of the first doped region close to the back side of the substrate structure.

3. The superjunction vertical double diffused metal oxide semiconductor device according to claim 2, characterized in that: The ratio of the first spacing to the dimension of the first floating doping region along the thickness direction of the substrate structure is between 5 and 8; And / or, the ratio of the second spacing to the dimension of the first floating doping region along the thickness direction of the substrate structure is between 1-2.

4. The superjunction vertical double diffused metal oxide semiconductor device according to claim 1, characterized in that: From the back side of the substrate structure to the front side of the substrate structure, the size of the first sub-doped region along the first direction gradually increases; And / or, along the direction from the back side of the substrate structure to the front side of the substrate structure, the size of the second sub-doping region along the first direction gradually increases.

5. The superjunction vertical double diffused metal oxide semiconductor device according to claim 1, characterized in that: Along the direction from the back side of the substrate structure to the front side of the substrate structure, the size of the third sub-doping region along the first direction gradually increases.

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