Fast recovery diode and manufacturing method thereof

Abstract

According to the fast recovery diode and the manufacturing method thereof, the N-type isolation layer, the N-type contact structure and the trench gate structure are introduced, so that a transverse JFET structure is introduced into the anode of the fast recovery diode, the injection efficiency of anode current is improved, the hole injection efficiency of a P-type emitter is regulated and controlled, the distribution of carriers in a device is optimized, and the performance of the device is improved. Under the condition that an extra minority carrier lifetime control technology is not needed, excellent reverse recovery performance is obtained, and the problems of voltage and current abnormal oscillation and electromagnetic interference can be well suppressed. In addition, the problem of large electric leakage caused by a traditional fast recovery diode minority carrier life control mode can be solved, and therefore the operation stability and reliability of the device are improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor manufacturing technology, and in particular to a fast recovery diode and its manufacturing method. Background Technology

[0002] Power devices, acting as a bridge between high-voltage and low-voltage components, are widely used in rail transportation, aerospace, photovoltaics, and new energy fields. They are a crucial foundation for energy conservation and emission reduction, and key components driving social progress. Fast recovery diodes (FRDs), as an important part of power devices, are widely used in rectifier circuits, bootstrap circuits, power integrated circuits, and inverter circuits. To improve the efficiency of power conversion and utilization, it is essential to enhance the performance of fast recovery diodes, such as their forward voltage drop and reverse recovery performance. However, there is a trade-off between forward voltage drop and reverse recovery performance, requiring further improvement to address this trade-off and enhance the overall performance of fast recovery diodes.

[0003] like Figure 1 The diagram shows a schematic of a traditional fast recovery diode, which mainly consists of a metal cathode 100, an N-type substrate 101, an N-type buffer layer 102, an N-type drift layer 103, a P-type body layer 104, a P-type emitter 105, and a metal anode 106 stacked sequentially. To improve this trade-off, traditional fast recovery diodes require additional minority carrier lifetime control techniques, such as diffused platinum, high-energy electron irradiation, and localized hydrogen / helium injection. However, heavy metals like platinum pose pollution problems, and high-energy electron irradiation and localized hydrogen / helium injection require high-capacity equipment, while also incurring high production costs and irradiation issues in the fabrication process. Summary of the Invention

[0004] The purpose of this invention is to provide a fast recovery diode and its manufacturing method, so as to solve the problem that there is a trade-off between the forward voltage drop and reverse recovery performance of the fast recovery diode in the prior art, and that it is difficult to solve.

[0005] To address the aforementioned technical problems, this invention provides a fast recovery diode, comprising: a metal cathode, an N-type substrate, an N-type buffer layer, an N-type drift layer, a P-type body region, a P-type emitter, and a metal anode, stacked sequentially; wherein the fast recovery diode further comprises: an N-type isolation layer, an N-type contact structure, and a trench gate structure, wherein the N-type isolation layer is located between the P-type body region and the P-type emitter, the N-type contact structure is juxtaposed with the P-type emitter and connected to the metal anode, and the trench gate structure is connected to the metal anode and extends into the N-type drift layer.

[0006] Optionally, in the fast recovery diode, the P-type emitter includes a first P-type emitter and a second P-type emitter, the first P-type emitter and the second P-type emitter being disposed on both sides of the trench gate structure and both connected to the trench gate structure.

[0007] Optionally, in the fast recovery diode, the N-type contact structure includes a first N-type contact structure and a second N-type contact structure. The first N-type contact structure and the first P-type emitter are placed side by side, and the first N-type contact structure and the trench gate structure are respectively located on opposite sides of the first P-type emitter. The second N-type contact structure and the second P-type emitter are placed side by side, and the second N-type contact structure and the trench gate structure are respectively located on opposite sides of the second P-type emitter.

[0008] Optionally, in the fast recovery diode, the N-type contact structure includes a first N-type contact structure and a second N-type contact structure, wherein the first N-type contact structure and the second N-type contact structure are respectively disposed on both sides of the trench gate structure and are both connected to the trench gate structure.

[0009] Optionally, in the fast recovery diode, the P-type emitter includes a first P-type emitter and a second P-type emitter, the first P-type emitter and the first N-type contact structure are placed side by side and the first P-type emitter and the trench gate structure are respectively located on opposite sides of the first N-type contact structure, the second P-type emitter and the second N-type contact structure are placed side by side and the second P-type emitter and the trench gate structure are respectively located on opposite sides of the second N-type contact structure.

[0010] Optionally, in the fast recovery diode, the thickness of the N-type isolation layer is between 0.5 μm and 2 μm.

[0011] Optionally, in the fast recovery diode, the doping concentration of the N-type isolation layer is between 1 × 10⁻⁶. 14 cm -3 ~1×10 17 cm -3 between.

[0012] Optionally, in the fast recovery diode, the N-type isolation layer extends from the bottom of the P-type emitter to the P-type emitter side, and the N-type contact structure is located on the N-type isolation layer.

[0013] Optionally, in the fast recovery diode, the doping concentration of the N-type contact structure is between 1 × 10⁻⁶. 14 cm -3 ~1×10 20 cm -3 between.

[0014] The present invention also provides a method for manufacturing a fast recovery diode as described above, the method comprising:

[0015] A semiconductor substrate is provided, and an ion implantation process is performed on the semiconductor substrate to form an N-type substrate, an N-type buffer layer, an N-type drift layer, a P-type body layer, an N-type isolation layer and a P-type emitter stacked sequentially, and an N-type contact structure juxtaposed with the P-type emitter is also formed;

[0016] A trench gate structure is formed in the semiconductor substrate, the trench gate structure extending into the N-type drift layer; and,

[0017] A metal cathode is formed on the surface of the N-type substrate away from the N-type buffer layer, and a metal anode is formed on the surface of the P-type emitter away from the P-type body layer. The trench gate structure, the N-type contact structure, and the P-type emitter are all connected to the metal anode.

[0018] In the fast recovery diode and its manufacturing method provided by this invention, by introducing an N-type isolation layer, an N-type contact structure, and a trench gate structure, a lateral JFET structure is introduced at the anode of the fast recovery diode. This increases the anode current injection efficiency, thereby regulating the hole injection efficiency of the P-type emitter and optimizing the internal carrier distribution of the device. Excellent reverse recovery performance is achieved without the need for additional minority carrier lifetime control technology, and abnormal voltage and current oscillations and electromagnetic interference problems are effectively suppressed. Furthermore, this invention can reduce the excessive leakage current problem caused by traditional minority carrier lifetime control methods in fast recovery diodes, thereby improving the operational stability and reliability of the device. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of a traditional fast recovery diode.

[0020] Figure 2 This is a schematic diagram of the fast recovery diode according to Embodiment 1 of the present invention.

[0021] Figure 3 This is a schematic diagram of the fast recovery diode according to Embodiment 2 of the present invention.

[0022] Figure 4 This is a schematic diagram of the fast recovery diode according to Embodiment 3 of the present invention.

[0023] Figure 5 This is a schematic diagram of the fast recovery diode according to Embodiment 4 of the present invention.

[0024] The reference numerals in the attached figures are explained as follows:

[0025] 100 - Metal cathode; 101 - N-type substrate; 102 - N-type buffer layer; 103 - N-type drift layer; 104 - P-type bulk layer; 105 - P-type emitter; 106 - Metal anode.

[0026] 20 - Fast recovery diode; 200 - Metal cathode; 201 - N-type substrate; 202 - N-type buffer layer; 203 - N-type drift layer; 204 - P-type body layer; 2040 - First P-type body layer; 2041 - Second P-type body layer; 205 - P-type emitter; 2050 - First P-type emitter; 2051 - Second P-type emitter; 206 - Metal anode; 207 - N-type isolation layer; 2070 - First N-type isolation layer; 2071 - Second N-type isolation layer; 208 - N-type contact structure; 2080 - First N-type contact structure; 2081 - Second N-type contact structure; 209 - Trench gate structure.

[0027] 30 - Fast recovery diode; 300 - Metal cathode; 301 - N-type substrate; 302 - N-type buffer layer; 303 - N-type drift layer; 304 - P-type body layer; 3040 - First P-type body layer; 3041 - Second P-type body layer; 305 - P-type emitter; 3050 - First P-type emitter; 3051 - Second P-type emitter; 306 - Metal anode; 307 - N-type isolation layer; 3070 - First N-type isolation layer; 3071 - Second N-type isolation layer; 308 - N-type contact structure; 3080 - First N-type contact structure; 3081 - Second N-type contact structure; 309 - Trench gate structure.

[0028] 40 - Fast recovery diode; 400 - Metal cathode; 401 - N-type substrate; 402 - N-type buffer layer; 403 - N-type drift layer; 404 - P-type body layer; 4040 - First P-type body layer; 4041 - Second P-type body layer; 405 - P-type emitter; 4050 - First P-type emitter; 4051 - Second P-type emitter; 406 - Metal anode; 407 - N-type isolation layer; 4070 - First N-type isolation layer; 4071 - Second N-type isolation layer; 408 - N-type contact structure; 4080 - First N-type contact structure; 4081 - Second N-type contact structure; 409 - Trench gate structure.

[0029] 50 - Fast recovery diode; 500 - Metal cathode; 501 - N-type substrate; 502 - N-type buffer layer; 503 - N-type drift layer; 504 - P-type body layer; 5040 - First P-type body layer; 5041 - Second P-type body layer; 505 - P-type emitter; 5050 - First P-type emitter; 5051 - Second P-type emitter; 506 - Metal anode; 507 - N-type isolation layer; 5070 - First N-type isolation layer; 5071 - Second N-type isolation layer; 508 - N-type contact structure; 5080 - First N-type contact structure; 5081 - Second N-type contact structure; 509 - Trench gate structure. Detailed Implementation

[0030] The fast recovery diode and its manufacturing method proposed in this invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of this invention will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of this invention.

[0031] The terminology used in this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. Unless otherwise defined in this application, the technical or scientific terms used in this invention should be understood in their ordinary sense by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, "a" or "one," and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. "A plurality" or "several" indicates two or more. Unless otherwise indicated, terms such as "upper / upper layer," "lower / lower layer," and similar terms are for ease of description only and are not limited to a location or spatial orientation. Terms such as "comprising" or "including" mean that the element or object preceding "comprising" covers the element or object listed following "comprising" or "including" and its equivalents, and does not exclude other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections and can include electrical connections, whether direct or indirect. The singular forms “a,” “the,” and “the” used in this specification and appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0032] The core idea of ​​this invention is to provide a fast recovery diode and its manufacturing method. By introducing an N-type isolation layer, an N-type contact structure, and a trench gate structure, a lateral JFET structure is introduced into the anode of the fast recovery diode, increasing the anode current injection efficiency and thereby regulating the hole injection efficiency of the P-type emitter. This optimizes the internal carrier distribution of the device, achieving excellent reverse recovery performance without the need for additional minority carrier lifetime control technology. Furthermore, it effectively suppresses abnormal voltage and current oscillations and electromagnetic interference. In addition, this invention reduces the excessive leakage current caused by traditional minority carrier lifetime control methods in fast recovery diodes, thereby improving the operational stability and reliability of the device.

[0033] Next, the fast recovery diode and its manufacturing method proposed in this invention will be further described through four specific structures.

[0034] Example 1

[0035] Please refer to Figure 2 This is a schematic diagram of the fast recovery diode according to Embodiment 1 of the present invention. Figure 2 As shown, the fast recovery diode 20 includes: a metal cathode 200, an N-type substrate 201, an N-type buffer layer 202, an N-type drift layer 203, a P-type body region layer 204, a P-type emitter 205, and a metal anode 206 stacked sequentially; wherein, the fast recovery diode 20 further includes: an N-type isolation layer 207, an N-type contact structure 208, and a trench gate structure 209, wherein the N-type isolation layer 207 is located between the P-type body region layer 204 and the P-type emitter 205, the N-type contact structure 208 and the P-type emitter 205 are placed side by side and connected to the metal anode 206, and the trench gate structure 209 is connected to the metal anode 206 and extends into the N-type drift layer 203.

[0036] Here, by introducing the N-type isolation layer 207, the N-type contact structure 208, and the trench gate structure 209, a lateral JFET structure is introduced into the anode of the fast recovery diode 20, increasing the anode current injection efficiency and thereby regulating the hole injection efficiency of the P-type emitter 205. This optimizes the internal carrier distribution of the device, achieving excellent reverse recovery performance without requiring additional minority carrier lifetime control technology. It also effectively suppresses abnormal voltage and current oscillations and electromagnetic interference. Furthermore, it reduces the excessive leakage current caused by traditional fast recovery diode minority carrier lifetime control methods, thereby improving the device's operational stability and reliability.

[0037] The thickness of the N-type isolation layer 207 is between 0.5 μm and 2 μm, that is, the cross-sectional width of the N-type isolation layer 207 along the stacking direction of each layer is between 0.5 μm and 2 μm.

[0038] In this embodiment, the doping concentration of the N-type isolation layer 207 is between 1×10⁻⁶. 14 cm -3 ~1×10 17 cm -3 Between. Here, the doping concentration of the N-type contact structure 208 is also between 1 × 10. 14 cm -3 ~1×10 17 cm -3 The doping concentration of the N-type contact structure 208 can be the same as that of the N-type isolation layer 207. The N-type contact structure 208 forms a Schottky contact. In other embodiments of this application, the doping concentration of the N-type contact structure 208 can be higher or lower than that of the N-type isolation layer 207.

[0039] Please continue to refer to this. Figure 2 In this embodiment, the trench gate structure 209 extends from the lower surface of the metal anode 206 into the N-type drift layer 203. The P-type body layer 204, the N-type isolation layer 207, and the P-type emitter 205 respectively include: a first P-type body layer 2040, a first N-type isolation layer 2070, and a first P-type emitter 2050 located on one side of the trench gate structure 209, and a second P-type body layer 2041, a second N-type isolation layer 2071, and a second P-type emitter 2051 located on the other side of the trench gate structure 209.

[0040] Here, the first P-type body layer 2040 and the second P-type body layer 2041 are located on both sides of the trench gate structure 209 and are both connected to the trench gate structure 209; the first N-type isolation layer 2070 and the second N-type isolation layer 2071 are located on both sides of the trench gate structure 209 and are both connected to the trench gate structure 209; the first P-type emitter 2050 and the second P-type emitter 2051 are located on both sides of the trench gate structure 209 and are both connected to the trench gate structure 209.

[0041] In this embodiment, the N-type isolation layer 207 extends from the bottom of the P-type emitter 205 to the side of the P-type emitter 205, and the N-type contact structure 208 is located on the N-type isolation layer 207. Specifically, the N-type contact structure 208 includes a first N-type contact structure 2080 and a second N-type contact structure 2081. The first N-type contact structure 2080 is located on the first N-type isolation layer 2070, and the second N-type contact structure 2081 is located on the second N-type isolation layer 2071. The first N-type contact structure 2080 and the trench gate structure 209 are located on opposite sides of the first P-type emitter 2050, and the second N-type contact structure 2081 and the trench gate structure 209 are located on opposite sides of the second P-type emitter 2051.

[0042] In this embodiment, the bottom surface of the N-type contact structure 208 is higher than the bottom surface of the P-type emitter 205, meaning the thickness of the P-type emitter 205 is greater than the thickness of the N-type contact structure 208. In other embodiments of this application, the bottom surface of the N-type contact structure 208 may also be lower than the bottom surface of the P-type emitter 205; for example, the bottom surface of the N-type contact structure 208 may be connected to the surface of the P-type body layer 204.

[0043] Accordingly, this application also provides a method for manufacturing the above-mentioned fast recovery diode 20, combined with... Figure 2 As shown, the manufacturing method of the fast recovery diode includes:

[0044] A semiconductor substrate is provided, and an ion implantation process is performed on the semiconductor substrate to form an N-type substrate 201, an N-type buffer layer 202, an N-type drift layer 203, a P-type body layer 204, an N-type isolation layer 207 and a P-type emitter 205 stacked sequentially, and an N-type contact structure 208 is also formed juxtaposed with the P-type emitter 205.

[0045] A trench gate structure 209 is formed in the semiconductor substrate, the trench gate structure 209 extending into the N-type drift layer 203; and...

[0046] A metal cathode 200 is formed on the surface of the N-type substrate 201 opposite to the N-type buffer layer 202, and a metal anode 206 is formed on the surface of the P-type emitter 205 opposite to the P-type body layer 204. The trench gate structure 209, the N-type contact structure 208, and the P-type emitter 205 are all connected to the metal anode 206.

[0047] The N-type substrate 201, N-type buffer layer 202, N-type drift layer 203, P-type body layer 204, N-type isolation layer 207, P-type emitter 205, and N-type contact structure 208 can be formed by performing an ion implantation process on the semiconductor substrate. This application embodiment does not limit the formation order or ion implantation concentration. For example, after forming the P-type emitter 205, a first patterned mask layer can be formed on the surface of the semiconductor substrate. Then, an ion implantation process (which may further include an annealing process) can be performed on the semiconductor substrate exposed by the first patterned mask layer to form the N-type contact structure 208. Alternatively, after forming the N-type contact structure 208, a second patterned mask layer can be formed on the surface of the semiconductor substrate. Then, an ion implantation process (which may further include an annealing process) can be performed on the semiconductor substrate exposed by the second patterned mask layer to form the P-type emitter 205.

[0048] Furthermore, the trench gate structure 209 can be formed by etching the semiconductor substrate to create trenches, and depositing a dielectric layer and a conductive layer in the trenches. The cross-sectional width of the trenches can, for example, be between 0.5 μm and 2 μm. In this embodiment, the trench gate structure 209 can also be formed before the P-type emitter 205, the N-type contact structure 208, the N-type isolation layer 207, the P-type body layer 204, and other structures. For example, after forming the P-type body layer 204, a third patterned mask layer can be formed on the surface of the semiconductor substrate. Then, an etching process can be performed on the semiconductor substrate exposed by the third patterned mask layer to form a trench, and a dielectric layer and a conductive layer can be deposited in the trench to form the trench gate structure 209. Alternatively, after forming the trench gate structure 209, a fourth patterned mask layer can be formed on the surface of the semiconductor substrate. Then, an ion implantation process (which may further include an annealing process) can be performed on the semiconductor substrate exposed by the fourth patterned mask layer to form the P-type body layer 204.

[0049] In this embodiment, the N-type substrate 201 is formed by a heavily N-type doping process, the N-type buffer layer 202 is formed by a light N-type doping process, the N-type drift layer 203 is formed by a light N-type doping process, the P-type bulk layer 204 is formed by a P-type doping process, the P-type emitter 205 is formed by a heavily P-type doping process, and the N-type isolation layer 207 and the N-type contact structure 208 are formed by an N-type doping process. The N-type isolation layer 207 and the N-type contact structure 208 can be formed simultaneously or separately. The specific doping concentration can be adjusted according to actual needs.

[0050] Furthermore, the metal cathode 200 and the metal anode 206 can be made of single metals such as aluminum, copper, platinum, and gold, or alloys of multiple metals.

[0051] In the fast recovery diode manufacturing method provided in this application embodiment, by introducing an N-type isolation layer 207, an N-type contact structure 208, and a trench gate structure 209, a lateral JFET structure is introduced at the anode of the fast recovery diode, increasing the anode current injection efficiency and thereby regulating the hole injection efficiency of the P-type emitter 208. This optimizes the internal carrier distribution of the device, achieving excellent reverse recovery performance without requiring additional minority carrier lifetime control technology, and effectively suppressing abnormal voltage and current oscillations and electromagnetic interference. Furthermore, this invention can reduce the excessive leakage current problem caused by traditional fast recovery diode minority carrier lifetime control methods, thereby improving the operational stability and reliability of the device.

[0052]

Example 2

[0053] Please refer to Figure 3 This is a schematic diagram of the fast recovery diode according to Embodiment 2 of the present invention. Figure 3 As shown, the fast recovery diode 30 includes: a metal cathode 300, an N-type substrate 301, an N-type buffer layer 302, an N-type drift layer 303, a P-type body region layer 304, a P-type emitter 305, and a metal anode 306 stacked sequentially; wherein, the fast recovery diode 30 further includes: an N-type isolation layer 307, an N-type contact structure 308, and a trench gate structure 309, wherein the N-type isolation layer 307 is located between the P-type body region layer 304 and the P-type emitter 305, the N-type contact structure 308 is juxtaposed with the P-type emitter 305 and connected to the metal anode 306, and the trench gate structure 309 is connected to the metal anode 306 and extends into the N-type drift layer 303.

[0054] like Figure 3 As shown, and can be combined accordingly. Figure 2 The main difference between this second embodiment and the first embodiment is that, in this second embodiment, the N-type contact structure 308 is formed by an N-type heavy doping process, and its doping concentration is between 1×10⁻⁶. 17 cm -3 ~1×10 20 cm -3 Between. The N-type contact structure 308 forms an ohmic contact.

[0055] In Embodiment 2 of this application, similarly, the first P-type body layer 3040 and the second P-type body layer 3041 are located on both sides of the trench gate structure 309 and are both connected to the trench gate structure 309; the first N-type isolation layer 3070 and the second N-type isolation layer 3071 are located on both sides of the trench gate structure 309 and are both connected to the trench gate structure 309; the first P-type emitter 3050 and the second P-type emitter 3051 are located on both sides of the trench gate structure 309 and are both connected to the trench gate structure 309. The first N-type contact structure 3080 is located on the first N-type isolation layer 3070, and the second N-type contact structure 3081 is located on the second N-type isolation layer 3071. The first N-type contact structure 3080 and the trench gate structure 309 are located on opposite sides of the first P-type emitter 3050, and the second N-type contact structure 3081 and the trench gate structure 309 are located on opposite sides of the second P-type emitter 3051.

[0056] For the parts not described in detail in this embodiment two, please refer to the corresponding embodiment one. This embodiment two will not be described in detail again.

[0057]

Example 3

[0058] Please refer to Figure 4 This is a schematic diagram of the fast recovery diode according to Embodiment 3 of the present invention. Figure 4 As shown, the fast recovery diode 40 includes: a metal cathode 400, an N-type substrate 401, an N-type buffer layer 402, an N-type drift layer 403, a P-type body region layer 404, a P-type emitter 405, and a metal anode 406 stacked sequentially; wherein, the fast recovery diode 40 further includes: an N-type isolation layer 407, an N-type contact structure 408, and a trench gate structure 409, wherein the N-type isolation layer 407 is located between the P-type body region layer 404 and the P-type emitter 405, the N-type contact structure 408 is juxtaposed with the P-type emitter 405 and connected to the metal anode 406, and the trench gate structure 409 is connected to the metal anode 406 and extends into the N-type drift layer 403.

[0059] like Figure 4 As shown, and can be combined accordingly. Figure 3The main difference between Embodiment 3 and Embodiment 2 is that, in Embodiment 3, the first N-type contact structure 4080 and the second N-type contact structure 4081 are respectively disposed on both sides of the trench gate structure 409 and are both connected to the trench gate structure 409. That is, in Embodiment 3, the first P-type emitter 4050 and the first N-type contact structure 4080 are placed side-by-side, with the first P-type emitter 4050 and the trench gate structure 409 located on opposite sides of the first N-type contact structure 4080, and the second P-type emitter 4051 and the second N-type contact structure 4081 are placed side-by-side, with the second P-type emitter 4051 and the trench gate structure 409 located on opposite sides of the second N-type contact structure 4081.

[0060] In this third embodiment, similarly, the first P-type body layer 4040 and the second P-type body layer 4041 are located on both sides of the trench gate structure 409 and are both connected to the trench gate structure 409; the first N-type isolation layer 4070 and the second N-type isolation layer 4071 are located on both sides of the trench gate structure 409 and are both connected to the trench gate structure 409. The first N-type contact structure 4080 is located on the first N-type isolation layer 4070, and the second N-type contact structure 4081 is located on the second N-type isolation layer 4071. The N-type contact structure 408 is formed by an N-type heavy doping process, and its doping concentration is between 1×10⁻⁶. 17 cm -3 ~1×10 20 cm -3 Between. The N-type contact structure 408 forms an ohmic contact.

[0061] For the parts not detailed in this embodiment three, please refer to the corresponding embodiments one and two. This embodiment three will not be repeated here.

[0062]

Example 4

[0063] Please refer to Figure 5 This is a schematic diagram of the fast recovery diode according to Embodiment 4 of the present invention. Figure 5 As shown, the fast recovery diode 50 comprises, in sequence, a metal cathode 500, an N-type substrate 501, an N-type buffer layer 502, an N-type drift layer 503, a P-type body region layer 504, a P-type emitter 505, and a metal anode 506; wherein, the fast recovery diode 50 further comprises: an N-type isolation layer 507, an N-type contact structure 508, and a trench gate structure 509, wherein the N-type isolation layer 507 is located between the P-type body region layer 504 and the P-type emitter 505, the N-type contact structure 508 is juxtaposed with the P-type emitter 505 and connected to the metal anode 506, and the trench gate structure 509 is connected to the metal anode 506 and extends into the N-type drift layer 503.

[0064] like Figure 5 As shown, and can be combined accordingly. Figure 4 The main difference between this fourth embodiment and the third embodiment is that, in this fourth embodiment, the N-type contact structure 508 is formed by an N-type doping process, and its doping concentration is between 1×10⁻⁶. 14 cm -3 ~1×10 17 cm -3 Between; the N-type contact structure 508 and the N-type isolation layer 507 can have the same doping concentration, and the two can be formed by simultaneous doping process or stepwise doping.

[0065] In this fourth embodiment, similarly, the first N-type contact structure 5080 and the second N-type contact structure 5081 are respectively disposed on both sides of the trench gate structure 509 and are both connected to the trench gate structure 509. The first P-type emitter 5050 and the trench gate structure 509 are respectively located on opposite sides of the first N-type contact structure 5080, and the second P-type emitter 5051 and the trench gate structure 509 are respectively located on opposite sides of the second N-type contact structure 5081. The first P-type body layer 5040 and the second P-type body layer 5041 are respectively located on both sides of the trench gate structure 509 and are both connected to the trench gate structure 509; the first N-type isolation layer 5070 and the second N-type isolation layer 5071 are respectively located on both sides of the trench gate structure 509 and are both connected to the trench gate structure 509. The first N-type contact structure 5080 is located on the first N-type isolation layer 5070, and the second N-type contact structure 5081 is located on the second N-type isolation layer 5071.

[0066] For the parts not detailed in this embodiment four, please refer to embodiments one to three respectively. This embodiment four will not be repeated here.

[0067] In this application, references to "one embodiment" or "some embodiments" mean that a feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment or at least some embodiments of this application. Therefore, the appearance of the phrases "in one embodiment" or "in some embodiments" throughout this application does not necessarily refer to the same or the same embodiments. Furthermore, in one or more embodiments, features, structures, or characteristics can be combined in any suitable combination and / or sub-combination.

[0068] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and not for limiting the scope of this application. The embodiments of this application can be combined in any way without departing from the spirit and scope of this application. Those skilled in the art should also understand that various modifications can be made to the embodiments without departing from the scope and spirit of this application. The scope of this application is defined by the appended claims.

Claims

1. A fast recovery diode, characterized in that, The fast recovery diode comprises: a metal cathode, an N-type substrate, an N-type buffer layer, an N-type drift layer, a P-type body region, a P-type emitter, and a metal anode stacked sequentially; wherein, the fast recovery diode further comprises: an N-type isolation layer, an N-type contact structure, and a trench gate structure, wherein the N-type isolation layer is located between the P-type body region and the P-type emitter, the N-type contact structure is juxtaposed with the P-type emitter and connected to the metal anode, and the trench gate structure is connected to the metal anode and extends into the N-type drift layer.

2. The fast recovery diode as described in claim 1, characterized in that, The P-type emitter includes a first P-type emitter and a second P-type emitter, which are respectively disposed on both sides of the trench gate structure and are both connected to the trench gate structure.

3. The fast recovery diode as described in claim 2, characterized in that, The N-type contact structure includes a first N-type contact structure and a second N-type contact structure. The first N-type contact structure and the first P-type emitter are placed side by side, and the first N-type contact structure and the trench gate structure are respectively located on opposite sides of the first P-type emitter. The second N-type contact structure and the second P-type emitter are placed side by side, and the second N-type contact structure and the trench gate structure are respectively located on opposite sides of the second P-type emitter.

4. The fast recovery diode as described in claim 1, characterized in that, The N-type contact structure includes a first N-type contact structure and a second N-type contact structure, which are respectively disposed on both sides of the trench grid structure and are both connected to the trench grid structure.

5. The fast recovery diode as described in claim 4, characterized in that, The P-type emitter includes a first P-type emitter and a second P-type emitter. The first P-type emitter and the first N-type contact structure are placed side by side, and the first P-type emitter and the trench gate structure are respectively located on opposite sides of the first N-type contact structure. The second P-type emitter and the second N-type contact structure are placed side by side, and the second P-type emitter and the trench gate structure are respectively located on opposite sides of the second N-type contact structure.

6. The fast recovery diode as described in any one of claims 1 to 5, characterized in that, The thickness of the N-type isolation layer is between 0.5 μm and 2 μm.

7. The fast recovery diode as described in any one of claims 1 to 5, characterized in that, The doping concentration of the N-type isolation layer is between 1×10⁻⁶. 14 cm -3 ~1×10 17 cm -3 between.

8. The fast recovery diode as described in any one of claims 1 to 5, characterized in that, The N-type isolation layer extends from the bottom of the P-type emitter to the side of the P-type emitter, and the N-type contact structure is located on the N-type isolation layer.

9. The fast recovery diode as described in any one of claims 1 to 5, characterized in that, The doping concentration of the N-type contact structure is between 1×10⁻⁶. 14 cm -3 ~1×10 20 cm -3 between.

10. A method for manufacturing a fast recovery diode as described in any one of claims 1 to 9, characterized in that, The method for manufacturing the fast recovery diode includes: A semiconductor substrate is provided, and an ion implantation process is performed on the semiconductor substrate to form an N-type substrate, an N-type buffer layer, an N-type drift layer, a P-type body layer, an N-type isolation layer and a P-type emitter stacked sequentially, and an N-type contact structure juxtaposed with the P-type emitter is also formed; A trench gate structure is formed in the semiconductor substrate, the trench gate structure extending into the N-type drift layer; and, A metal cathode is formed on the surface of the N-type substrate away from the N-type buffer layer, and a metal anode is formed on the surface of the P-type emitter away from the P-type body layer. The trench gate structure, the N-type contact structure, and the P-type emitter are all connected to the metal anode.

Images