Fast recovery diode and manufacturing method therefor

Abstract

Provided in the present invention are a fast recovery diode and a manufacturing method therefor. By introducing an N-type isolation layer, an N-type contact structure and a trench gate structure, a lateral JFET structure is introduced into an anode of the fast recovery diode to increase the injection efficiency of an anode current, thereby regulating and controlling the hole injection efficiency of a P-type emitter, thus optimizing the internal carrier distribution of a device, enabling excellent reverse recovery performance without the need for additional minority carrier lifetime control techniques, and also effectively suppressing the problems in respect of abnormal voltage and current oscillations and electromagnetic interference. In addition, the present invention can also mitigate the problem of relatively high leakage current caused by traditional minority carrier lifetime control methods for fast recovery diodes, thereby improving the operation stability and reliability of the device.

Description

Fast recovery diode and manufacturing method thereof TECHNICAL FIELD

[0001] The present application relates to the technical field of semiconductor manufacturing, in particular to a fast recovery diode and a manufacturing method thereof. BACKGROUND

[0002] Power devices are widely used in rail transit, aerospace, photovoltaic and new energy fields as a bridge between strong and weak electrical devices, and are important for energy saving and emission reduction, and are also key components for social progress. Fast recovery diode (FRD) is an important part of power devices, and is widely used in rectifier circuits, bootstrap circuits, power integrated circuits and inverter circuits. In order to improve the conversion and use efficiency of electric energy, it is necessary to improve the performance of fast recovery diode, such as the on-state voltage drop and reverse recovery performance of the device, however, there is a trade-off between the on-state voltage drop and the reverse recovery performance, and it is necessary to further improve the trade-off between the on-state voltage drop and the reverse recovery performance to improve the performance of the fast recovery diode.

[0003] As shown in FIG. 1, it is a structural schematic diagram of a traditional fast recovery diode, which mainly includes 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 region layer 104, a P-type emitter 105 and a metal anode 106 stacked in sequence. In order to improve this trade-off, the traditional fast recovery diode needs to introduce additional minority carrier lifetime control technology, such as diffusion platinum, high-energy electron irradiation and local hydrogen / helium injection, etc. The heavy metals such as platinum have pollution problems, and the high-energy electron irradiation and local hydrogen / helium injection have high requirements for equipment capacity, and the production cost is high, and the preparation process has irradiation problems.

[0004] SUMMARY

[0005] The purpose of the present application is to provide a fast recovery diode and a manufacturing method thereof to solve the trade-off between the on-state voltage drop and the reverse recovery performance of the fast recovery diode in the prior art and the difficult problem.

[0006] In order to solve the above technical problems, the present application provides a fast recovery diode, which comprises: a metal cathode, an N-type substrate, an N-type buffer layer, an N-type drift layer, a P-type body region layer, a P-type emitter and a metal anode stacked in sequence; wherein the fast recovery diode further comprises: an N-type isolation layer, an N-type contact structure and a trench gate structure, the N-type isolation layer is located between the P-type body region layer and the P-type emitter, the N-type contact structure and the P-type emitter are juxtaposed and connected with the metal anode, and the trench gate structure is connected with the metal anode and extends into the N-type drift layer.

[0007] 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 are located on two sides of the trench gate structure and are connected with the trench gate structure.

[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, the first N-type contact structure and the first P-type emitter are located on two sides of the trench gate structure respectively, and the second N-type contact structure and the second P-type emitter are located on two sides of the trench gate structure respectively.

[0009] 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 second N-type contact structure are located on two sides of the trench gate structure and are connected with the trench gate structure.

[0010] 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 located on two sides of the trench gate structure respectively, and the second P-type emitter and the second N-type contact structure are located on two sides of the trench gate structure respectively.

[0011] Optionally, in the fast recovery diode, the thickness of the N-type isolation layer is between 0.5 μm and 2 μm.

[0012] Optionally, in the fast recovery diode, the doping concentration of the N-type isolation layer is between 1×10 14 cm -3 and 1×10 17 cm -3 .

[0013] Optionally, in the fast recovery diode, 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.

[0014] Optionally, in the fast recovery diode, the doping concentration of the N-type contact structure is between 1×10 14 cm -3 and 1×10 20 cm -3 .

[0015] The application further provides a manufacturing method of the fast recovery diode.

[0016] 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 region layer, an N-type isolation layer and a P-type emitter which are stacked in sequence, and an N-type contact structure is formed in parallel with the P-type emitter;

[0017] A trench gate structure is formed in the semiconductor substrate, and the trench gate structure extends into the N-type drift layer; and

[0018] A metal cathode is formed on a surface of the N-type substrate away from the N-type buffer layer, and a metal anode is formed on a surface of the P-type emitter away from the P-type body region layer, and the trench gate structure, the N-type contact structure and the P-type emitter are all connected to the metal anode.

[0019] In the fast recovery diode and the manufacturing method thereof provided by the application, the N-type isolation layer, the N-type contact structure and the trench gate structure are introduced, so that a lateral JFET structure is introduced in the anode of the fast recovery diode, the injection efficiency of the anode current is increased, the hole injection efficiency of the P-type emitter is regulated, the internal carrier distribution of the device is optimized, excellent reverse recovery performance is obtained without additional minority carrier lifetime control technology, and the problems of abnormal voltage and current oscillation and electromagnetic interference are well inhibited. In addition, the application can also reduce the problem of large leakage current caused by the traditional fast recovery diode minority carrier lifetime control mode, thereby improving the operation stability and reliability of the device. BRIEF DESCRIPTION OF DRAWINGS

[0020] FIG. 1 is a structural schematic diagram of a traditional fast recovery diode.

[0021] FIG. 2 is a structural schematic diagram of a fast recovery diode according to an embodiment of the application.

[0022] FIG. 3 is a structural schematic diagram of a fast recovery diode according to another embodiment of the application.

[0023] FIG. 4 is a structural schematic diagram of a fast recovery diode according to another embodiment of the application.

[0024] FIG. 5 is a structural schematic diagram of a fast recovery diode according to another embodiment of the application.

[0025] In the drawings, the reference signs are explained as follows:

[0026] 100 - metal cathode; 101 - N-type substrate; 102 - N-type buffer layer; 103 - N-type drift layer; 104 - P-type body region layer; 105 - P-type emitter; 106 - metal anode.

[0027] 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 region layer; 2040 - first P-type body region layer; 2041 - second P-type body region 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.

[0028] 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 region layer; 3040 - first P-type body region layer; 3041 - second P-type body region 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.

[0029] 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 region layer; 4040 - first P-type body region layer; 4041 - second P-type body region 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.

[0030] 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 region layer; 5040 - first P-type body region layer; 5041 - second P-type body region 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 DESCRIPTION

[0031] The fast recovery diode and the manufacturing method thereof according to the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. The advantages and features of the present application will be more apparent from the following description. It should be noted that the accompanying drawings are very simplified and all use non-precise proportions, only for the purpose of conveniently and clearly assisting the description of the embodiments of the present application.

[0032] The terminology used by the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The articles "a", "an", and "the" as used herein are to be construed to mean "at least one" or "one or more". Unless otherwise noted, the terms "first", "second", and the like, as used herein do not have any specific meaning, but are used only to distinguish one component from another. Also, the terms "one" or "the" do not mean "one and only one", but rather "one or more". The terms "plurality" or "a plurality" mean two or more. Unless otherwise indicated, the terms "upper", "lower", and the like, as used herein do not mean a specific position or spatial orientation, but rather are used to indicate a relative position or spatial orientation. The terms "comprises", "comprising", "includes", "including", and the like, as used herein, mean including, but not limited to. The term "connected" or "coupled" as used herein, means the sharing of a signal, power, or data between components, whether direct or indirect, and whether mechanical, electrical, or electronic. The terms "a" and "an" as used herein mean "one or more" unless otherwise indicated. The term "another" as used herein means "one or more". The term "and / or" as used herein means "and" or "or". The terms "first", "second", and the like, as used herein do not necessarily indicate any order, quantity, or importance, but are used to distinguish one element from another.

[0033] The core idea of the present application is to provide a fast recovery diode and a manufacturing method thereof, by introducing an N-type isolation layer, an N-type contact structure and a trench gate structure, thereby introducing a lateral JFET structure in the anode of the fast recovery diode, increasing the injection efficiency of anode current, thereby regulating the hole injection efficiency of the P-type emitter, and further optimizing the internal carrier distribution of the device, obtaining excellent reverse recovery performance without additional minority carrier lifetime control technology, and also being able to well suppress abnormal voltage and current oscillation and electromagnetic interference problems. In addition, the present application can also reduce the problem of large leakage current caused by the minority carrier lifetime control mode of the traditional fast recovery diode, thereby improving the operation stability and reliability of the device.

[0034] Next, the fast recovery diode and the manufacturing method thereof proposed by the present application will be further described by four specific structures.

[0035] Example 1

[0036] Please refer to FIG. 2, which is a structural schematic diagram of the fast recovery diode of the embodiment one of the present application. As shown in FIG. 2, the fast recovery diode 20 comprises: 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 which are stacked in sequence; wherein the fast recovery diode 20 further comprises: an N-type isolation layer 207, an N-type contact structure 208 and a trench gate structure 209, 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 juxtaposed and connected with the metal anode 206, and the trench gate structure 209 is connected with the metal anode 206 and extends into the N-type drift layer 203.

[0037] 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 in the anode of the fast recovery diode 20, the injection efficiency of anode current is increased, thereby regulating the hole injection efficiency of the P-type emitter 205, and further optimizing the internal carrier distribution of the device, obtaining excellent reverse recovery performance without additional minority carrier lifetime control technology, and also being able to well suppress abnormal voltage and current oscillation and electromagnetic interference problems. In addition, the problem of large leakage current caused by the minority carrier lifetime control mode of the traditional fast recovery diode can also be reduced, thereby improving the operation stability and reliability of the device.

[0038] Among them, 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.

[0039] In the embodiment of the present application, the doping concentration of the N-type isolation layer 207 is between 1x10 14 cm -3 and 1x10 17 cm -3 . Here, the doping concentration of the N-type contact structure 208 is also between 1x10 14 cm -3 and 1x10 17 cm -3 , which can be the same as the doping concentration of the N-type isolation layer 207. The N-type contact structure 208 forms a Schottky contact. In other embodiments of the present application, the doping concentration of the N-type contact structure 208 can be higher than the doping concentration of the N-type isolation layer 207, or can be lower than the doping concentration of the N-type isolation layer 207.

[0040] Please continue to refer to FIG. 2. In the embodiment of the present application, 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 region layer 204, the N-type isolation layer 207, and the P-type emitter 205 correspondingly include: a first P-type body region 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 region 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.

[0041] Here, the first P-type body region layer 2040 and the second P-type body region layer 2041 are respectively located on both sides of the trench gate structure 209 and are connected to the trench gate structure 209; the first N-type isolation layer 2070 and the second N-type isolation layer 2071 are respectively located on both sides of the trench gate structure 209 and are connected to the trench gate structure 209; the first P-type emitter 2050 and the second P-type emitter 2051 are respectively located on both sides of the trench gate structure 209 and are connected to the trench gate structure 209.

[0042] In the embodiment of the present application, 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. Wherein, the first N-type contact structure 2080 and the trench gate structure 209 are respectively located on the opposite sides of the first P-type emitter 2050, and the second N-type contact structure 2081 and the trench gate structure 209 are respectively located on the opposite sides of the second P-type emitter 2051.

[0043] In the embodiment of the present application, the bottom surface of the N-type contact structure 208 is higher than the bottom surface of the P-type emitter 205, that is, the thickness of the P-type emitter 205 is thicker than the thickness of the N-type contact structure 208. In other embodiments of the present application, the bottom surface of the N-type contact structure 208 can 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 can be connected with the surface of the P-type body region layer 204.

[0044] Correspondingly, the embodiment of the present application also provides a manufacturing method of the above-mentioned fast recovery diode 20, which is combined with Fig. 2. The manufacturing method of the fast recovery diode includes:

[0045] providing a semiconductor substrate, and performing ion implantation process 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 region layer 204, an N-type isolation layer 207 and a P-type emitter 205 which are stacked in sequence, and an N-type contact structure 208 which is juxtaposed with the P-type emitter 205;

[0046] forming a trench gate structure 209 in the semiconductor substrate, the trench gate structure 209 extends into the N-type drift layer 203; and,

[0047] forming a metal cathode 200 on the surface of the N-type substrate 201 away from the N-type buffer layer 202, and forming a metal anode 206 on the surface of the P-type emitter 205 away from the P-type body region layer 204, the trench gate structure 209, the N-type contact structure 208 and the P-type emitter 205 are all connected with the metal anode 206.

[0048] The N-type substrate 201, the N-type buffer layer 202, the N-type drift layer 203, the P-type body region layer 204, the N-type isolation layer 207, the P-type emitter 205 and the N-type contact structure 208 can be formed by performing ion implantation process on the semiconductor substrate, and the forming sequence and ion implantation concentration are not limited in the present application. For example, after forming the P-type emitter 205, a first patterned mask layer can be formed on the surface of the semiconductor substrate, and then ion implantation process (which can further include annealing process) is performed on the semiconductor substrate exposed by the first patterned mask layer to form the N-type contact structure 208; or, after forming the N-type contact structure 208, a second patterned mask layer can be formed on the surface of the semiconductor substrate, and then ion implantation process (which can further include annealing process) is performed on the semiconductor substrate exposed by the second patterned mask layer to form the P-type emitter 205.

[0049] Further, the trench gate structure 209 can be formed by etching the semiconductor substrate to form a trench, and then depositing dielectric layer and conductive layer in the trench. The cross-sectional width of the trench can be, for example, between 0.5 μm and 2 μm. In the present application, 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 region layer 204, etc. For example, after forming the P-type body region layer 204, a third patterned mask layer can be formed on the surface of the semiconductor substrate, and then etching process is performed on the semiconductor substrate exposed by the third patterned mask layer to form a trench, and then dielectric layer and conductive layer are deposited in the trench to form the trench gate structure 209; or, after forming the trench gate structure 209, a fourth patterned mask layer can be formed on the surface of the semiconductor substrate, and then ion implantation process (which can further include annealing process) is performed on the semiconductor substrate exposed by the fourth patterned mask layer to form the P-type body region layer 204.

[0050] In the present application, the N-type substrate 201 is formed by N-type heavy doping process, the N-type buffer layer 202 is formed by N-type light doping process, the N-type drift layer 203 is formed by N-type light doping process, the P-type body region layer 204 is formed by P-type doping process, the P-type emitter 205 is formed by P-type heavy doping process, the N-type isolation layer 207 and the N-type contact structure 208 are formed by N-type doping process, and 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.

[0051] Further, the material of the metal cathode 200 and the metal anode 206 can be aluminum, copper, platinum, gold or other metal elements or alloys of multiple metals.

[0052] In the manufacturing method of the fast recovery diode provided by the embodiment of the application, the N-type isolation layer 207, the N-type contact structure 208 and the trench gate structure 209 are introduced, so that a lateral JFET structure is introduced in the anode of the fast recovery diode, the injection efficiency of the anode current is increased, the hole injection efficiency of the P-type emitter 205 is regulated, the internal carrier distribution of the device is optimized, excellent reverse recovery performance is obtained without additional minority carrier lifetime control technology, and the problems of abnormal voltage and current oscillation and electromagnetic interference can be well inhibited. In addition, the application can also reduce the problem of large leakage current caused by the traditional fast recovery diode minority carrier lifetime control mode, thereby improving the operation stability and reliability of the device.

[0053]

Embodiment Two

[0054] Please refer to FIG. 3, which is a structural schematic diagram of the fast recovery diode according to the second embodiment of the application. As shown in FIG. 3, the fast recovery diode 30 comprises 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 which are sequentially stacked; wherein the fast recovery diode 30 further comprises an N-type isolation layer 307, an N-type contact structure 308 and a trench gate structure 309, 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 and the P-type emitter 305 are juxtaposed and connected with the metal anode 306, and the trench gate structure 309 is connected with the metal anode 306 and extends into the N-type drift layer 303.

[0055] As shown in FIG. 3, and can be combined with FIG. 2 accordingly, the difference between the second embodiment and the first embodiment is mainly that, in the second embodiment, the N-type contact structure 308 is formed by N-type heavy doping process, and the doping concentration is between 1×10 17 cm -3 and 1×10 20 cm -3 The N-type contact structure 308 forms an ohmic contact.

[0056] That is to say, in the second embodiment of the present application, the first P-type body region layer 3040 and the second P-type body region layer 3041 are located on both sides of the trench gate structure 309 and connected with the trench gate structure 309, respectively; 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 connected with the trench gate structure 309, respectively; 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 connected with the trench gate structure 309, respectively. 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, respectively, 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, respectively.

[0057] The parts not described in detail in the second embodiment can be referred to the first embodiment, and the second embodiment will not be described again.

[0058]

Embodiment Three

[0059] Please refer to FIG. 4, which is a structure diagram of a fast recovery diode according to the third embodiment of the present application. As shown in FIG. 4, the fast recovery diode 40 comprises: 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, which are stacked in sequence; wherein the fast recovery diode 40 further comprises: an N-type isolation layer 407, an N-type contact structure 408 and a trench gate structure 409, 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 and the P-type emitter 405 are juxtaposed and connected with the metal anode 406, and the trench gate structure 409 is connected with the metal anode 406 and extends into the N-type drift layer 403.

[0060] As shown in Fig. 4, and can be combined with Fig. 3 accordingly, the difference between the third embodiment and the second embodiment is mainly that in the third embodiment, the first N-type contact structure 4080 and the second N-type contact structure 4081 are arranged on both sides of the trench gate structure 409 and are connected with the trench gate structure 409. That is, in the third embodiment, the first P-type emitter 4050 and the first N-type contact structure 4080 are juxtaposed and the first P-type emitter 4050 and the trench gate structure 409 are located on the opposite sides of the first N-type contact structure 4080 respectively, and the second P-type emitter 4051 and the second N-type contact structure 4081 are juxtaposed and the second P-type emitter 4051 and the trench gate structure 409 are located on the opposite sides of the second N-type contact structure 4081 respectively.

[0061] In the third embodiment, the first P-type body region layer 4040 and the second P-type body region layer 4041 are located on both sides of the trench gate structure 409 and are connected with the trench gate structure 409 respectively; 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 connected with the trench gate structure 409 respectively. 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 N-type heavy doping process, and the doping concentration is between 1x1018cm-2~1x1020cm-2. The N-type contact structure 408 forms ohmic contact. 17 cm -3 ~1x10 20 cm -3 The N-type contact structure 408 forms ohmic contact.

[0062] The unexplained parts of the third embodiment can be referred to the first embodiment and the second embodiment accordingly, and the third embodiment will not be described here.

[0063]

Embodiment Four

[0064] Please refer to Fig. 5, which is the structure schematic diagram of the fast recovery diode of the fourth embodiment of the present application. As shown in Fig. 5, the fast recovery diode 50: the metal cathode 500, the N-type substrate 501, the N-type buffer layer 502, the N-type drift layer 503, the P-type body region layer 504, the P-type emitter 505 and the metal anode 506 are stacked in turn; wherein the fast recovery diode 50 further comprises: the N-type isolation layer 507, the N-type contact structure 508 and the trench gate structure 509, 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 and the P-type emitter 505 are juxtaposed and are connected with the metal anode 506, and the trench gate structure 509 is connected with the metal anode 506 and extends into the N-type drift layer 503.

[0065] As shown in Fig. 5, and can be combined with Fig. 4 accordingly, the difference between the fourth embodiment and the third embodiment is mainly that, in the fourth embodiment, the N-type contact structure 508 is formed by an N-type doping process, and the doping concentration thereof is between 1 x 10 14 cm -3 ~ 1 x 10 17 cm -3 ; the N-type contact structure 508 can have the same doping concentration as the N-type isolation layer 507, and both can be formed by a synchronous doping process or can be formed in steps.

[0066] In the fourth embodiment, similarly, the first N-type contact structure 5080 and the second N-type contact structure 5081 are disposed on both sides of the trench gate structure 509 and are connected with the trench gate structure 509. The first P-type emitter 5050 and the trench gate structure 509 are respectively located on the 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 the opposite sides of the second N-type contact structure 5081. The first P-type body region layer 5040 and the second P-type body region layer 5041 are respectively located on both sides of the trench gate structure 509 and are connected with 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 connected with 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.

[0067] The parts of the fourth embodiment not described in detail can be referred to the first embodiment to the third embodiment accordingly, and the fourth embodiment will not be described again.

[0068] In this application, the mention of "one embodiment", "some embodiments" means that the features, structures or characteristics described in connection with the embodiment are contained in at least one embodiment, at least some embodiments of the application. Therefore, the appearance of the phrases "in one embodiment", "in some embodiments" in various places in this application does not necessarily refer to the same or the same embodiment. In addition, in one or more embodiments, the features, structures or characteristics can be combined in any suitable combination and / or sub-combination.

[0069] Although some specific embodiments of the present application have been described in detail by examples, those skilled in the art should understand that the above examples are only for illustration, not for limiting the scope of the present application. The embodiments of the present application can be combined in any combination without departing from the spirit and scope of the present 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 the present application. The scope of the present application is defined by the appended claims.

Claims

1. A fast recovery diode, characterized by, 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 layer, a P-type emitter and a metal anode which are stacked in sequence; wherein the fast recovery diode further comprises an N-type isolation layer, an N-type contact structure and a trench gate structure, the N-type isolation layer is located between the P-type body region layer and the P-type emitter, the N-type contact structure and the P-type emitter are juxtaposed and connected with the metal anode, and the trench gate structure is connected with the metal anode and extends into the N-type drift layer.

2. The fast recovery diode of claim 1 wherein, The P-type emitter comprises a first P-type emitter and a second P-type emitter, the first P-type emitter and the second P-type emitter are juxtaposed on both sides of the trench gate structure and are connected with the trench gate structure.

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

4. The fast recovery diode as described in claim 1, characterized in that, The N-type contact structure comprises a first N-type contact structure and a second N-type contact structure, the first N-type contact structure and the second N-type contact structure are juxtaposed on both sides of the trench gate structure and are connected with the trench gate structure.

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

6. The fast recovery diode according to any one of claims 1 to 5, wherein The thickness of the N-type isolation layer is between 0.5 μm and 2 μm.

7. The fast recovery diode according to any one of claims 1 to 5, wherein The N-type isolation layer has a doping concentration between 1 x 10 14 cm -3 and 1 x 10 17 cm -3 .

8. The fast recovery diode according to any one of claims 1 to 5, wherein 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 according to any one of claims 1 to 5, wherein The N-type contact structure has a doping concentration between 1 x 10 14 cm -3 and 1 x 10 20 cm -3 .

10. The fast recovery diode as described in claim 1, characterized in that, The thickness of the P-type emitter is greater than the thickness of the N-type contact structure.

11. A method of manufacturing a fast recovery diode as claimed in any one of claims 1 to 10, characterized in that, The manufacturing method of the fast recovery diode comprises: providing a semiconductor substrate and performing an ion implantation process on the semiconductor substrate to form an N-type substrate, an N-type buffer layer, an N-type drift layer, a P-type body region layer, an N-type isolation layer and a P-type emitter which are stacked in sequence, and to form an N-type contact structure which is juxtaposed with the P-type emitter; forming a trench gate structure in the semiconductor substrate, the trench gate structure extends into the N-type drift layer; and forming a metal cathode on the surface of the N-type substrate away from the N-type buffer layer, and forming a metal anode on the surface of the P-type emitter away from the P-type body region layer, the trench gate structure, the N-type contact structure and the P-type emitter are all connected with the metal anode.

12. The method for manufacturing a fast recovery diode according to claim 11, wherein The N-type contact structure and the N-type isolation layer are formed by a synchronous doping process, and the doping concentration of the N-type contact structure is the same as the doping concentration of the N-type isolation layer.

13. The method for manufacturing a fast recovery diode according to claim 11, wherein The N-type isolation layer has a doping concentration between 1 x 10 14 cm -3 and 1 x 10 17 cm -3 .

14. The method for manufacturing a fast recovery diode according to claim 11, wherein The N-type contact structure is formed by an N-type heavy doping process, and a doping concentration of the N-type contact structure is between 1 x 1019cm-3~1 x 1020cm-3. 14 cm -3 ~1 x 1020cm-3. 20 cm -3 ~1 x 1020cm-3.

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