Hybrid PIN Schottky diode

Abstract

The invention provides a hybrid PIN Schottky diode, and the diode comprises an epitaxial layer which is provided with a first surface; the doped regions are located in the epitaxial layer and distributed in an array mode in the first direction and the second direction, each doped region comprises a first doped part and a second doped part protruding out of part of the first doped part in the second direction, and the first direction and the second direction are parallel to the first surface and are different; and the metal silicide is positioned on the first surface and covers at least part of the second doping part and part of the first doping part. According to the hybrid PIN Schottky diode, the problem of low surge capacity of the hybrid PIN Schottky diode in the prior art is solved.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, and more specifically, to a hybrid PIN Schottky diode. Background Technology

[0002] Compared to traditional PiN diodes, Schottky diodes exhibit lower forward voltage drop and, as unipolar devices, higher switching frequencies, shorter reverse recovery times, and lower turn-on losses. Silicon carbide (SiC), a wide bandgap material (3C-SiC: 2.3 eV, 6H-SiC: 2.9 eV, 4H-SiC: 3.2 eV), has a critical breakdown electric field 8–10 times higher than silicon. Silicon carbide (SiC) Schottky diodes, as important power electronic devices, have attracted considerable attention due to their superior performance in high-power and high-frequency applications. Therefore, compared to traditional silicon-based PiN diodes, SiC Schottky diodes exhibit lower forward voltage drop and faster switching speeds, primarily attributed to the wide bandgap characteristics of SiC and the unipolar operating principle of the Schottky diode.

[0003] Currently, to further improve the performance of Schottky diodes, especially in high voltage and high surge current applications, two structures are commonly used: Junction Barrier Schottky (JBS) and Hybrid PIN Schottky (MPS) structures. The JBS structure forms a PN junction by injecting heavily P-type doping around the Schottky contact region. It utilizes the electric field shielding effect of the depletion layer to reduce the electric field strength of the Schottky junction, thereby reducing reverse leakage current and improving breakdown voltage. However, JBS diodes have limited ability to withstand high surge currents because their P-type injection region is relatively small, making it difficult to effectively distribute current under high current conditions. The MPS structure further improves upon the JBS structure by adding metal to the P-type injection region to form an ohmic contact. When the current exceeds a certain threshold, the PN junction turns on, allowing current to flow through the ohmic contact, thus improving the device's surge current capability. However, while improving surge capability, the traditional MPS structure, due to the increased P-type injection region, leads to an increased forward voltage drop (VF) and higher power consumption, a problem particularly prominent in high-power applications.

[0004] The information disclosed above in the background section is only intended to enhance the understanding of the background art of the art described herein. Therefore, the background art may contain certain information that does not constitute prior art known to those skilled in the art in this country. Summary of the Invention

[0005] The main objective of this application is to provide a hybrid PIN Schottky diode to at least solve the problem of low surge capability in existing hybrid PIN Schottky diodes.

[0006] To achieve the above objectives, according to one aspect of this application, a hybrid PIN Schottky diode is provided, comprising: an epitaxial layer having a first surface; a plurality of doped regions located in the epitaxial layer and arrayed along a first direction and a second direction, each doped region including a first doped portion and a second doped portion protruding from a portion of the first doped portion in the second direction, the first direction and the second direction being parallel to the first surface and different from each other; and a metal silicide located on the first surface and covering at least a portion of the second doped portion and a portion of the first doped portion.

[0007] In some embodiments, the second doped portion has a first protrusion and a second protrusion that are contacted at both ends of the first doped portion in a second direction, and the first protrusion and the second protrusion are symmetrically arranged about the axis of symmetry of the first doped portion.

[0008] In some embodiments, the multiple doped regions are arranged in multiple rows along a first direction, and the multiple doped regions in any two adjacent rows are staggered.

[0009] In some embodiments, the spacing between any two adjacent rows of doped regions is equal.

[0010] In some embodiments, the spacing between any two adjacent doped regions in the same row of doped regions is equal.

[0011] In some embodiments, any two doped regions are identical in size and shape.

[0012] In some embodiments, the doped region has a projection on the first surface, wherein the shape of the projection region corresponding to the first doped portion is rectangular, and the shape of the projection region corresponding to the second doped portion is arc-shaped.

[0013] In some embodiments, the end face of the doped region in the first direction is an arc surface.

[0014] In some embodiments, the first surface has a groove in which a metal silicide is located.

[0015] In some embodiments, the hybrid PIN Schottky diode further includes: a Schottky metal, a covering metal silicide, and a first surface other than the metal silicide covering.

[0016] According to the technical solution of this application, a hybrid PIN Schottky diode includes an epitaxial layer, a plurality of doped regions arrayed in the epitaxial layer along a first direction and a second direction, and a metal silicide located on the epitaxial layer and covering a portion of the doped regions. The first and second directions are both parallel to a first surface of the epitaxial layer and are different from each other. Each doped region includes a first doped portion and a second doped portion, with the second doped portion protruding from a portion of the first doped portion in the second direction. The metal silicide is located on the first surface and covers at least a portion of the second doped portion and a portion of the first doped portion. The beneficial effect of this application is that, because the second doped portion protrudes from a portion of the first doped portion in the second direction, the presence of the second doped portion increases the width of the portion of the first doped portion in the second direction. Therefore, for the doped region, different positions in the first direction have different widths in the second direction. This means that the doped region integrates a large-size implanted region (the portion of the doped region with a larger width in the second direction, including a portion of the first doped portion and a second doped portion protruding from that portion of the first doped portion) while also integrating a small-size implanted region (the portion of the doped region with a smaller width in the second direction, i.e., another portion of the first doped portion). Furthermore, since the metal silicide covers at least a portion of the second doped region and a portion of the first doped region, it can be considered that the metal silicide covers at least a portion of the large-size implantation region of the doped region. The large-size implantation region and the metal silicide covering it can provide a low-impedance path for the hybrid PIN Schottky diode through an ohmic contact. This path can effectively distribute current to the circuit under high current conditions, enabling the device to have stronger current carrying capacity and withstand higher surge current in forward conduction mode, thereby reducing the forward conduction voltage drop (VF) of the device and thus reducing power consumption. In addition, the presence of the large-size implantation region does not weaken the electric field shielding effect of the small-size implantation region. On the contrary, since the large-size and small-size implantation regions are closely adjacent, they can work together to help form a more uniform depletion layer under high reverse bias voltage, providing more effective electric field shielding. This effectively reduces reverse leakage current and improves the device's withstand voltage. In summary, this application solves the problem of low surge capability of hybrid PIN Schottky diodes in the prior art, while ensuring that the device has a low forward voltage drop. It achieves a significant increase in forward current density and surge current capability while maintaining high withstand voltage and low reverse leakage current, thus optimizing the overall device performance. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0018] Figure 1A schematic diagram of the device surface cell distribution of a hybrid PIN Schottky diode according to an embodiment of this application is shown;

[0019] Figure 2 It shows Figure 1 The diagram shows the positional relationship between the first doped portion and the second doped portion in a hybrid PIN Schottky diode.

[0020] Figure 3 It shows Figure 1 The diagram shows the positional relationship between the large-size injection region and the small-size injection region in a hybrid PIN Schottky diode.

[0021] Figure 4 Show Figure 1 The diagram shows a cross-sectional structure of a hybrid PIN Schottky diode along the C1-C1 direction.

[0022] Figure 5 It shows Figure 1 The diagram shows a cross-sectional structure of a hybrid PIN Schottky diode along the C2-C2 direction.

[0023] Figure 6 It shows Figure 1 The diagram shows a cross-sectional structure of a hybrid PIN Schottky diode along the C3-C3 direction.

[0024] The above figures include the following reference numerals:

[0025] 10. Epitaxial layer; 20. Doped region; 201. First doped region; 202. Second doped region; 203. Large-size implanted region; 204. Small-size implanted region; 30. Metal silicide; 40. Schottky metal; 50. Substrate; 60. Backside metal. Detailed Implementation

[0026] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0027] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0028] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of the invention described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0029] It should be understood that when an element (such as a layer, film, region, or substrate) is described as being "on" another element, the element may be directly on the other element, or there may be an intermediate element present. Furthermore, in the specification and claims, when an element is described as being "connected" to another element, the element may be "directly connected" to the other element, or "connected" to the other element via a third element.

[0030] As described in the background section, existing JBS structures form a PN junction by injecting heavily P-type doping around the Schottky contact region. The electric field strength of the Schottky junction is reduced by utilizing the electric field shielding effect of the depletion layer, thereby reducing reverse leakage current and improving breakdown voltage. However, JBS diodes have limited ability to withstand high surge currents because their P-type injection region is small, making it difficult to effectively distribute current under high current conditions. MPS structures further improve upon JBS structures by adding metal to the P-type injection region to form an ohmic contact (metal silicide). When the current exceeds a certain threshold, the PN junction turns on, allowing current to flow through the ohmic contact, thus improving the device's surge current capability. However, while improving surge capability, the traditional MPS structure also increases forward voltage drop (VF) and energy consumption due to the increased P-type injection region. To address the problem of high forward voltage drop in existing diodes, embodiments of this application provide a hybrid PIN Schottky diode.

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0032] Figure 1 This is a schematic diagram of the device surface cell distribution of a hybrid PIN Schottky diode according to an embodiment of this application. Figure 2 It shows Figure 1 The diagram shows the positional relationship between the first doped portion and the second doped portion in a hybrid PIN Schottky diode. Figure 3 It shows Figure 1This diagram illustrates the positional relationship between the large-size injection region and the small-size injection region in a hybrid PIN Schottky diode. (Combined with...) Figure 1 Figure 2 and Figure 3 As shown, the hybrid PIN Schottky diode includes:

[0033] Epitaxial layer 10 has a first surface;

[0034] Multiple doped regions 20 are located in the epitaxial layer 10 and are arrayed along the first direction A and the second direction B. Each doped region 20 includes a first doped portion 201 and a second doped portion 202 that protrudes from the first doped portion 201 in the second direction B. The first direction A and the second direction B are parallel to the first surface and are different from each other.

[0035] Metal silicide 30 is located on the first surface and covers at least a portion of the second doped portion 202 and a portion of the first doped portion 201.

[0036] In this embodiment, since the second doped portion 202 protrudes from a portion of the first doped portion 201 (which extends along the first direction A) in the second direction B, the presence of the second doped portion 202 increases the width of the first doped portion 201 in the second direction B. Therefore, for the doped region 20, different positions in the first direction A have different widths in the second direction B. This means that the doped region 20 integrates both a large-size implantation region 203 (the portion of the doped region 20 with a larger width (S2) in the second direction B, including: a portion of the first doped portion 201 located in the central region of the doped region 20 in the first direction A and a second doped portion 202 protruding from this portion of the first doped portion 201) and a small-size implantation region 204 (the portion of the doped region 20 with a smaller width (S1) in the second direction B, i.e., another portion of the first doped portion 201 located at both ends of the doped region 20 in the first direction A). Furthermore, since the metal silicide 30 covers at least a portion of the second doped region 202 and a portion of the first doped region 201, it can be considered that the metal silicide 30 covers at least a portion of the large-size implantation region 203 of the doped region 20. The large-size implantation region 203 and the metal silicide 30 covering the large-size implantation region 203 can provide a low-impedance path for the hybrid PIN Schottky diode through an ohmic contact. This path can effectively distribute current to the circuit under high current conditions, enabling the device to have stronger current carrying capacity and withstand higher surge current in forward conduction, thereby reducing the forward conduction voltage drop (VF) of the device and thus reducing power consumption. In addition, the presence of the large-size implantation region 203 does not weaken the electric field shielding effect of the small-size implantation region 204. On the contrary, since the large-size implantation region 203 and the small-size implantation region 204 are closely adjacent, they can cooperate to help form a more uniform depletion region (e.g., under high reverse bias voltage). Figure 1 (As shown in the dashed box in the image), it provides more effective electric field shielding, which effectively reduces reverse leakage current and improves the device's withstand voltage capability. In summary, this application solves the problem of low surge capability of hybrid PIN Schottky diodes in the prior art, while ensuring that the device has a low forward voltage drop. It achieves a significant increase in forward current density and surge current capability while maintaining high withstand voltage and low reverse leakage current, thus optimizing the overall device performance.

[0037] It should be noted that the core of the hybrid PIN Schottky diode lies in the formation of a PIN structure and a Schottky contact on the epitaxial layer through doping. The doped region and epitaxial layer described above form part of the PIN structure of the hybrid PIN Schottky diode in this application. A Schottky contact is a non-rectifying contact between a metal and a semiconductor, formed on the surface of the semiconductor. The hybrid PIN Schottky diode in this application also includes a Schottky metal in contact with the epitaxial layer; the interface between the Schottky metal and the epitaxial layer can form a Schottky contact.

[0038] Figure 4 Show Figure 1 The diagram shows a cross-sectional structure of a hybrid PIN Schottky diode along the C1-C1 direction. Figure 5 It shows Figure 1 The diagram shows a cross-sectional structure of a hybrid PIN Schottky diode along the C2-C2 direction. Figure 6 It shows Figure 1 The diagram shows a cross-sectional structure of a hybrid PIN Schottky diode along the C3-C3 direction. Figures 4 to 6 As shown, in some alternative embodiments, the Schottky metal 40 of the hybrid PIN Schottky diode of this application is located on the first surface and covers the metal silicide 30 and the first surface excluding the metal silicide 30 covering.

[0039] It is understandable that, since the multiple doped regions 20 of the hybrid PIN Schottky diode of this application are arrayed in the epitaxial layer 10, such as Figure 1 As shown, when the Schottky metal 40 is located on the aforementioned first surface and covers the metal silicide 30 and the first surface excluding the metal silicide 30, the Schottky metal 40 can form a Schottky contact with the epitaxial layer 10 located between any two adjacent doped regions 20 on the first surface. Furthermore, when the device is in a reverse bias state, since the doped region 20 of this application integrates a large-size implantation region 203 (the wider portion of the doped region 20 in the second direction B, including: a portion of the first doped portion 201 located in the central region of the doped region 20 in the first direction A and a second doped portion 202 protruding from this portion of the first doped portion 201) and a small-size implantation region 204 (the narrower portion of the doped region 20 in the second direction B, i.e., another portion of the first doped portion 201 located at both ends of the doped region 20 in the first direction A), the depletion region range formed by the small-size implantation region 204 in the first direction A and the second direction B is different from the depletion region range formed by the large-size implantation region 203 in the first direction A and the second direction B (see reference). Figure 1Thus, the depletion region formed by the doped region 20 of this application can be extended in the first direction A and the second direction B to obtain a wider depletion region. A wider depletion region means more effective electric field shielding. Thus, the electric field of the corresponding region of the Schottky contact can be shielded more effectively through the above-described embodiments, so that the electric field strength of the corresponding region of the Schottky contact can be significantly reduced, thereby reducing the reverse leakage current and improving the withstand voltage capability of the device.

[0040] refer to Figures 1 to 6 It should be noted that the epitaxial layer 10 and the doped region 20 in the hybrid PIN Schottky diode of this application have opposite doping types. The first doped portion 201 and the second doped portion 202 are actually interconnected. In order to facilitate the description of the beneficial effects of the design of the doped region 20, this application artificially divides the doped region 20 into the first doped portion 201 and the second doped portion 202. Therefore, the doping type, implantation dose of dopant ions, and implantation energy of the first doped portion 201 and the second doped portion 202 are the same. When there is no external voltage, the Schottky contact forms a potential energy barrier, i.e., a Schottky barrier, at the interface between the Schottky metal 40 and the first surface of the epitaxial layer 10. When the hybrid PIN Schottky diode is forward biased (i.e., a positive voltage is applied to the Schottky contact side), the Schottky barrier decreases, allowing current to flow. At this time, the device exhibits the characteristics of a Schottky diode, and the current is formed by the diffusion of majority carriers flowing from the Schottky metal 40 to the epitaxial layer 10 through the metal-semiconductor contact.

[0041] In addition, such as Figures 4 to 6 As shown, the hybrid PIN Schottky diode further includes a substrate 50 and a back metal 60. The substrate 50 is located on the second surface of the epitaxial layer 10, and the second surface is disposed opposite to the first surface in the thickness direction of the epitaxial layer 10. The back metal 60 is located on the side of the substrate 50 facing away from the epitaxial layer 10. It should be noted that the substrate 50 and the epitaxial layer 10 have the same doping type, but the doping type is opposite to that of the doped region 20.

[0042] It is understandable that, such as Figure 1 As shown, each doped region 20 in the above-mentioned hybrid PIN Schottky diode together with the surrounding epitaxial layer 10 constitutes a cell.

[0043] In some alternative implementations, combined with Figure 1 and Figure 2 As shown, in order to ensure the uniformity of cell current and voltage in the hybrid PIN Schottky diode, the second doped portion 202 has a first protrusion (not shown) and a second protrusion (not shown) that are in contact with the two ends of the first doped portion 201 in the second direction B. The first protrusion and the second protrusion are symmetrically arranged about the axis of symmetry of the first doped portion 201.

[0044] In the above embodiments, the axis of symmetry of the first doped portion 201 can be aligned with the first direction A. Therefore, when the second doped portion 202 has a first protrusion and a second protrusion that are contacted at both ends of the first doped portion 201 in the second direction B, the first and second protrusions can be symmetrically arranged about the axis of symmetry of the first doped portion 201. Alternatively, the axis of symmetry of the first doped portion 201 can also be aligned with the second direction B. In this case, the first and second protrusions themselves can be symmetrically arranged about the axis of symmetry of the first doped portion 201. Based on this, when the device is reverse biased, the PN junction formed by the doped region 20 (including the first doped portion 201, the first and second protrusions) and the epitaxial layer 10 can extend the depletion region range in the second direction B (e.g., ...). Figure 1 As shown in the circular depletion region, this ensures that the electric field strength in the corresponding area of ​​the Schottky contact is not excessively high. Furthermore, the symmetrically arranged first and second protrusions help to form a symmetrical electric field distribution within the device, which greatly reduces electric field inhomogeneity and avoids electric field concentration at the Schottky contact edge, thereby improving the device's withstand voltage and reliability. When the device is in forward conduction, the symmetrically arranged first and second protrusions ensure that the circuit path from the Schottky metal 40 to the metal silicide 30 is symmetrical on the device's horizontal plane (first surface). This helps to form a more uniform current conduction mode, ensuring that regardless of the direction of current flow, the symmetrical doped region 20 can ensure that the current is uniformly distributed along a predetermined path, avoiding current concentration in a small area, thereby improving the device's reliability.

[0045] In some alternative implementations, such as Figure 1 As shown, the multiple doped regions 20 are arranged in multiple rows along the first direction A, and the multiple doped regions 20 in any two adjacent rows of doped regions 20 are staggered.

[0046] In the above embodiments, the staggered arrangement of the doped regions 20 can occupy the first surface region of the epitaxial layer 10 more densely, thereby increasing the number and coverage of the doped regions 20 within the effective space. Compared to traditional elongated doped regions, the staggered arrangement of the multiple doped regions 20 in this application also allows more of the epitaxial layer 10 to be exposed to the Schottky metal 40, thereby increasing the effective area of ​​the Schottky contact and further reducing the forward voltage drop (VF). Furthermore, under reverse bias, the staggered arrangement of the multiple doped regions 20 can more effectively expand the depletion region, ensuring that each Schottky contact is surrounded by doped regions 20 for electric field shielding, which helps reduce reverse leakage current and further improves the device's withstand voltage capability. In addition, under forward bias, each row of doped regions 20 works together with adjacent rows of doped regions 20 to form a staggered current path network, allowing current to flow in multiple directions. This effectively improves the problem of excessive current concentration on a single path, thereby further reducing the forward voltage drop (VF) and power consumption.

[0047] It is understood that each row in the above embodiments includes multiple doped regions 20 spaced apart, and any two adjacent rows of doped regions 20 are adjacent in the second direction B.

[0048] Furthermore, such as Figure 1 As shown, in some optional embodiments, the spacing between any two adjacent rows of doped regions 20 is equal.

[0049] In the above embodiments, when the spacing between two adjacent rows of doped regions 20 in the second direction B is equal, the electric field shielding effect formed between each row of doped regions 20 and the adjacent row of doped regions 20 will be more balanced. This means that, under reverse bias, the electric field intensity distribution around the corresponding region of the Schottky contact will be more uniform, which helps to improve the breakdown voltage of the device and further enhance the stability and reliability of the device under high reverse voltage. Furthermore, equal spacing allows the current to be evenly distributed through multiple paths during forward conduction, avoiding current concentration on a few paths, which could lead to local overheating or overload, thereby further reducing the voltage drop during forward conduction and reducing power consumption. In addition, equal spacing helps maintain the stability and symmetry of the device structure, ensuring consistent device performance under different operating conditions.

[0050] Similarly, as Figure 1 As shown, in some alternative embodiments, in order to improve the uniformity of the electric field distribution around the Schottky contact region when the device is reverse biased, and to reduce current concentration effects when the device is forward biased, the spacing between any two adjacent doped regions 20 in the same row of doped regions 20 is equal. In the first direction A, the spacing between any two adjacent doped regions 20 is equal.

[0051] In some alternative implementations, such as Figures 1 to 3 As shown, any two doped regions 20 are identical in size and shape. This helps to form a uniform depletion layer, ensuring consistent device performance. Furthermore, maintaining the same size and shape for all doped regions 20 simplifies the fabrication process, reduces production costs, and improves production efficiency.

[0052] In some alternative implementations, combined with Figure 1 and Figure 2 As shown, the doped region 20 has a projection on the first surface. The shape of the projection region corresponding to the first doped part 201 is rectangular, and the shape of the projection region corresponding to the second doped part 202 is arc-shaped.

[0053] It should be noted that the aforementioned bow shape has a chord and a corresponding arc, wherein the chord of the bow shape coincides with a portion of a long side of the rectangle, and the arc of the bow shape protrudes beyond the rectangle. In the above embodiment, the first doped portion 201 corresponding to the rectangle provides basic electric field shielding, and the second doped portion 202 corresponding to the bow shape enhances the shielding effect of a portion of the edge of the first doped portion 201, thereby effectively shielding the electric field in the region corresponding to the Schottky contact, reducing the electric field strength at the Schottky contact interface, reducing reverse leakage current, and improving the breakdown voltage performance of the device. Furthermore, corresponding to the aforementioned bow shape, the side of the second doped portion 202 protruding from the first doped portion 201 can be an arc surface, thus improving the problem of electric field concentration on the side of the second doped portion 202 protruding from the first doped portion 201.

[0054] For example, when the second doped portion 202 has a first protrusion and a second protrusion that are contacted at both ends of the first doped portion 201 in the second direction B, and the first and second protrusions are symmetrically arranged about the axis of symmetry of the first doped portion 201, the shape of the projection area of ​​the doped region 20 corresponding to the first doped portion 201 in the projection on the first surface can be rectangular, the shape of the projection area of ​​the doped region 20 corresponding to the first protrusion in the projection on the first surface can be arc-shaped, denoted as the first arc shape, and the shape of the projection area of ​​the doped region 20 corresponding to the second protrusion in the projection on the first surface can be arc-shaped, denoted as the second arc shape. The first and second arc shapes are symmetrical about the axis of symmetry of the rectangle, such as... Figure 2 As shown. Further, after connecting the arcs of the first and second arcs with an arc line, the arcs of the first and second arcs, along with the portion of the rectangle located between the first and second arcs in the second direction B, can be divided into a circle. The remaining portion of the rectangle, excluding the portion located between the first and second arcs in the second direction B, is located on opposite sides of the circle in the first direction, as shown. Figure 3As shown. Furthermore, the center of the circle can coincide with the geometric center of the rectangle. Thus, as... Figure 1 As shown, the metal silicide 30 can cover the above-mentioned circular area. When the device has a large current, the PN junction between the doped region 20 and the epitaxial layer 10 corresponding to the circular area is turned on as a path to allow current to flow, thereby improving the current carrying capacity and surge capacity of the device. The area in the epitaxial layer 10 other than the doped region 20 is the Schottky region.

[0055] It is understandable that, such as Figure 3 As shown, the aforementioned circle can correspond to the large-size injection region 203, and the other part of the rectangle located on opposite sides of the circle in the first direction A can correspond to the small-size injection region 204. Of course, in other embodiments, the shape of the projection area of ​​the large-size injection region 203 on the first surface can also be one of ellipse, triangle, square, and other polygons.

[0056] Furthermore, in order to avoid electric field concentration, in some other embodiments, the connection interface between the first doped portion and the second doped portion in the epitaxial layer can be an arc surface.

[0057] In other alternative implementations, such as Figures 1 to 3 As shown, when the projected shape of the first doped portion 201 is rectangular, its edges are relatively sharp, which can lead to electric field concentration. To improve the electric field concentration problem at the end of the first doped portion 201, the end face of the doped region 20 in the first direction A is curved. In this way, electric field concentration caused by sharp edges is avoided, and the reliability of the device is improved.

[0058] In some alternative implementations, such as Figures 4 to 6 As shown, the first surface has grooves (not labeled in the figure), and the metal silicide 30 is located in the grooves. In this way, on the one hand, it can ensure that the final device... Figure 3 The large-size injection region 203 shown retains metal silicide 30 to enhance the device's forward conduction capability and surge capability. On the other hand, by placing the metal silicide 30 in the groove, the ohmic contact area can be increased, which helps to reduce contact resistance, reduce energy loss when current passes through the contact area, and optimize the device's conduction performance.

[0059] In this invention, such as Figures 4 to 6As shown, the substrate 50 can be N-type, the epitaxial layer 10 can be N-type, and the doped region 20 can be P-type. The P-type doped region can be obtained by ion implantation of a dopant, thus the doped region 20 can be an implantation region. Alternatively, in this invention, the substrate 50 can be P-type, the epitaxial layer 10 can be P-type, and the doped region 20 can be N-type. The N-type doped region can be obtained by ion implantation of a dopant. Furthermore, the substrate 50 can be a silicon carbide substrate, and the epitaxial layer 10 can be a silicon carbide epitaxial layer.

[0060] Combination Figures 1 to 3 As shown, when designing the hybrid PIN Schottky diode in any of the above embodiments, the size S3 of the metal silicide 30 (ohmic contact) in the second direction B can be smaller than the size S2 of the large-size injection region 203 in the second direction B. Considering process deviations and current conduction, the distance from the boundary of the metal silicide 30 (ohmic contact) to the boundary of the large-size injection region 203 is greater than the overlay deviation in the process, thereby ensuring that the metal silicide 30 can be completely enclosed by the injection region and preventing the metal silicide from contacting the Schottky junction and affecting leakage current.

[0061] Furthermore, an excessively small size of the metal silicide 30 (ohmic contact) can affect its high-current conduction capability; the specific size needs to be determined in conjunction with the overall cell size and performance. During the design process, the device should first be able to withstand the designed reverse voltage, and then the turn-on forward voltage drop (VF) and surge capability should be considered. Given a fixed implantation dose energy, assuming the implantation width of the elongated first doped portion 201 is S1, in order to shield the Schottky junction between the two cells, the following formula for the depletion region width of a PN junction is used: W = [2ε(V...] bi +V R ) / qN] 1 / 2 (where V) bi For the built-in potential, V R Given the directional voltage, q as the electron charge, N as the injection dose, and ε as the dielectric constant of the semiconductor material, the maximum longitudinal spacing S5 between the first doped portions 201 of two adjacent cells in the second direction B and the maximum lateral spacing S6 between the first doped portions 201 of two adjacent cells in the first direction A can be calculated. The minimum size S2 of the large-size injection region 203 can be calculated by working backward from the minimum value of S4, i.e., the minimum spacing between two circular injections. The values ​​of each parameter in the cell should not be less than the limit value that just completely shields the Schottky junction between the cells, such as... Figure 1 The depletion region in the device is used to ensure a low overall leakage current level.

[0062] Based on this, by modifying the values ​​of S1 and the dimension S7 of the first doped portion 201 in the first direction A to ensure a sufficiently large Schottky area ratio, the dimension S2 of the large-size injection region 203 should be as large as possible to make the ohmic contact area sufficiently large. This ensures both a small forward voltage drop (VF) when the device is turned on and a higher current density, improving current flow and surge capability. This is because the current in the PN junction is mainly formed by the diffusion of majority carriers, and its expression follows the Shockley diode equation: I = I S (e^{qV / (kT)}-1), where I S I is the reverse saturation current, V is the applied forward voltage, q is the electron charge, K is the Boltzmann constant, and T is the temperature; with other parameters remaining constant, I S The forward current is positively correlated with the cross-sectional area of ​​the PN junction. Therefore, increasing the junction area will linearly increase the forward current, thereby enhancing the current carrying capacity and surge capability of the device, and making the PN junction easier to conduct.

[0063] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0064] According to the technical solution of this application, a hybrid PIN Schottky diode includes an epitaxial layer, a plurality of doped regions arrayed in the epitaxial layer along a first direction and a second direction, and a metal silicide located on the epitaxial layer and covering a portion of the doped regions. The first and second directions are both parallel to a first surface of the epitaxial layer and are different from each other. Each doped region includes a first doped portion and a second doped portion, with the second doped portion protruding from a portion of the first doped portion in the second direction. The metal silicide is located on the first surface and covers at least a portion of the second doped portion and a portion of the first doped portion. This application has the following beneficial effects: because the second doped portion protrudes from a portion of the first doped portion in the second direction, the presence of the second doped portion increases the width of the portion of the first doped portion in the second direction. Therefore, for the doped region, different positions in the first direction have different widths in the second direction. This means that the doped region integrates a large-size implanted region (the portion of the doped region with a larger width in the second direction, including a portion of the first doped portion and a second doped portion protruding from that portion of the first doped portion) while also integrating a small-size implanted region (the portion of the doped region with a smaller width in the second direction, i.e., another portion of the first doped portion). Furthermore, since the metal silicide covers at least a portion of the second doped region and a portion of the first doped region, it can be considered that the metal silicide covers at least a portion of the large-size implantation region of the doped region. The large-size implantation region and the metal silicide covering it provide a low-impedance path for the hybrid PIN Schottky diode through an ohmic contact. This path can effectively distribute current to the circuit under high current conditions, reducing the current density of the Schottky contact. This significantly reduces the resistance of current flowing through the Schottky contact during forward conduction, enabling the device to have stronger current carrying capacity and withstand higher surge currents in forward conduction, thereby reducing the forward voltage drop (VF) of the device and thus reducing power consumption. In addition, the presence of the large-size implantation region does not weaken the electric field shielding effect of the small-size implantation region. On the contrary, since the large-size and small-size implantation regions are closely adjacent, they can work together to help form a more uniform depletion layer under high reverse bias voltage, providing more effective electric field shielding. This effectively reduces reverse leakage current and improves the device's withstand voltage. In summary, this application solves the problem of low surge capability of hybrid PIN Schottky diodes in the prior art, while ensuring that the device has a low forward voltage drop. It achieves a significant increase in forward current density and surge current capability while maintaining high withstand voltage and low reverse leakage current, thus optimizing the overall device performance.

[0065] The technical features of the above 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.

[0066] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A hybrid PIN Schottky diode, characterized in that, include: Epitaxial layer, having a first surface; A plurality of doped regions are located in the epitaxial layer and are arrayed along a first direction and a second direction. Each doped region includes a first doped portion and a second doped portion that protrudes from a portion of the first doped portion in the second direction. The first direction and the second direction are parallel to the first surface and are different from each other. A metal silicide is located on the first surface and covers at least a portion of the second doped portion and a portion of the first doped portion.

2. The hybrid PIN Schottky diode according to claim 1, characterized in that, The second doped portion has a first protrusion and a second protrusion that are contacted at both ends of the first doped portion in the second direction, and the first protrusion and the second protrusion are symmetrically arranged about the axis of symmetry of the first doped portion.

3. The hybrid PIN Schottky diode according to claim 2, characterized in that, The multiple doped regions are arranged in multiple rows along the first direction, and the multiple doped regions in any two adjacent rows are staggered.

4. The hybrid PIN Schottky diode according to claim 3, characterized in that, The spacing between any two adjacent rows of doped regions is equal.

5. The hybrid PIN Schottky diode according to claim 3, characterized in that, The spacing between any two adjacent doped regions in the same row is equal.

6. The hybrid PIN Schottky diode according to any one of claims 1 to 5, characterized in that, Any two of the doped regions are identical in size and shape.

7. The hybrid PIN Schottky diode according to any one of claims 1 to 5, characterized in that, The doped region has a projection on the first surface, and the shape of the projection area corresponding to the first doped part is rectangular, while the shape of the projection area corresponding to the second doped part is arc-shaped.

8. The hybrid PIN Schottky diode according to any one of claims 1 to 5, characterized in that, The end face of the doped region in the first direction is an arc surface.

9. The hybrid PIN Schottky diode according to any one of claims 1 to 5, characterized in that, The first surface has a groove, and the metal silicide is located in the groove.

10. The hybrid PIN Schottky diode according to claim 1, characterized in that, The hybrid PIN Schottky diode also includes: Schottky metal covers the metal silicide and the first surface excluding the metal silicide coverage.

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