Diode structure

Abstract

The utility model provides a diode structure. The diode structure comprises: a semiconductor substrate having a first surface; the first doped region extends into the semiconductor substrate from the first surface and is provided with a plurality of first preset regions located in the first surface, every two of the plurality of first preset regions are arranged at intervals, and a graph defined by side lines of the first preset regions in the first surface is dumbbell-shaped; the second doped region extends into the semiconductor substrate from the first surface and is provided with a second preset region located in the first surface, the second preset region is a region, except the first preset region, in the first surface, and at least one of the first doped region and the second doped region is different from the semiconductor substrate in doping type. According to the invention, the problem that the anti-surge capability of a diode in the prior art is poor is solved, and the effect of injection balance under the surge current working condition and the rated current working condition of the diode structure is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductors, and particularly to a diode structure. Background Art

[0002] A diode is a basic semiconductor device with unidirectional conductivity, and its core structure is formed by combining a P-type semiconductor and an N-type semiconductor to form a PN junction.

[0003] In traditional designs, the P region and the N region are side-by-side strips (long and narrow rectangular regions), and the contact interface (PN junction) between the two extends along the length direction of the strip, with a relatively narrow lateral width and a small effective PN junction contact area. Under surge conditions, the surge current will laterally diffuse across the entire strip width. However, due to the limitation of the narrow lateral width, the surge current cannot be evenly distributed and is forced to concentrate and pass through a limited lateral junction region. This concentration effect results in poor surge resistance of the diode, thereby causing reliability problems. Summary of the Utility Model

[0004] The main purpose of the utility model is to provide a diode structure to solve the problem of poor surge resistance of diodes in the prior art.

[0005] To achieve the above purpose, a diode structure is provided, including: a semiconductor substrate having a first surface; a first doping region extending from the first surface into the semiconductor substrate and having a plurality of first preset regions located in the first surface, the plurality of first preset regions being spaced apart from each other in pairs, and the outline of the first preset regions enclosing a dumbbell-shaped figure in the first surface; a second doping region extending from the first surface into the semiconductor substrate and having a second preset region located in the first surface, the second preset region being the region in the first surface other than the first preset regions, and at least one of the first doping region and the second doping region having a doping type different from that of the semiconductor substrate.

[0006] Optionally, the dumbbell shape has a major axis and a minor axis perpendicular to each other and includes two wide regions and a narrow region connecting the two wide regions, the two wide regions being symmetric about the extension line of the minor axis of the dumbbell shape, and the connection line of the two wide regions coinciding with the extension line of the major axis of the dumbbell shape; the plurality of first preset regions include a plurality of first sub-preset regions and a plurality of second sub-preset regions alternately distributed in a first direction, the outline of the first sub-preset regions enclosing a first dumbbell shape in the first surface, and the outline of the second sub-preset regions enclosing a second dumbbell shape in the first surface; the extension lines of the minor axes of the plurality of first dumbbell shapes coincide in the first direction, the extension lines of the major axes of the plurality of second dumbbell shapes coincide in the first direction, and the extension lines of the minor axes of the plurality of first dumbbell shapes coincide with the extension lines of the major axes of the plurality of second dumbbell shapes in the first direction.

[0007] Optionally, the multiple first preset regions further include multiple first sub-preset regions and multiple second sub-preset regions that are alternately distributed in the second direction. The extension lines of the major axes of the multiple first dumbbell shapes coincide in the second direction, the extension lines of the minor axes of the multiple second dumbbell shapes coincide in the second direction, and the extension lines of the major axes of the multiple first dumbbell shapes coincide with the extension lines of the minor axes of the multiple second dumbbell shapes in the second direction.

[0008] Optionally, the dumbbell shape has a major axis and a minor axis that are perpendicular to each other and includes two wide regions and a narrow region connecting the two wide regions. The two wide regions are symmetric about the extension line of the minor axis of the dumbbell shape, and the connection line of the two wide regions coincides with the extension line of the major axis of the dumbbell shape. The multiple first preset regions include multiple third sub-preset regions and multiple fourth sub-preset regions that are alternately distributed in the first direction. The dumbbell shape formed by the side edges of the third sub-preset region in the first surface is the third dumbbell shape, and the dumbbell shape formed by the side edges of the fourth sub-preset region in the first surface is the fourth dumbbell shape. The extension lines of the minor axes of the multiple third dumbbell shapes coincide in the first direction, the extension lines of the minor axes of the multiple fourth dumbbell shapes coincide in the first direction, and the connection line of the center points of the wide regions of two adjacent fourth dumbbell shapes in the first direction coincides with the extension line of the minor axis of the multiple third dumbbell shapes.

[0009] Optionally, the multiple first preset regions further include multiple third sub-preset regions and multiple fourth sub-preset regions that are alternately distributed in the second direction. The extension lines of the major axes of the multiple third dumbbell shapes coincide in the second direction, and the extension lines of the major axes of the multiple fourth dumbbell shapes coincide in the second direction.

[0010] Optionally, the doping types of the first doping region and the second doping region are opposite; or, the doping types of the first doping region and the second doping region are the same.

[0011] Optionally, when the doping types of the first doping region and the second doping region are opposite, the doping type of the semiconductor substrate and the first doping region may be the same or different.

[0012] Optionally, the diode structure further includes: the dumbbell shape includes two wide regions and a narrow region connecting the two wide regions; when the doping type of the first doping region is P type and the doping types of the second doping region and the semiconductor substrate are both N type, the first doping region further has a third preset region located in the first preset region, and the third preset region is located in the wide region; an ohmic contact region extends from the third preset region into the first doping region. The doping type of the ohmic contact region is the same as that of the first doping region, and the doping concentration of the ohmic contact region is greater than that of the first doping region.

[0013] Optionally, when the doping type of the second doping region is P-type and the doping types of the first doping region and the semiconductor substrate are both N-type, the diode structure further includes: an ohmic contact region extending from the second preset region into the second doping region. The doping type of the ohmic contact region is the same as that of the second doping region, and the doping concentration of the ohmic contact region is greater than that of the second doping region.

[0014] Optionally, when the doping types of the first doping region and the second doping region are the same, the doping concentrations of the first doping region and the second doping region are different.

[0015] Applying the technical solution of the present utility model, a diode structure is provided. The diode structure includes a semiconductor substrate, a first doped region, and a second doped region. Among them, the semiconductor substrate has a first surface. The first doped region and the second doped region both extend from the first surface into the semiconductor substrate. The first doped region has a plurality of first preset regions located in the first surface, and the plurality of first preset regions are arranged at intervals in pairs. The figure formed by the side lines of the first preset regions in the first surface is dumbbell-shaped; the second doped region has a second preset region located in the first surface, and the second preset region is the region in the first surface except the first preset region. At least one of the first doped region and the second doped region has a doping type different from that of the semiconductor substrate. The present application has the following beneficial effects: When the figure formed by the side lines of the first preset regions in the first surface is dumbbell-shaped and the second preset region surrounds each first preset region, because the dumbbell shape has a morphology with wide ends and a narrow middle, the lateral dimension or area of only a part of the first doped region corresponding to the end regions of the dumbbell shape in the first doped region can be increased, while the lateral dimension or area of a part of the first doped region corresponding to the middle region of the dumbbell shape in the first doped region is reduced. Thus, the lateral dimension or area of a part of the second doped region corresponding to the middle region of the dumbbell shape in the second doped region is also increased. The region with a larger lateral dimension will increase the carrier transmission area, allowing more carriers to pass through simultaneously, reducing the resistance per unit area, providing a lower resistance path, and enabling the electric field lines to naturally tend to flow along the region with a larger lateral dimension, forming multiple parallel low-resistance paths in the diode. Therefore, through the present application, under stable operating conditions (rated current), the diode structure can also have good output current capacity; at the same time, even under surge conditions, the surge current can be diffused through the region with a larger lateral dimension to adjust the current path, which helps to disperse the electric field intensity, enables the electric field lines to be more evenly distributed in the diode, allows the surge current under surge conditions to flow uniformly in a wider region, rather than concentrating on a single straight path (such as traditional long-strip P regions and N regions), reduces the current density in each local region, and improves the surge resistance of the diode. In summary, through the present application, the problem of poor surge resistance of diodes in the prior art is solved, and the effect of achieving injection balance between the surge current condition and the rated current condition of the diode structure is achieved. Description of the Drawings

[0016] The specification drawings forming a part of the present utility model are used to provide a further understanding of the present utility model. The schematic embodiments of the present utility model and their descriptions are used to explain the present utility model and do not constitute an improper limitation of the present utility model. In the drawings:

[0017] Figure 1 Shows a cross-sectional schematic diagram of a semiconductor substrate in a diode structure according to an embodiment of the present utility model;

[0018] Figure 2 Shows a layout schematic diagram of a first doping region and a second doping region in a first surface in a diode structure according to a first embodiment of the present invention;

[0019] Figure 3 Shows a layout schematic diagram of a first doping region and a second doping region in a first surface in a diode structure according to a second embodiment of the present invention;

[0020] Figure 4 Shows a layout schematic diagram of a first doping region and a second doping region in a first surface in a diode structure according to a third embodiment of the present invention;

[0021] Figure 5 Shows a layout schematic diagram of a first doping region and a second doping region in a first surface in a diode structure according to a fourth embodiment of the present invention;

[0022] Figure 6 Shows a layout schematic diagram of a first doping region and a second doping region in a first surface in a diode structure according to a fifth embodiment of the present invention;

[0023] Figure 7 Shows a layout schematic diagram of a first doping region and a second doping region in a first surface in a diode structure according to a sixth embodiment of the present invention.

[0024] Wherein, the above-mentioned drawings include the following reference numerals:

[0025] 10. Semiconductor substrate; 20. Second doping region; 30. First doping region; 301. Narrow region; 302. Wide region; 310. First dumbbell shape; 320. Second dumbbell shape; 330. Third dumbbell shape; 340. Fourth dumbbell shape; 40. Ohmic contact region. Detailed implementation manners

[0026] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other. The present invention will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0027] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0028] It should be noted that the terms "first", "second", etc. in the description, claims and above-mentioned drawings of the present utility model are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that such data used can be interchanged under appropriate circumstances, so as to implement the embodiments of the present utility model described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0029] As described in the background art, in the traditional design, the P region and the N region of the diode are side-by-side strips (long and narrow rectangular regions), and the contact interface (PN junction) between the two extends along the length direction of the strip, with a relatively narrow lateral width and a small effective PN junction contact area. Under surge conditions, the surge current will laterally diffuse across the entire strip width. However, due to the limitation of the narrow lateral width, the surge current cannot be evenly distributed and is forced to concentrate and pass through a limited lateral junction region. This concentration effect results in poor surge resistance of the diode, thus causing reliability problems. To solve the problem of poor surge resistance of the diode in the prior art.

[0030] In some alternative embodiments, a diode structure is provided, as Figure 1 shown, comprising: a semiconductor substrate 10 having a first surface; a first doping region 30 extending from the first surface into the semiconductor substrate 10 and having a plurality of first preset regions located in the first surface, the plurality of first preset regions being spaced apart from each other in pairs, and the figure formed by the side lines of the first preset regions in the first surface being a dumbbell shape; a second doping region 20 extending from the first surface into the semiconductor substrate 10 and having a second preset region located in the first surface, the second preset region being the region in the first surface other than the first preset region, and at least one of the first doping region 30 and the second doping region 20 having a doping type different from that of the semiconductor substrate.

[0031] Optionally, the above-mentioned semiconductor substrate 10 includes a substrate and an epitaxial layer stacked in a direction perpendicular to the first surface, and the surface of the epitaxial layer away from the substrate is the above-mentioned first surface. Further, the above-mentioned epitaxial layer may include a buffer layer, a drift layer and a JFET layer stacked, and the buffer layer is located between the drift layer and the substrate. On this basis, when the first doping region 30 extends from the first surface into the semiconductor substrate 10, the first doping region 30 may extend from the first surface into the drift layer; the second doping region 20 may extend from the first surface into the JFET layer.

[0032] Optionally, the above-mentioned substrate is a silicon substrate or a silicon carbide substrate.

[0033] Optionally, the doping concentration of the above-mentioned JFET layer is 1e14~3e16 cm -3 , so as to reduce the on-resistance of the device; the doping concentration of the above-mentioned drift layer is 1e14~1e16 cm -3 , so as to improve the breakdown voltage of the device and ensure the breakdown voltage requirement of the device; the doping concentration of the above-mentioned buffer layer is 5e17~1e19 cm -3 , so as to effectively increase the electric field slope inside the device and achieve electric field termination.

[0034] Specifically, the doping type of the above-mentioned semiconductor substrate 10 can be N-type. Further, in the case where the doping type of the above-mentioned semiconductor substrate 10 can be N-type, the doping types of the above-mentioned buffer layer, the above-mentioned drift layer, and the above-mentioned JFET layer can all be N-type.

[0035] Specifically, the first doping region 30 is an integral whole that is connected in the semiconductor substrate 10, and it presents as a plurality of first preset regions that are spaced apart from each other in the first surface, so that the first doping region 30 has a plurality of first preset regions located in the first surface. Similarly, the second doping region 20 is an integral whole that is connected in the semiconductor substrate 10, and it presents as a second preset region that is connected and surrounds each first preset region in the first surface, so that the second doping region 20 has a second preset region located in the first surface, and the second preset region is the region in the first surface except for the plurality of first preset regions.

[0036] Specifically, the doping types of the first doping region 30 and the second doping region 20 can be the same; or, the doping types of the first doping region 30 and the second doping region 20 can be opposite. It should be noted here that in the case where the doping types of the first doping region 30 and the second doping region 20 are the same, the doping type of the semiconductor substrate 10 is different from the doping types of the first doping region 30 and the second doping region 20 respectively; in the case where the doping types of the first doping region 30 and the second doping region 20 are opposite, the doping type of the semiconductor substrate 10 can be opposite to the doping type of the first doping region 30, or the doping type of the semiconductor substrate 10 can be opposite to the doping type of the second doping region 20.

[0037] Specifically, in the case where the doping types of the first doping region 30 and the second doping region 20 can be the same and have different doping concentrations, the doping types of the first doping region 30 and the second doping region 20 can both be P-type, and the doping concentration of the first doping region 30 can be greater than the doping concentration of the second doping region 20; or, the doping types of the first doping region 30 and the second doping region 20 can both be P-type, and the doping concentration of the first doping region 30 can be less than the doping concentration of the second doping region 20.

[0038] Specifically, when the doping types of the first doping region 30 and the second doping region 20 can be opposite, the doping type of the first doping region 30 can be N-type, and the doping type of the second doping region 20 can be P-type; or, the doping type of the first doping region 30 can be P-type, and the doping type of the second doping region 20 can be N-type. The magnitude relationship between the doping concentrations of the first doping region 30 and the second doping region 20 is not specifically limited.

[0039] Optionally, the areas of the multiple first preset regions are the same. Further, the shapes of the multiple dumbbell shapes corresponding to the multiple first preset regions can be the same and the sizes can be consistent. It can be understood that since the areas of the above-mentioned first preset regions and the shapes and sizes of the dumbbell shapes corresponding to each first preset region are all the same, the injection efficiencies of the respective regions in the first doping region corresponding to the multiple first preset regions one by one are similar, enabling the current to be more evenly distributed in the first doping region.

[0040] Specifically, the dumbbell shape has a morphology with wider ends and a narrower middle in the first surface, so that the wider regions at both ends of the dumbbell shape can be regarded as the two wide regions 302 of the dumbbell shape, and the narrower region in the middle can be regarded as the narrow region 301 of the dumbbell shape.

[0041] In the above-described embodiments, when the figure formed by the side lines of the first preset region on the first surface is dumbbell-shaped and the second preset region surrounds each first preset region, since the dumbbell has a morphology with wide ends and a narrow middle, the lateral dimension or area of only the part of the first doping region corresponding to the end regions of the dumbbell in the first doping region can be increased, while the lateral dimension or area of the part of the first doping region corresponding to the middle region of the dumbbell in the first doping region is decreased. As a result, the lateral dimension or area of the part of the second doping region corresponding to the middle region of the dumbbell in the second doping region is also increased. The region with a larger lateral dimension will increase the carrier transmission area, allowing more carriers to pass through simultaneously, reducing the resistance per unit area, providing a lower resistance path, and enabling the electric field lines to naturally tend to flow along the region with a larger lateral dimension, forming multiple parallel low-resistance paths in the diode. Thus, through the present application, even under stable operating conditions (rated current), the diode structure can also have good output current capacity. At the same time, even under surge conditions, the surge current can be diffused through the region with a larger lateral dimension to adjust the current path, which helps to disperse the electric field intensity, making the electric field lines more evenly distributed in the diode, enabling the surge current under surge conditions to flow uniformly in a wider region rather than concentrating on a single straight path (such as the traditional long-strip P region and N region), reducing the current density in each local region, and improving the surge resistance of the diode. In summary, through the present application, the problem of poor surge resistance of diodes in the prior art is solved, and the injection balance of the diode structure under surge current conditions and rated current conditions is achieved.

[0042] In some alternative embodiments, as Figure 2 , Figure 3 and Figure 4 shown by the dashed boxes in, the dumbbell has a major axis and a minor axis that are perpendicular to each other and includes two wide regions 302 and a narrow region 301 connecting the two wide regions 302. The two wide regions 302 are symmetric about the extension line of the minor axis of the dumbbell, and the connection line of the two wide regions 302 coincides with the extension line of the major axis of the dumbbell. The multiple first preset regions include multiple first sub-preset regions and multiple second sub-preset regions that are alternately distributed in the first direction A. The figure formed by the side lines of the first sub-preset region on the first surface is the first dumbbell 310, and the figure formed by the side lines of the second sub-preset region on the first surface is the second dumbbell 320. The extension lines of the minor axes of the multiple first dumbbells 310 coincide in the first direction A, the extension lines of the major axes of the multiple second dumbbells 320 coincide in the first direction A, and the extension lines of the minor axes of the multiple first dumbbells 310 coincide with the extension lines of the major axes of the multiple second dumbbells 320 in the first direction A.

[0043] In other words, multiple first dumbbells 310 corresponding one-to-one to multiple first sub-preset regions and multiple second dumbbells 320 corresponding one-to-one to multiple second sub-preset regions can be arranged side by side along the first direction A. The first dumbbells 310 corresponding to the first sub-preset regions can be arranged longitudinally, while the second dumbbells 320 corresponding to the second sub-preset regions can be arranged horizontally. There is a second sub-preset region corresponding to a second dumbbell 320 between two first sub-preset regions corresponding to two adjacent first dumbbells 310 one-to-one in the first direction A (there is a second dumbbell 320 corresponding to a second sub-preset region between two first dumbbells 310 corresponding to two adjacent first sub-preset regions one-to-one in the first direction A). The extension line of the short axis of each first dumbbell 310 coincides with the extension line of the long axis of each second dumbbell 320 in the first direction A.

[0044] Specifically, the shapes and sizes of the above-mentioned dumbbells, the above-mentioned first dumbbells 310, and the above-mentioned second dumbbells 320 can be the same.

[0045] Specifically, the first dumbbell 310 has a morphology with wider ends and a narrower middle in the first surface. Thus, the wider regions at both ends of the first dumbbell 310 can be regarded as two wide regions 302 of the first dumbbell 310, and the narrower region in the middle can be regarded as the narrow region 301 of the first dumbbell 310. The second dumbbell 320 has a morphology with wider ends and a narrower middle in the first surface. Thus, the wider regions at both ends of the second dumbbell 320 can be regarded as two wide regions 302 of the second dumbbell 320, and the narrower region in the middle can be regarded as the narrow region 301 of the second dumbbell 320.

[0046] In the above-mentioned embodiment, both the first dumbbell 310 and the second dumbbell 320 have two wide regions 302 and a narrow region 301 connecting the two wide regions 302. The narrow region 301 of the first dumbbell 310 corresponding to the first sub-preset region is aligned with the wide region 302 of the second dumbbell 320 corresponding to the second preset sub-region in the first direction A, which can further improve the distribution of charges in the first direction A, contribute to the redistribution of charges in the first direction A, reduce the accumulation of charges on a certain path, and further enhance the surge resistance of the diode.

[0047] In some alternative embodiments, as Figure 2 、 Figure 3 and Figure 4 shown, the multiple first preset regions further include multiple first sub-preset regions and multiple second sub-preset regions that are alternately distributed along the second direction B. The extension lines of the long axes of the multiple first dumbbells 310 coincide in the second direction B, the extension lines of the short axes of the multiple second dumbbells 320 coincide in the second direction B, and the extension lines of the long axes of the multiple first dumbbells 310 coincide with the extension lines of the short axes of the multiple second dumbbells 320 in the second direction B.

[0048] Specifically, multiple first dumbbells 310 corresponding to multiple first sub-preset regions and multiple second dumbbells 320 corresponding to multiple second sub-preset regions can also be arranged side by side along the second direction B. The first dumbbells 310 corresponding to the first sub-preset regions can be arranged longitudinally, while the second dumbbells 320 corresponding to the second sub-preset regions can be arranged horizontally. There is a second sub-preset region corresponding to the second dumbbell 320 between two first sub-preset regions corresponding to two adjacent first dumbbells 310 in the second direction B (there is a second dumbbell 320 corresponding to the second sub-preset region between two first dumbbells 310 corresponding to two adjacent first sub-preset regions in the second direction B). The extension line of the long axis of each first dumbbell 310 coincides with the extension line of the short axis of each second dumbbell 320 in the second direction B.

[0049] In the above embodiment, the wide region 302 of the first dumbbell 310 corresponding to the first sub-preset region is aligned with the narrow region 301 of the second dumbbell 320 corresponding to the second sub-preset region in the second direction B, which can further improve the distribution of charges in the second direction B, contribute to the redistribution of charges in the second direction B, reduce the accumulation of charges on a certain path, and further enhance the surge resistance of the diode.

[0050] In addition, as Figure 2 、 Figure 3 and Figure 4 shown, in some embodiments, the narrow region 301 of the first dumbbell 310 corresponding to the first sub-preset region can be aligned with the wide region 302 of the second dumbbell 320 corresponding to the second preset sub-region in the first direction A. At the same time, the wide region 302 of the first dumbbell 310 corresponding to the first sub-preset region can also be aligned with the narrow region 301 of the second dumbbell 320 corresponding to the second sub-preset region in the second direction B, thereby contributing to the redistribution of charges in both the first direction A and the second direction B, reducing the accumulation of charges on a certain path, and further enhancing the surge resistance of the diode.

[0051] In some other alternative embodiments, as Figure 5 、 Figure 6 and Figure 7As shown by the dashed box in [description], the dumbbell shape has a major axis and a minor axis perpendicular to each other and includes two wide regions 302 and a narrow region 301 connecting the two wide regions 302. The two wide regions 302 are symmetric along the extension line of the minor axis of the dumbbell shape, and the line connecting the two wide regions 302 coincides with the extension line of the major axis of the dumbbell shape; the plurality of first preset regions include a plurality of third sub-preset regions and a plurality of fourth sub-preset regions alternately distributed along the first direction A. The dumbbell shape formed by the side lines of the third sub-preset regions on the first surface is the third dumbbell shape 330, and the dumbbell shape formed by the side lines of the fourth sub-preset regions on the first surface is the fourth dumbbell shape 340; the extension lines of the minor axes of the plurality of third dumbbell shapes 330 coincide in the first direction A, and the extension lines of the minor axes of the plurality of fourth dumbbell shapes 340 coincide in the first direction A, and the line connecting the central points of the wide regions 302 of two adjacent fourth dumbbell shapes 340 in the first direction A coincides with the extension line of the minor axis of the plurality of third dumbbell shapes 330.

[0052] Specifically, the third dumbbell shape 330 has a morphology with wider ends and a narrower middle on the first surface. Thus, the relatively wider regions at both ends of the third dumbbell shape 330 can be regarded as the two wide regions 302 of the third dumbbell shape 330, and the relatively narrower region in the middle can be regarded as the narrow region 301 of the third dumbbell shape 330. The fourth dumbbell shape 340 has a morphology with wider ends and a narrower middle on the first surface. Thus, the relatively wider regions at both ends of the fourth dumbbell shape 340 can be regarded as the two wide regions 302 of the fourth dumbbell shape 340, and the relatively narrower region in the middle can be regarded as the narrow region 301 of the fourth dumbbell shape 340.

[0053] In other words, the plurality of third dumbbell shapes 330 corresponding one-to-one to the plurality of third sub-preset regions and the plurality of fourth dumbbell shapes 340 corresponding one-to-one to the plurality of fourth sub-preset regions can be arranged side by side along the first direction A. It should be noted that the third dumbbell shape 330 corresponding to the third sub-preset region and the fourth dumbbell shape 340 corresponding to the fourth sub-preset region can both be arranged longitudinally. In addition, the extension lines of the minor axes of the plurality of third dumbbell shapes 330 corresponding one-to-one to the plurality of third sub-preset regions arranged side by side along the first direction A are parallel to the extension lines of the minor axes of the plurality of fourth dumbbell shapes 340 corresponding one-to-one to the plurality of fourth sub-preset regions, and the narrow region 301 of the third dumbbell shape 330 corresponding to the third sub-preset region is aligned with the wide region 302 of the fourth dumbbell shape 340 corresponding to the fourth sub-preset region in the first direction A.

[0054] Specifically, the shapes and sizes of the above-mentioned dumbbell shape, the above-mentioned third dumbbell shape 330, and the above-mentioned fourth dumbbell shape 340 can be the same.

[0055] In the above-described embodiments, the third dumbbell-shaped portion 330 and the fourth dumbbell-shaped portion 340 each have two wide regions 302 and a narrow region 301 connecting the two wide regions 302. The narrow region 301 of the third dumbbell-shaped portion 330 corresponding to the third sub-preset region is aligned with the wide region 302 of the fourth dumbbell-shaped portion 340 corresponding to the fourth preset sub-region in the first direction A. This can further improve the distribution of charges in the first direction A, contribute to the redistribution of charges in the first direction A, reduce the accumulation of charges on a certain path, and further enhance the surge resistance of the diode.

[0056] Further, as Figure 5 , Figure 6 and Figure 7 shown, in some alternative embodiments, the plurality of first preset regions further include a plurality of third sub-preset regions and a plurality of fourth sub-preset regions that are alternately distributed along the second direction B. The extension lines of the major axes of the plurality of third dumbbell-shaped portions 330 coincide in the second direction B, and the extension lines of the major axes of the plurality of fourth dumbbell-shaped portions 340 coincide in the second direction B.

[0057] Specifically, the plurality of third dumbbell-shaped portions 330 corresponding to the plurality of third sub-preset regions may also be arranged side by side along the second direction B, and the plurality of fourth dumbbell-shaped portions 340 corresponding to the fourth sub-preset regions may also be arranged side by side along the second direction B. Moreover, the extension line of the major axis of each third dumbbell-shaped portion 330 is parallel to the extension line of the major axis of each fourth dumbbell-shaped portion 340 in the second direction B. It should be noted that both the third dumbbell-shaped portion 330 corresponding to the third sub-preset region and the fourth dumbbell-shaped portion 340 corresponding to the fourth sub-preset region can be arranged longitudinally.

[0058] In the above-described embodiments, both the wide region 302 and the narrow region 301 of the third dumbbell-shaped portion 330 corresponding to the third sub-preset region are aligned with the wide region 302 and the narrow region 301 of the adjacent third dumbbell-shaped portion 330 corresponding to the third sub-preset region in the second direction B. Both the wide region 302 and the narrow region 301 of the fourth dumbbell-shaped portion 340 corresponding to the fourth sub-preset region are aligned with the wide region 302 and the narrow region 301 of the adjacent fourth dumbbell-shaped portion 340 corresponding to the fourth sub-preset region in the second direction B. Combining the alignment of the narrow region 301 of the third dumbbell-shaped portion 330 corresponding to the third sub-preset region with the wide region 302 of the fourth dumbbell-shaped portion 340 corresponding to the fourth preset sub-region in the first direction A can provide more low-resistance paths in the diode to better adjust the current path, enabling the surge current under surge conditions to flow more uniformly in a wider area, thereby further improving the surge resistance of the diode.

[0059] In some alternative embodiments, when the doping types of the first doping region 30 and the second doping region 20 are opposite, the doping type of the semiconductor substrate 10 may be the same as or different from that of the first doping region 30.

[0060] Specifically, as shown in Figure 2 , Figure 3 , Figure 5 and Figure 6 , when the doping type of the semiconductor substrate 10 can be N-type, the doping type of the first doping region 30 can be N-type, and the doping type of the second doping region 20 can be P-type; or, as shown in Figure 2 , Figure 4 , Figure 5 and Figure 7 , when the doping type of the semiconductor substrate 10 is N-type, the doping type of the first doping region 30 can be P-type, and the doping type of the second doping region 20 can be N-type. It can be understood that the diode structure provided by this embodiment can be a hybrid PIN Schottky diode structure (JBS diode).

[0061] In the above embodiment, as shown in Figures 2 to 7 , when the doping type of the first doping region 30 is N-type, the first doping region 30 can be the Schottky region in the diode structure, and the second doping region 20 can be the junction barrier region in the diode structure; when the doping type of the second doping region 20 is N-type, the second doping region 20 can be the Schottky region in the diode structure, and the first doping region 30 can be the junction barrier region in the diode structure. On this basis, the junction barrier region includes a wide junction barrier region with a larger size in the first direction A (lateral direction) and a narrow junction barrier region with a smaller size in the first direction A (lateral direction). The wide junction barrier region increases the ohmic contact area, thereby being able to reduce the ohmic contact resistance as much as possible. In a surge condition, the surge current can also be diffused through the wide junction barrier region with a larger size in the first direction A (lateral direction) to adjust the current path. This helps to disperse the electric field intensity, so that the electric field lines can be more evenly distributed in the diode, enabling the surge current under surge conditions to flow uniformly in a wider area rather than concentrating on a single straight path (such as a traditional long-strip P region and N region), reducing the current density in each local area and improving the surge resistance of the diode. In addition, due to the existence of the dumbbell-shaped wide region 302, the contact area of the Schottky region is larger, so that the diode can have a lower on-state voltage drop at a low current density.

[0062] Furthermore, a metal layer can be formed on the first surface. Among them, when the first doping region 30 can be the Schottky region, the part of the metal layer corresponding to the first preset position is Schottky metal, and the part of the metal layer corresponding to the second preset position can be ohmic contact metal; when the second doping region 20 can be the Schottky region, the part of the metal layer corresponding to the second preset position is Schottky metal, and the part of the metal layer corresponding to the first preset position is ohmic contact metal.

[0063] Specifically, the material of the Schottky metal may include, but is not limited to, any one or more of titanium, aluminum, tungsten, molybdenum, titanium carbide, titanium tungsten, nickel chromium alloy, and gold.

[0064] Specifically, the material of the ohmic contact metal may include, but is not limited to, any one or more combinations of nickel (Ni), titanium (Ti), aluminum (Al), silver (Ag), gold (Au), aluminum silicon alloy (AlSi), platinum (Pt), palladium (Pd), tantalum (Ta), and cobalt (Co).

[0065] In some alternative embodiments, in order to further reduce the ohmic contact resistance of the device, the diode structure further includes an ohmic contact region 40, as Figure 4 and Figure 7 shown. In this embodiment, the dumbbell shape includes two wide regions 302 and a narrow region 301 connecting the two wide regions 302; when the doping type of the first doping region 30 is P-type and the doping types of the second doping region 20 and the semiconductor substrate 10 are both N-type, the first doping region 30 further has a third preset region located in a first preset region, and the third preset region is located in the wide region 302. On this basis, the ohmic contact region 40 extends from the third preset region into the first doping region 30, the doping type of the ohmic contact region 40 is the same as that of the first doping region 30, and the doping concentration of the ohmic contact region 40 is greater than that of the first doping region 30. It can be understood that the lateral dimension of the wide region 302 is relatively large, so as to facilitate the formation of a relatively large-area ohmic contact region 40, and further achieve the effect of reducing the ohmic contact resistance by increasing the contact area of the ohmic contact region.

[0066] In some other alternative embodiments, in order to further reduce the ohmic contact resistance of the device, the diode structure further includes an ohmic contact region 40, as Figure 3 and Figure 6 shown. In this embodiment, when the doping type of the second doping region 20 is P-type and the doping types of the first doping region 30 and the semiconductor substrate 10 are both N-type, the ohmic contact region 40 extends from a second preset region into the second doping region 20, the doping type of the ohmic contact region 40 is the same as that of the second doping region 20, and the doping concentration of the ohmic contact region 40 is greater than that of the second doping region 20. It can be understood that the region between the narrow region of one dumbbell shape in the second preset region and the wide region of an adjacent dumbbell shape in the first direction A is a narrow junction barrier region, and the region between the wide regions of two dumbbell shapes respectively adjacent to one dumbbell shape in the first direction in the second preset region is a wide junction barrier region. Since the lateral dimension of the wide junction barrier region is relatively large, it is convenient to form a relatively large-area ohmic contact region 40, and further achieve the effect of reducing the ohmic contact resistance by increasing the contact area of the ohmic contact region.

[0067] ​Figure 1 As shown, the above-mentioned second doping region 20 can extend from the first surface to a depth of 0.3 - 2 μm in the semiconductor substrate. The doping concentration of the first doping region 30 can be 2e15 - 1e21 cm -3 , and the doping concentration of the second doping region 20 is 1e15 - 5e19 cm -3 . As Figure 3 , Figure 4 , Figure 6 and Figure 7 shown, the depth of the above-mentioned ohmic contact region 40 can be 0.1 - 0.8 μm. The doping concentration of the above-mentioned ohmic contact region 40 can be 5e18 - 1e22 cm -3 .

[0068] In some embodiments, as Figure 2 shown, when the doping types of the first doping region 30 and the second doping region 20 are opposite, the doping concentration of any one of the second doping region 20 and the first doping region 30 can be greater than the doping concentration of the semiconductor matrix 10.

[0069] Specifically, when the doping type of the semiconductor matrix 10 can be N-type, the doping type of the first doping region 30 can be P-type. At this time, the first doping region 30 is a P-type doping region, the doping type of the second doping region 20 can be N-type, and the second doping region 20 is an N+ doping region; or, when the doping type of the semiconductor matrix 10 can be N-type, the doping type of the first doping region 30 can be N-type, and the first doping region 30 is an N+ doping region, the doping type of the second doping region 20 can be P-type. At this time, the second doping region 20 is a P-type doping region. It can be understood that the diode structure provided by this embodiment can be a diode structure with an N+ short-circuit region.

[0070] In this embodiment, a metal layer is formed on the first doping region 30 and the second doping region 20 in the structure, and an ohmic contact can be formed between the metal layer and the first doping region 30 and between the metal layer and the second doping region 20. Exemplarily, when the doping concentration of the N-type semiconductor matrix 10 is the above-mentioned doping concentration, the doping concentration of the N-type first doping region 30 or the N-type second doping region 20 in this embodiment can be 1e19 - 1e22 cm -3In the above embodiments, the transverse dimensions of the wider regions at both ends of the dumbbell shape are relatively large. The regions with relatively large transverse dimensions will increase the carrier transport area, which can increase the injection efficiency per unit area, improve the carrier concentration in the drift region, and reduce the resistance. Under surge conditions, the anode region is actually dominated by the parallel connection of two current flow paths. For example, when the first doping region 30 is a P-type doping region and the second doping region 20 is an N+-type doping region, one of the shunt paths is the pn junction path dominated by the dumbbell-shaped P-type doping region (the first doping region 30). The high injection efficiency of the pn junction improves the drift region resistance. At a high current density, the injected carrier concentration increases and becomes the dominant path. The other shunt path is the path of the N+-type doping region (the second doping region 20) in the gap between any two adjacent dumbbell-shaped P-type doping regions, which can directly conduct electrons. Since there is no pn junction, it becomes the dominant path at a low current density. At the same time, since there are no minority carriers participating in this path (the N+-type doping region path), the reverse recovery characteristics will be improved. In addition, a large number of electrons flow through the lower part of the P-type doping region and enter the N+-type doping region. The longer the electron flow path under the P-type region, the greater the probability of the pn junction being turned on. The dumbbell-shaped P-type doping region ensures the area of the heavily doped P-type region and the area of the lightly doped N+-type region through the P-type configuration scheme with a combination of wide and narrow regions, and increases the length of the electron flow path under the P-type region, reducing the current density at which the pn junction is turned on.

[0071] In some alternative embodiments, as Figure 2 shown, when the doping types of the first doping region 30 and the second doping region 20 are the same, the first doping region 30 and the second doping region 20 may have different doping concentrations. Further, the doping concentration of the first doping region 30 may be greater than the doping concentration of the second doping region 20; or, the doping concentration of the first doping region 30 may be less than the doping concentration of the second doping region 20. It can be understood that a diode provided by this embodiment may be a local high-low junction diode structure.

[0072] Specifically, when the doping type of the semiconductor substrate 10 may be N-type, the doping types of both the first doping region 30 and the second doping region 20 may be P-type. Among them, the first doping region 30 corresponding to the first preset region of the dumbbell shape may be a heavily doped P-type region, and the doping concentration may be 5e17~1e20 cm -3 , and the second doping region 20 corresponding to the surrounding region (the second preset region that is not dumbbell-shaped) of the dumbbell shape may be a lightly doped P-type region, and the doping concentration may be 5e15~5e18 cm -3 .

[0073] In the above embodiments, due to the low barrier of the lightly doped P-type region, the lightly doped P-type region can play a dominant role at a small current density. Since the injection efficiency of the lightly doped P-type region is low, the reverse peak current can be reduced and the reverse recovery characteristics can be improved. The heavily doped P-type region is turned on at a large current density (such as a surge current). Since its injection efficiency is high after being turned on, the conduction characteristics can be improved under surge conditions. Moreover, the dumbbell-shaped P-type doped region, through the configuration scheme of width matching (the dumbbell shape has a wide region and a narrow region), ensures the area of the heavily doped P-type region with large injection and the area of the lightly doped region with small injection, coping with the large-current working mode and the small-current working mode of the diode structure, and further enabling the diode structure to have good surge resistance at a large current density and good reverse recovery characteristics at a small current density.

[0074] To improve the problem of peak electric field, in some embodiments, the side line of the first preset region in the first surface can be a curve. That is, the side line of the dumbbell shape can be a curve. Optionally, the radius of curvature of the curve corresponding to the wide region of the dumbbell shape is greater than 0, and the radius of curvature of the curve corresponding to the narrow region of the dumbbell shape can be less than 0.

[0075] In some embodiments, as Figure 1 shown, the above-mentioned first doping region 30 and second doping region 20 can be the active regions of the diode structure. The diode structure can further include a terminal region (not shown in the figure), and the terminal region has a terminal structure. Optionally, the terminal structure is one of a field line loop structure, a JTE structure, a field plate structure, and a hybrid terminal structure.

[0076] In some embodiments, the diode structure can further include a passivation layer, which is located in the terminal region and covers the above-mentioned terminal structure. Exemplarily, the material of the passivation layer can include, but is not limited to, one or a combination of more of silicon oxide (SiO2), silicon nitride (SiN X )), resistive polysilicon (SIPOS), and polyimide (PI).

[0077] In some alternative embodiments, the width of the dumbbell shape in the long axis direction can be 1 to 10 μm, and the width in the short axis direction can be 0.3 to 8 μm. It can be understood that the width of the dumbbell shape in the long axis direction is greater than the width in the short axis direction. In the above embodiments, the configuration of the dumbbell shape can enable the diode structure to cope with the large-current working mode and the small-current working mode through the combination of the large-injection area and the small-injection area. By setting the dimensions of the dumbbell shape in the long axis direction and the short axis direction within the above ranges respectively, the distribution of current in the diode structure can be further improved, forming multiple current paths, which is beneficial to the uniform flow of current in the diode structure.

[0078] As can be seen from the above description, the above embodiments of the present utility model achieve the following technical effects:

[0079] Applying the technical solution of the present utility model, a diode structure is provided. The diode structure includes a semiconductor substrate, a first doping region, and a second doping region. Among them, the semiconductor substrate has a first surface. The first doping region and the second doping region both extend from the first surface into the semiconductor substrate. The first doping region has a plurality of first preset regions located in the first surface. The plurality of first preset regions are spaced apart from each other in pairs. The figure formed by the side lines of the first preset regions in the first surface is dumbbell-shaped; the second doping region has a second preset region located in the first surface, and the second preset region is the region in the first surface other than the first preset region. The first doping region and the second doping region have different doping types or different doping concentrations. The present application has the following beneficial effects: When the figure formed by the side lines of the first preset regions in the first surface is dumbbell-shaped and the second preset region surrounds each first preset region, because the dumbbell shape has a wide shape at both ends and a narrow shape in the middle, the lateral dimension or area of only a part of the first doping region corresponding to the two end regions of the dumbbell shape in the first doping region can be increased, while the lateral dimension or area of a part of the first doping region corresponding to the middle region of the dumbbell shape in the first doping region is reduced. Thus, the lateral dimension or area of a part of the second doping region corresponding to the middle region of the dumbbell shape in the second doping region is also increased. The region with a larger lateral dimension will increase the carrier transmission area, allowing more carriers to pass through simultaneously, reducing the resistance per unit area, providing a lower resistance path, and enabling the electric field lines to naturally tend to flow along the region with a larger lateral dimension, forming multiple parallel low-resistance paths in the diode. Therefore, through the present application, under stable operating conditions (rated current), the diode structure can also have good output current capacity; at the same time, even under surge conditions, the surge current can be diffused through the region with a larger lateral dimension, realizing the adjustment of the current path, which helps to disperse the electric field intensity, enabling the electric field lines to be more evenly distributed in the diode, making the surge current under surge conditions flow uniformly in a wider region, rather than concentrating on a single straight path (such as traditional long strip-shaped P regions and N regions), reducing the current density in each local region, and improving the surge resistance of the diode. In summary, through the present application, the problem of poor surge resistance of diodes in the prior art is solved, and the effect of achieving injection balance between the surge current condition and the rated current condition of the diode structure is achieved.

[0080] The above are only the preferred embodiments of the present utility model and are not used to limit the present utility model. For those skilled in the art, the present utility model can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A diode structure, characterized in that, Comprising: A semiconductor substrate having a first surface; A first doped region extending from the first surface into the semiconductor substrate and having a plurality of first preset regions located in the first surface, the plurality of first preset regions being spaced apart from each other in pairs, and the figure formed by the side lines of the first preset regions in the first surface being dumbbell-shaped; A second doped region extending from the first surface into the semiconductor substrate and having a second preset region located in the first surface, the second preset region being the region in the first surface other than the first preset region; At least one of the first doped region and the second doped region has a doping type different from that of the semiconductor substrate.

2. The diode structure according to claim 1, wherein The dumbbell shape has a major axis and a minor axis perpendicular to each other and includes two wide regions and a narrow region connecting the two wide regions, the two wide regions being symmetric about the extension line of the minor axis of the dumbbell shape, and the connection line of the two wide regions coinciding with the extension line of the major axis of the dumbbell shape; The plurality of first preset regions include a plurality of first sub-preset regions and a plurality of second sub-preset regions alternately distributed in a first direction, the figure formed by the side lines of the first sub-preset regions in the first surface being a first dumbbell shape, and the figure formed by the side lines of the second sub-preset regions in the first surface being a second dumbbell shape; The extension lines of the minor axes of the plurality of first dumbbell shapes coincide in the first direction, the extension lines of the major axes of the plurality of second dumbbell shapes coincide in the first direction, and the extension lines of the minor axes of the plurality of first dumbbell shapes coincide with the extension lines of the major axes of the plurality of second dumbbell shapes in the first direction.

3. The diode structure according to claim 2, wherein The plurality of first preset regions further include a plurality of the first sub-preset regions and a plurality of the second sub-preset regions alternately distributed in a second direction, the extension lines of the major axes of the plurality of first dumbbell shapes coincide in the second direction, the extension lines of the minor axes of the plurality of second dumbbell shapes coincide in the second direction, and the extension lines of the major axes of the plurality of first dumbbell shapes coincide with the extension lines of the minor axes of the plurality of second dumbbell shapes in the second direction.

4. The diode structure according to claim 1, wherein The dumbbell shape has a major axis and a minor axis perpendicular to each other and includes two wide regions and a narrow region connecting the two wide regions, the two wide regions being symmetric about the extension line of the minor axis of the dumbbell shape, and the connection line of the two wide regions coinciding with the extension line of the major axis of the dumbbell shape; The plurality of first preset regions include a plurality of third sub-preset regions and a plurality of fourth sub-preset regions alternately distributed in a first direction, the figure formed by the side lines of the third sub-preset regions in the first surface being a third dumbbell shape, and the figure formed by the side lines of the fourth sub-preset regions in the first surface being a fourth dumbbell shape; The extension lines of the short axes of the plurality of third dumbbell shapes coincide in the first direction, the extension lines of the short axes of the plurality of fourth dumbbell shapes coincide in the first direction, and the connection line in the first direction between the central points of the wide regions of two adjacent fourth dumbbell shapes coincides with the extension lines of the short axes of the plurality of third dumbbell shapes.

5. The diode structure according to claim 4, wherein The plurality of first preset regions further include a plurality of third sub-preset regions and a plurality of fourth sub-preset regions that are alternately distributed in the second direction, the extension lines of the long axes of the plurality of third dumbbell shapes coincide in the second direction, and the extension lines of the long axes of the plurality of fourth dumbbell shapes coincide in the second direction.

6. The diode structure according to any one of claims 1 to 5, wherein The doping types of the first doping region and the second doping region are opposite; or, the doping types of the first doping region and the second doping region are the same.

7. The diode structure according to claim 6, wherein When the doping types of the first doping region and the second doping region are opposite, the doping type of the semiconductor substrate is the same as or different from that of the first doping region.

8. The diode structure according to claim 7, characterized in that, The diode structure further includes: The dumbbell shape includes two wide regions and a narrow region connecting the two wide regions; When the doping type of the first doping region is P-type and the doping types of the second doping region and the semiconductor substrate are both N-type, the first doping region further has a third preset region located in the first preset region, and the third preset region is located in the wide region; An ohmic contact region extends from the third preset region into the first doping region, the ohmic contact region has the same doping type as the first doping region, and the doping concentration of the ohmic contact region is greater than the doping concentration of the first doping region.

9. The diode structure according to claim 7, wherein When the doping type of the second doping region is P-type and the doping types of the first doping region and the semiconductor substrate are both N-type, the diode structure further includes: An ohmic contact region extends from the second preset region into the second doping region, the ohmic contact region has the same doping type as the second doping region, and the doping concentration of the ohmic contact region is greater than the doping concentration of the second doping region.

10. The diode structure according to claim 6, wherein When the doping types of the first doping region and the second doping region are the same, the doping concentrations of the first doping region and the second doping region are different.

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