Tilted super junction structure and method of manufacturing the same, semiconductor device

Abstract

The present disclosure relates to a tilted super junction structure, a manufacturing method thereof, and a semiconductor device. The method comprises: forming a plurality of doped layers, the plurality of doped layers are sequentially stacked along a first direction, each of the plurality of doped layers has a first doping type, and doping concentrations of the plurality of doped layers sequentially increase; forming a super junction trench extending into the plurality of doped layers and obtaining a first pillar region based on the plurality of doped layers, wherein a sidewall of the super junction trench is tilted relative to the first direction, and the first pillar region comprises a plurality of first doped portions sequentially stacked along the first direction; and forming a second pillar region filling the super junction trench, the second pillar region has a second doping type. The method can realize a tilted super junction structure with guaranteed performance.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of semiconductor technology, and in particular, to a tilted super junction structure, a manufacturing method thereof, and a semiconductor device. BACKGROUND

[0002] Semiconductor power devices are important components of power electronic devices, and the industry has high expectations for the control loss and efficiency improvement of power electronic devices. Super junction devices can break through the one-dimensional theoretical performance limit of ordinary devices and have great performance advantages and application potential in the medium and high voltage fields.

[0003] Super junction devices prepared based on a trench etching and epitaxial backfill process route have the advantage of low cost, but it is relatively difficult to form super junction trenches with high verticality by dry etching.

[0004] Generally, the industry expects to improve the verticality of super junction trenches to ensure local charge imbalance in the vertical direction of the super junction, but the effect is not satisfactory. When the local charge imbalance problem of the super junction device is serious, the lateral depletion process becomes longer, causing the central electric field peak to rise, thereby reducing the blocking performance of the super junction device. SUMMARY

[0005] Therefore, it is necessary to provide a tilted super junction structure and a method for manufacturing the tilted super junction structure in view of the local charge imbalance problem of the super junction device.

[0006] The method for manufacturing the tilted super junction structure provided by the embodiments of the present disclosure includes: forming a plurality of doped layers, the plurality of doped layers are sequentially stacked along a first direction, the plurality of doped layers all have a first doping type, and the doping concentrations of the plurality of doped layers sequentially increase; forming a super junction trench extending into the plurality of doped layers and obtaining a first pillar region based on the plurality of doped layers, wherein the sidewall of the super junction trench is inclined relative to the first direction, and the first pillar region includes a plurality of first doped parts sequentially stacked along the first direction; and forming a second pillar region filling the super junction trench, the second pillar region having a second doping type.

[0007] The method for manufacturing the tilted super junction structure provided by the embodiments of the present disclosure has the advantages of low cost and easy implementation, and based on the traditional etching and epitaxial backfill process, the sidewall inclination of the super junction trench does not have to be controlled too much, and a tilted super junction structure with guaranteed performance is achieved through a gradually changing doping distribution mode.

[0008] In some embodiments, in the step of forming the doped layer, the in-situ doping concentration of the doped layer is controlled according to the sidewall inclination of the super junction trench to be formed.

[0009] In this method, in-situ doping can be achieved through epitaxial processes, and the doping concentration can be controlled more precisely. Furthermore, by controlling the in-situ doping concentration of the doped layer, it is possible to effectively fabricate high-performance tilted superjunction structures based on the slant of the actual etching process.

[0010] In some embodiments, the step of forming the second pillar region includes: forming a plurality of second doped portions stacked sequentially along a first direction, wherein the doping concentration of the plurality of second doped portions decreases sequentially.

[0011] By setting the second pillar region to be gradually doped, the means of controlling the charge amount can be enriched, and the electrical performance of the tilted superjunction structure can be adjusted.

[0012] In some embodiments, the charge amount of the first doped portion is balanced with the charge amount of the corresponding portion in the second pillar region.

[0013] By ensuring that the charge amount of the first doped part is balanced with the charge amount of the corresponding part in the second pillar region, it helps to make the tilted superjunction structure have better electrical performance.

[0014] In some implementations, the sidewalls of the superjunction trench have an angle greater than 2° relative to the first direction.

[0015] The embodiments disclosed herein can form super-grooves with a large sidewall slope, reducing the difficulty of the process; at the same time, they can increase the structural styles and are suitable for various demand environments.

[0016] In another aspect, this disclosure also provides a method for manufacturing a tilted superjunction structure, the method comprising: forming a superjunction trench extending into an epitaxial layer along a first direction, wherein the thickness of the epitaxial layer is along the first direction, the sidewalls of the superjunction trench are tilted relative to the first direction, and the epitaxial layer has a first doping type; and forming a plurality of doped portions stacked sequentially along the first direction, the plurality of doped portions filling the superjunction trench, the doped portions having a second doping type, and the doping concentration of the plurality of doped portions decreasing sequentially.

[0017] The method for manufacturing tilted superjunction structures provided in this disclosure has the advantages of low cost and ease of implementation. Based on traditional etching and epitaxial backfilling processes, it is not necessary to excessively control the sidewall slope of the superjunction trench. A tilted superjunction structure with guaranteed performance is achieved through a gradual doping distribution.

[0018] In some implementations, the in-situ doping concentration of the doped portion is controlled according to the sidewall slope of the superjunction trench, and the charge of the doped portion is balanced with the charge of the corresponding portion in the epitaxial layer.

[0019] In this method, in-situ doping can be achieved through epitaxial processes, and the doping concentration can be controlled more precisely. Furthermore, by controlling the in-situ doping concentration of the doped part, the tilted superjunction structure with excellent performance can be effectively manufactured for the actual etching process.

[0020] In some implementations, the sidewalls of the superjunction trench have an angle greater than 2° relative to the first direction.

[0021] The embodiments disclosed herein can form super-grooves with a large sidewall slope, reducing the difficulty of the process; at the same time, they can increase the structural styles and are suitable for various demand environments.

[0022] This disclosure also provides a tilted superjunction structure, which includes: a first pillar region including a plurality of first doped portions stacked along a first direction, the first pillar region having a first doping type; and a second pillar region parallel to the first pillar region, the second pillar region having a second doping type, the interface between the second pillar region and the first pillar region being tilted relative to the first direction, wherein the first doped portion with a smaller projected area along the first direction has a higher doping concentration.

[0023] The tilted superjunction structure provided in this disclosure, although the interface between the first pillar region and the second pillar region is tilted, effectively adjusts the charge difference between the first pillar region and the second pillar region through a gradual doping concentration. This tilted superjunction structure alleviates the charge imbalance problem in the second direction perpendicular to the first direction, resulting in a shorter lateral depletion process during operation and suppression of the final electric field peak, thus improving the blocking performance of the tilted superjunction structure.

[0024] In some embodiments, the second pillar region includes a plurality of second doped portions stacked along the first direction, wherein the second doped portion with a smaller projected area along the first direction has a higher doping concentration.

[0025] By setting doped regions with gradually varying doping concentrations in both the first and second pillar regions, the means of controlling charge can be enriched, and the electrical performance of the tilted superjunction structure can be adjusted more precisely.

[0026] In some implementations, the angle between the interface and the first direction is greater than 2°.

[0027] The embodiments disclosed herein can provide a variety of tilted superjunction structures to suit different needs. The tilted superjunction structures provided have low manufacturing costs and are easy to manufacture.

[0028] This disclosure also provides a semiconductor device comprising: the aforementioned tilted superjunction structure; a first conductive structure located on one side of the tilted superjunction structure along a first direction; and a second conductive structure located on the other side of the tilted superjunction structure along the first direction, electrically connected to the first conductive structure via the tilted superjunction structure.

[0029] The semiconductor device provided in this disclosure has good blocking performance. The manufacturing cost of this semiconductor device is low. Attached Figure Description

[0030] Figure 1 A flowchart illustrating a method for manufacturing a tilted superjunction structure according to an embodiment of this disclosure;

[0031] Figure 2 A schematic diagram of the tilted superjunction structure provided in this embodiment of the disclosure;

[0032] Figure 3 A schematic diagram of the tilted superjunction structure provided in this embodiment of the disclosure;

[0033] Figure 4 A flowchart illustrating a method for manufacturing a tilted superjunction structure according to an embodiment of this disclosure;

[0034] Figure 5 A schematic diagram of the tilted superjunction structure provided in this embodiment of the disclosure;

[0035] Figure 6 Two-dimensional electric field distribution diagram of the tilted superjunction structure provided in this embodiment of the present disclosure;

[0036] Figure 7 Two-dimensional electric field distribution diagram of the superjunction structure in the comparative implementation method;

[0037] Figure 8 for Figure 6 and Figure 7 The electric field variation curve at the mid-vertical axis position;

[0038] Figure 9 for Figure 6 and Figure 7 The electric field variation curve of the horizontal path passing through the center;

[0039] Figure 10 A schematic diagram of the structure of a semiconductor device provided in the embodiments of this disclosure;

[0040] Figure 11 A schematic diagram of the structure of a semiconductor device provided in this embodiment of the disclosure.

[0041] Figure reference numerals: 100, tilted superjunction structure; 1, N-pillar region; 10, first doped region; 11, first first doped region; 12, second first doped region; 13, third first doped region; 2, P-pillar region; 20, second doped region; 21, first second doped region; 22, second second doped region; 23, third second doped region; 3, substrate; 40, Schottky metal layer; 41, current diffusion layer; 42, channel layer; 43, first source contact region; 44, second source contact region; 45, gate; 46, insulating layer; 200, semiconductor device. Detailed Implementation

[0042] To make the above-mentioned objects, features, and advantages of the embodiments of this disclosure more apparent and understandable, specific embodiments of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the embodiments of this disclosure. However, the embodiments of this disclosure can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the embodiments of this disclosure. Therefore, the embodiments of this disclosure are not limited to the specific embodiments disclosed below.

[0043] In the description of the embodiments of this disclosure, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing the embodiments of this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the embodiments of this disclosure.

[0044] In this disclosure, unless otherwise explicitly stated and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0045] Furthermore, the terms "first," "second," and "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. For example, a first doped portion may also be referred to as a second doped portion, and a second doped portion may also be referred to as a first doped portion. In the description of embodiments of this disclosure, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0046] In this disclosure, unless otherwise explicitly specified and limited, the terms "connected," "linked," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; a flexible connection or a rigid connection along at least one direction; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium, or a direct connection with an intermediate medium present; and they can also refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. The terms "installed," "set," "fixed," etc., can be broadly understood as connection. Those skilled in the art can understand the specific meaning of the above terms in this disclosure according to the specific circumstances.

[0047] As used herein, the terms "layer" and "region" refer to a portion of material comprising a region of a certain thickness. A layer can extend horizontally, vertically, and / or along a conical surface. A layer can be a region of uniform or non-uniform continuous structure, the thickness of which perpendicular to the direction of extension may not exceed the thickness of the continuous structure. A layer can comprise multiple layers. The shapes of the various regions and layers in the accompanying drawings, and their relative sizes and positional relationships, are merely illustrative and may deviate from actual dimensions due to manufacturing tolerances or technical limitations, and the design may be adjusted to meet specific requirements.

[0048] See Figure 1 , Figure 1 A method flow diagram for manufacturing a tilted superjunction structure according to an embodiment of this disclosure is shown. The method 1000 for manufacturing a tilted superjunction structure provided in this embodiment of the disclosure includes the following steps S101 to S103.

[0049] Step S101: Forming multiple doped layers. These doped layers can be formed sequentially via epitaxial growth. These doped layers are stacked sequentially along a first direction and each has a first doping type, such as n-type doping. The concentration of the doped layers increases sequentially along the stacking direction. Exemplarily, embodiments of this disclosure can form a gradient doped layer with a gradually increasing concentration. This gradient doped layer can be considered to be formed by stacking a very large number of doped layers, for example, the doping concentration in each lattice layer continuously increases.

[0050] Step S102: Forming a superjunction trench. The superjunction trench can be formed by etching, through which multiple doped layers can be etched, thus obtaining a first pillar region. The first pillar region includes multiple first doped portions stacked sequentially along a first direction. The superjunction trench extends into the multiple doped layers and can therefore be considered parallel to the first pillar region. The sidewalls of the superjunction trench are inclined relative to the first direction. Generally, the superjunction trench has a wide opening and a narrow bottom, while the first pillar region has a narrow top and a wide bottom.

[0051] Step S103: Forming the second pillar region. The second pillar region fills the superjunction trench and may have a shape that is larger at the top and smaller at the bottom. The second pillar region has a second doping type, such as p-type doping. The interface between the second pillar region and the first pillar region may be based on the sidewall of the original superjunction trench.

[0052] The method provided in this disclosure can form a first pillar region with progressively increasing doping concentration, followed by etching and epitaxial backfilling, which can form a tilted superjunction structure with good electrical performance at low cost and simply.

[0053] Combination Figure 2 As shown, Figure 2 An inclined superjunction structure according to an embodiment of the present disclosure is shown. In some embodiments, the inclined superjunction structure 100 may be manufactured by the aforementioned method 1000. Figure 2 The diagram shows the cellular structure of the tilted superjunction structure 100 in the XZ plane, and two adjacent tilted superjunction structures 100 can be approximately mirror-symmetrical.

[0054] For example, a first pillar region is obtained in step S102, which may be an N-pillar region 1. The doping type of the N-pillar region 1 may be n-type, i.e., electronic doping. The material of the N-pillar region 1 may include at least one of silicon carbide, silicon, silicon germanium, germanium, and group III-V compounds such as gallium nitride and gallium arsenide.

[0055] N-pillar region 1 includes a plurality of first doped portions 10 stacked along the Z-axis direction, i.e., the first direction. Exemplarily, a first first doped portion 11, a second first doped portion 12, and a third first doped portion 13 are stacked sequentially from bottom to top along the Z-axis direction. The first first doped portion 11 may have n-type doping, the second first doped portion 12 may have n-type doping, and the third first doped portion 13 may have n+ type doping. Exemplarily, the thickness of each first doped portion 10 may be the same or different.

[0056] In step S103, a second pillar region can be formed, which can be a P-pillar region 2. The doping type of the P-pillar region 2 can be p-type, i.e., hole-type doping. The P-pillar region 2 and the N-pillar region 1 are parallel and can be attached along the X-axis direction, and their interface is inclined relative to the Z-axis direction. For example, the angle between the interface and the Z-axis direction is greater than 2°, in other words, the angle between the interface and the top or bottom surface of the inclined superjunction structure 100 can be less than 88°. Understandably, the angle between the sidewall of the superjunction trench in step S102 and the first direction can be greater than 2°. The range of angles formed by the etching process can be relatively wide.

[0057] In an exemplary embodiment, in step S101, the in-situ doping concentration of the doped layer is controlled according to the sidewall slope of the superjunction trench to be formed. For example, the larger the angle between the interface of the P-pillar region 2 and the N-pillar region 1 relative to the Z-axis direction, the higher the doping concentration of the third first doped portion 13 can be, and the lower the doping concentration of the first first doped portion 11 can be. Through this step, a more charge-balanced P-pillar region 2 and N-pillar region 1 can be obtained.

[0058] Figure 3 A tilted superjunction structure provided by an embodiment of this disclosure is illustrated. In some embodiments, the step of forming the second pillar region, i.e., the P-pillar region 2, includes forming a plurality of second doped portions 20 stacked sequentially along a first direction, wherein the doping concentration of the plurality of second doped portions 20 decreases sequentially. These second doped portions 20 can be formed using a segmented epitaxial filling process. Exemplarily, the thickness of each second doped portion 20 may be the same or different. The thickness of each second doped portion 20 may be the same as the thickness of its opposite first doped portion 10.

[0059] like Figure 3 As shown, these second doped portions 20 may include a first second doped portion 21, a second second doped portion 22, and a third second doped portion 23 stacked sequentially from bottom to top. Exemplarily, the first second doped portion 21 may have p+ type doping, the second second doped portion 22 may have p- type doping, and the third second doped portion 23 may have p- type doping. More second doped portions 20 may be provided in the p-pillar region 2. Exemplarily, embodiments of this disclosure may form gradient doped portions with gradually decreasing concentrations, which can be considered as being formed by stacking a large number of doped portions, for example, the doping concentration in each lattice layer continuously decreases.

[0060] For example, the charge of the first doped portion 10 is balanced with the charge of the corresponding portion in the second pillar region. This embodiment of the present disclosure, by providing multiple first doped portions 10 with varying concentrations along the Z-axis direction, can counteract the charge imbalance in the X-axis direction caused by the tilt of the interface between the two pillar regions, thus achieving local charge balance at multiple cross-sections of the tilted superjunction structure 100 in the Z-axis direction. Furthermore, by providing multiple second doped portions 20, it helps to overcome the charge imbalance and electric field inhomogeneity problems of the tilted superjunction structure 100, where the interface tilt is more pronounced.

[0061] For example, the type of dopant element in in-situ doping can be controlled.

[0062] Figure 4 This disclosure illustrates a method for manufacturing a tilted superjunction structure according to an embodiment of the present disclosure. Exemplarily, this disclosure also provides a method 2000 for manufacturing a tilted superjunction structure. Method 2000 includes the following steps S201 to S202.

[0063] Step S201: Forming a superjunction trench. This superjunction trench extends into the epitaxial layer along a first direction, and the thickness of the epitaxial layer can be along the first direction. The sidewalls of the superjunction trench are inclined relative to the first direction; typically, the trench opening is wider than the bottom. A first pillar region can be obtained based on the epitaxial layer, with a narrower top and a wider bottom. The epitaxial layer has a first doping type, such as n-type doping.

[0064] In step S202, multiple doped portions are formed. These doped portions can be stacked sequentially along a first direction and fill the superjunction trenches. The doped portions can have a second doping type, such as p-type doping. The doping concentration of the multiple doped portions decreases sequentially.

[0065] Figure 5 An inclined superjunction structure provided by an embodiment of this disclosure is illustrated. Exemplarily, Figure 5 The tilted superjunction structure 100 shown can be manufactured by the aforementioned method 2000.

[0066] For example, in step S201, the N-pillar region 1, i.e., the first pillar region, can be obtained based on the epitaxial layer. The formed superjunction trench can penetrate the first pillar region along the Z-axis direction.

[0067] In step S202, three second doped regions 20 can be formed by filling three p-type epitaxial segments. These second doped regions 20 can be referred to as doped regions. The formed P-pillar region 2 is the second pillar region. The P-pillar region 2 may include more second doped regions 20, and the doping concentration of these second doped regions 20 decreases sequentially from bottom to top.

[0068] Exemplarily, these second doped portions 20 may include a first second doped portion 21, a second second doped portion 22, and a third second doped portion 23 stacked sequentially from bottom to top. Exemplarily, the first second doped portion 21 may have p+ type doping, the second second doped portion 22 may have p type doping, and the third second doped portion 23 may have p- type doping. More second doped portions 20 may be provided in the p-pillar region 2. Exemplarily, embodiments of this disclosure may form gradient doped portions with gradually decreasing concentrations, which can be considered as being formed by stacking a large number of doped portions, for example, the doping concentration in each lattice layer continuously decreases.

[0069] The method 2000 for manufacturing a tilted superjunction structure provided in this disclosure can more easily form an epitaxial layer, thereby effectively reducing the charge imbalance in the X-axis direction.

[0070] In step S202, the in-situ doping concentration of the doped portion can be controlled according to the sidewall slope of the superjunction trench, and the charge of the doped portion is balanced with the charge of the corresponding portion in the epitaxial layer. In other words, the charge of the second doped portion 20 is balanced with the charge of the corresponding portion in the N-pillar region 1. This method 2000 can accurately achieve charge balance according to the sidewall slope of the superjunction trench, and fabricate a tilted superjunction structure 100 with good performance and low cost.

[0071] For example, the sidewall of the superjunction trench has an angle greater than 2° relative to the first direction, i.e., the Z-axis direction; in other words, the angle relative to the X-axis direction is less than 88°. This method 2000 has low manufacturing cost and can manufacture tilted superjunction structures 100 of various specifications.

[0072] refer to Figure 2 , Figure 3 and Figure 5 In another aspect, this disclosure provides a tilted superjunction structure. The tilted superjunction structure 100 provided in this disclosure can achieve energization along the Z-axis direction, i.e., a first direction. The tilted superjunction structure 100 includes two pillar regions, specifically a first pillar region and a second pillar region. The two pillar regions are flush along the Z-axis direction and adhere to each other in the X-axis direction. The interface between the two pillar regions is tilted relative to the Z-axis direction or the X-axis direction.

[0073] For example, N-pillar region 1 can be referred to as the first pillar region, and P-pillar region 2 as the second pillar region. At least one pillar region of the tilted superjunction structure 100 includes a plurality of doped portions stacked along a first direction. For example, N-pillar region 1, i.e., the first pillar region, includes a plurality of first doped portions 10 stacked along the Z-axis direction.

[0074] In other embodiments, N-pillar region 1 can be referred to as the second pillar region, and P-pillar region 2 as the first pillar region. For example... Figure 5As shown, the P-pillar region 2 can be considered as a first pillar region, which then includes a plurality of second doped portions 20 stacked along the Z-axis. In this case, the first pillar region has a first doping type of p-type doping, and the second pillar region has a second doping type of n-type doping.

[0075] The first and second pillar regions are side-by-side and can have a centrally symmetrical overall shape. In general, the smaller the projected area along the first direction, the higher the doping concentration of the doped region. For example, as... Figure 2 or Figure 3 As shown, along the Z-axis, the projected area of ​​the third first doped portion 13 is smaller than the projected area of ​​the first first doped portion 11, and the doping concentration of the third first doped portion 13 is greater than the doping concentration of the first first doped portion 11. In other embodiments, such as Figure 3 or Figure 5 As shown, along the Z-axis, the projected area of ​​the first second doped part 21 is smaller than the projected area of ​​the third second doped part 23, and the doping concentration of the first second doped part 21 is greater than the doping concentration of the third second doped part 23.

[0076] For example, the doping concentration of the first doped region 11 is less than the doping concentration of the P-pillar region 2. For example, the doping concentration of the third doped region 23 is less than the doping concentration of the N-pillar region 1.

[0077] Figure 6 The two-dimensional electric field of the tilted superjunction structure provided in this disclosure embodiment is shown, for example... Figure 5 The two-dimensional electric field of the tilted superjunction structure 100 shown; Figure 7 To illustrate the two-dimensional electric field of the superjunction structure in the comparative implementation method. For example... Figure 6 and Figure 7 As shown, due to the tilted interface of the pillar region, the peak electric field of the tilted superjunction structure is located at the center, rather than at the top of the conventional superjunction structure. The segmented-doped tilted superjunction structure 100 has a smaller central electric field intensity compared to the undoped tilted superjunction structure.

[0078] Figure 8 for Figure 6 and Figure 7 The electric field variation curve at the middle vertical axis position, Figure 9 for Figure 6 and Figure 7 The electric field variation curve of a horizontal path passing through the center. For example... Figures 6 to 9 As shown, by reducing the doping concentration of the third second doped portion 23, the tilted superjunction structure 100 provided in this embodiment of the present disclosure can have a smaller central electric field spike and better breakdown voltage performance.

[0079] The tilted superjunction structure provided in this disclosure, by setting segmented, gradually doped doped portions, helps to reduce the problem of lateral charge unevenness caused by the tilt of the pillar interface. This tilted superjunction structure has a fast lateral depletion rate, a shorter process, a lower peak central electric field, and improved blocking performance. This tilted superjunction structure has good electrical performance, ensuring normal conduction performance; furthermore, the manufacturing cost is controllable, it is not necessary to pursue a perfectly vertical pillar interface, and the interface can have a curvature.

[0080] refer to Figure 3 In the tilted superjunction structure 100 provided in this embodiment, the second pillar region includes a plurality of second doped portions stacked along the first direction, and the second doped portion with a smaller projected area along the first direction has a higher doping concentration.

[0081] For example, the angle between the interface of the first column region and the second column region relative to the first direction is greater than 2°.

[0082] Figure 10 A semiconductor device according to an embodiment of the present disclosure is shown. The semiconductor device 200 may include a superjunction trench insulated-gate field-effect transistor. The semiconductor device 200 may include a first conductive structure, a tilted superjunction structure 100, and a second conductive structure stacked sequentially along the Z-axis.

[0083] like Figure 10 As shown, the first conductive structure is located below the tilted superjunction structure 100 and can be substrate 3. Substrate 3 may have n+ type doping. The N-pillar region 1 may be epitaxially grown based on substrate 3.

[0084] The second conductive structure may include a current diffusion layer 41, a channel layer 42, and a first source contact region 43 stacked sequentially. The current diffusion layer 41 and the first source contact region 43 may have a first doping type, and the channel layer 42 may have a second doping type. The second conductive structure also includes an insulating gate structure extending from the top to the tilted superjunction structure 100, the insulating gate structure including a gate 45 and an insulating layer 46 located between the gate 45 and the remaining layers. The second conductive structure may also include a second source contact region 44, located on the side of the first source contact region 43 opposite to the insulating gate structure, and electrically connected to the channel layer 42.

[0085] The substrate 3 can be electrically connected to the first source contact region 43 via the tilted superjunction structure 100.

[0086] The semiconductor device provided in this disclosure has good electrical performance and good blocking performance.

[0087] Figure 11A semiconductor device according to an embodiment of the present disclosure is illustrated. The semiconductor device 200 may include a superjunction Schottky diode. The semiconductor device 200 includes a first conductive structure, a tilted superjunction structure 100, and a second conductive structure stacked sequentially along the Z-axis. The first conductive structure may include a substrate 3. The second conductive structure may include a Schottky metal layer 40.

[0088] For example, the semiconductor device also includes a circuit that can be electrically connected to the first conductive structure and the second conductive structure.

[0089] The technical features of the above-disclosed embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above 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.

[0090] In the embodiments disclosed above, unless otherwise explicitly specified and limited, the execution order of each step is not restricted. For example, they can be executed in parallel or sequentially in different orders. The sub-steps of each step can also be executed alternately. Various forms of processes described above can be used, and steps can be reordered, added, or deleted, as long as the desired result of the technical solution provided by the embodiments of this disclosure can be achieved, and no limitations are imposed herein.

[0091] The embodiments disclosed above merely illustrate several implementation methods of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of patent protection for the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the inventive concept, and these all fall within the scope of patent protection claimed by the present invention. Therefore, the scope of patent protection for the present invention should be determined by the appended claims.

Claims

1. A method for manufacturing tilted superjunction structures, characterized in that, include: A superjunction trench is formed extending into the epitaxial layer along a first direction, wherein the thickness of the epitaxial layer is along the first direction, the sidewalls of the superjunction trench are inclined relative to the first direction, and the epitaxial layer is electronically doped; and Multiple doped portions are formed and stacked sequentially along the first direction, the multiple doped portions filling the superjunction trench, wherein the in-situ doping concentration of the doped portions is controlled according to the sidewall slope of the superjunction trench, the doped portions have hole-type doping, the doping concentration of the multiple doped portions decreases sequentially, and the charge of the doped portions is balanced with the charge of the corresponding portion in the epitaxial layer.

2. The method for manufacturing a tilted superjunction structure according to claim 1, wherein, The sidewall of the superjunction trench has an angle greater than 2° relative to the first direction.

3. The method for manufacturing a tilted superjunction structure according to claim 1 or 2, wherein, It also includes: forming doped layers sequentially by epitaxy to form a gradient doped layer with gradually increasing concentration, wherein the gradient doped layer is the epitaxial layer; The step of forming the superjunction trench includes: obtaining a first pillar region based on the formed multiple doped layers, the first pillar region including multiple first doped portions stacked sequentially along the first direction; the multiple doped portions are multiple second doped portions of the second pillar region.

4. An inclined superjunction structure, characterized in that, Manufactured by the method of any one of claims 1 to 3.

5. A semiconductor device, characterized in that, include: A first conductive structure, a tilted superjunction structure as described in claim 4, and a second conductive structure are stacked sequentially along a first direction, wherein the second conductive structure is electrically connected to the first conductive structure through the tilted superjunction structure.

6. An inclined superjunction structure, characterized in that, include: The first pillar region includes a plurality of first doped portions stacked along a first direction, and the first pillar region has electronic doping; and A second pillar region, parallel to the first pillar region, includes a plurality of second doped portions stacked along the first direction. The second pillar region has hole-type doping, and the interface between the second pillar region and the first pillar region is inclined relative to the first direction. The first doped portion with a smaller projected area along the first direction has a higher doping concentration, and the second doped portion with a smaller projected area along the first direction has a higher doping concentration. The charge of the first doped portion is balanced with the charge of the corresponding portion in the second pillar region.

7. The tilted superjunction structure according to claim 6, wherein, The angle between the interface and the first direction is greater than 2°.

8. A semiconductor device, characterized in that, include: A first conductive structure, an inclined superjunction structure as described in any one of claims 6 to 7, and a second conductive structure are stacked sequentially along a first direction, wherein the second conductive structure is electrically connected to the first conductive structure through the inclined superjunction structure.

9. The semiconductor device according to claim 8, wherein, The first conductive structure includes a substrate, and the second conductive structure includes an insulating gate structure and a current diffusion layer, a channel layer and a first source contact region stacked sequentially. The insulating gate structure extends through the current diffusion layer, the channel layer, and the first source contact region.

10. The semiconductor device according to claim 9, wherein, The insulating grid structure is located in the second column region.

11. The semiconductor device according to claim 8, wherein, The first conductive structure includes a substrate, and the second conductive structure includes a Schottky metal layer.

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