High-voltage diode

Abstract

The application discloses a high-voltage diode, which comprises a cathode, an N-type semiconductor substrate, an N-type semiconductor drift layer, a first oxidation part, a first P-type doped part, a second P-type doped part, a second oxidation part and an anode. The N-type semiconductor substrate is arranged on the cathode. The N-type semiconductor drift layer is arranged on the side of the N-type semiconductor substrate far from the cathode. The first oxidation part is located in the N-type semiconductor substrate and extends into part of the N-type semiconductor drift layer. The first P-type doped part is arranged in the N-type semiconductor drift layer and connected with the first oxidation part. The second P-type doped part is arranged on the side of the N-type semiconductor drift layer far from the cathode. The second oxidation part is located in the second P-type doped part and extends into part of the N-type semiconductor drift layer. The anode is arranged on the side of the second P-type doped part far from the cathode. In the application, the risk of electromagnetic interference (EMI) noise generation can be reduced by introducing the first P-type doped part.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, specifically to a high-voltage diode. Background Technology

[0002] High-voltage diodes are commonly used in inverters and are an indispensable part of inverters. They play an important role in switching current to subsequent current. Therefore, the speed of reverse recovery of high-voltage diodes directly affects the final efficiency of inverters.

[0003] Existing high-voltage diodes are typically based on traditional PiN structures and use heavy metal doping technology to control their lifetime. However, these high-voltage diodes operate at high frequencies and are prone to severe electromagnetic interference (EMI) noise. Summary of the Invention

[0004] In view of this, this application provides a high-voltage diode to reduce the risk of EMI noise generation.

[0005] This application provides a high-voltage diode, comprising:

[0006] cathode;

[0007] An N-type semiconductor substrate is disposed on the cathode;

[0008] An N-type semiconductor drift layer is disposed on the side of the N-type semiconductor substrate away from the cathode;

[0009] The first oxide portion is located in the N-type semiconductor substrate and extends into a portion of the N-type semiconductor drift layer;

[0010] A first P-type doped portion is disposed in the N-type semiconductor drift layer and connected to the first oxide portion;

[0011] The second P-type doped portion is disposed on the side of the N-type semiconductor drift layer away from the cathode;

[0012] The second oxide portion is located within the second P-type doped portion and extends into a portion of the N-type semiconductor drift layer; and

[0013] The anode is located on the side of the second P-type doped region away from the cathode.

[0014] The thickness of the anode is less than the thickness of the second P-type doped portion, and the first P-type doped portion is located on the side of the first oxide portion away from the cathode.

[0015] In the direction from one second oxide portion to another second oxide portion, the width of the first P-type doped portion is smaller than the width of the first oxide portion, and the first P-type doped portion is a lightly doped portion.

[0016] The doping concentration of the first P-type doped portion is 1e14cm. -3 ~1e16cm -3 .

[0017] The second oxide portion is provided in a one-to-one correspondence with the first oxide portion, and the second P-type doped portion is a lightly doped portion.

[0018] The doping concentration of the second P-type doped portion is 1e14cm. -3 ~1e16cm -3 .

[0019] The first oxide portion has multiple portions, the first P-type doped portion has multiple portions, each first P-type doped portion is connected to a first oxide portion, and each pair of adjacent first P-type doped portions are spaced apart.

[0020] The cross-sectional shape of the first P-type doped portion is elliptical.

[0021] The N-type semiconductor substrate has a first trench that extends into the N-type semiconductor drift layer and is filled with the first oxide portion.

[0022] It also includes a first polysilicon portion, which fills the first trench, and a first oxide portion surrounds the first polysilicon portion.

[0023] This application discloses a high-voltage diode, including a cathode, an N-type semiconductor substrate, an N-type semiconductor drift layer, a first oxide portion, a first P-type doped portion, a second P-type doped portion, a second oxide portion, and an anode. The N-type semiconductor substrate is disposed on the cathode, the N-type semiconductor drift layer is disposed on the side of the N-type semiconductor substrate away from the cathode, the first oxide portion is located in the N-type semiconductor substrate and extends into a portion of the N-type semiconductor drift layer, the first P-type doped portion is disposed in the N-type semiconductor drift layer and connected to the first oxide portion, the second P-type doped portion is disposed on the side of the N-type semiconductor drift layer away from the cathode, the second oxide portion is located in the second P-type doped portion and extends into a portion of the N-type semiconductor drift layer, and the anode is disposed on the side of the second P-type doped portion away from the cathode. In this application, by introducing a first P-type doped portion connected to the first oxide portion into the N-type semiconductor drift layer, the injection efficiency of electrons on the back side can be reduced during forward conduction, thereby reducing the effective injection of holes on the front side, reducing the number of stored charge carriers, and accelerating the switching speed. At the same time, during reverse bias, in the reverse recovery process, after the reverse recovery current reaches the reverse peak current and then decreases, holes are continuously extracted and recombine, leading to a decrease in the charge carrier concentration. The first P-type doped portion can provide the N-type semiconductor drift layer with a continuous supply of charge carriers, thereby reducing the risk of current step phenomenon during the reverse recovery stage and further reducing the risk of electromagnetic interference (EMI) noise generation. Especially during high current change rate (di / dt) reverse recovery, the suppression effect of this structure is better, thus ensuring the performance of the high-voltage diode. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the high-voltage diode provided in this application.

[0026] Figure label:

[0027] 10. High voltage diode; 100. Cathode; 200. N-type semiconductor substrate; 210. First trench; 300. N-type semiconductor drift layer; 400. First oxide layer; 500. First polysilicon layer; 600. First P-type doped layer; 700. Second P-type doped layer; 710. Second trench; 800. Second oxide layer; 900. Second polysilicon layer; 1000. Anode. Detailed Implementation

[0028] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. In the absence of conflict, the following embodiments and their technical features can be combined with each other.

[0029] This application provides a high-voltage diode, including a cathode, an N-type semiconductor substrate, an N-type semiconductor drift layer, a first oxide portion, a first P-type doped portion, a second P-type doped portion, a second oxide portion, and an anode. The N-type semiconductor substrate is disposed on the cathode, the N-type semiconductor drift layer is disposed on the side of the N-type semiconductor substrate away from the cathode, the first oxide portion is located in the N-type semiconductor substrate and extends into a portion of the N-type semiconductor drift layer, the first P-type doped portion is disposed in the N-type semiconductor drift layer and connected to the first oxide portion, the second P-type doped portion is disposed on the side of the N-type semiconductor drift layer away from the cathode, the second oxide portion is located in the second P-type doped portion and extends into a portion of the N-type semiconductor drift layer, and the anode is disposed on the side of the second P-type doped portion away from the cathode.

[0030] In this application, by introducing a first P-type doped portion connected to the first oxide portion into the N-type semiconductor drift layer, the injection efficiency of electrons on the back side can be reduced during forward conduction, thereby reducing the effective injection of holes on the front side, reducing the number of stored charge carriers, and accelerating the switching speed. At the same time, during reverse bias, in the reverse recovery process, after the reverse recovery current reaches the reverse peak current and then decreases, holes are continuously extracted and recombine, leading to a decrease in the charge carrier concentration. The first P-type doped portion can provide a continuous supply of charge carriers to this region, thereby reducing the risk of current step phenomenon during this stage and further reducing the risk of electromagnetic interference (EMI) noise generation. Especially during high di / dt reverse recovery, the suppression effect of this structure is better, thus ensuring the performance of the high-voltage diode.

[0031] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of the high-voltage diode provided in this application. This application provides a high-voltage diode 10, including a cathode 100, an N-type semiconductor substrate 200, a first trench 210, an N-type semiconductor drift layer 300, a first oxide portion 400, a first polysilicon portion 500, a first P-type doped portion 600, a second P-type doped portion 700, a second trench 710, a second oxide portion 800, a second polysilicon portion 900, and an anode 1000.

[0032] An N-type semiconductor substrate 200 is disposed on a cathode 100. The N-type semiconductor substrate 200 is formed by doping a silicon film layer with impurity ions, including pentavalent elements such as phosphorus and arsenic. The N-type semiconductor substrate 200 has a first trench 210, with the opening of the first trench 210 facing the cathode 100.

[0033] The N-type semiconductor drift layer 300 is disposed on the side of the N-type semiconductor substrate 200 away from the cathode 100. The N-type semiconductor drift layer 300 is formed by doping a silicon film layer with impurity ions, including pentavalent elements such as phosphorus and arsenic. The first trench 210 also extends into a portion of the N-type semiconductor drift layer 300.

[0034] The first oxide portion 400 is located on the N-type semiconductor substrate 200 and extends into a portion of the N-type semiconductor drift layer 300. Specifically, the first oxide portion 400 fills the first trench 210.

[0035] The first P-type doped portion 600 is disposed in the N-type semiconductor drift layer 300 and connected to the first oxide portion 400. Specifically, the first P-type doped portion 600 is connected to the sidewall of the first trench 210, and the first P-type doped portion 600 is formed by doping a silicon film layer with impurity ions, including trivalent elements such as boron and aluminum.

[0036] The second P-type doped portion 700 is disposed on the side of the N-type semiconductor drift layer 300 away from the cathode 100. The second oxide portion 800 is located in the second P-type doped portion 700 and extends into a portion of the N-type semiconductor drift layer 300. Specifically, the second P-type doped portion 700 is formed by doping a silicon film layer with impurity ions, including trivalent elements such as boron and aluminum. The second P-type doped portion 700 has a second trench 710, which also extends into a portion of the N-type semiconductor drift layer 300. The opening of the second trench 710 faces the anode 1000.

[0037] The second oxide portion 800 is filled in the second trench 710. The second polysilicon portion 900 is filled in the second trench 710 and is surrounded by the second oxide portion 800. The second oxide portion 800 and the first P-type doped portion 600 are separated by the N-type semiconductor drift layer 300, that is, the second oxide portion 800 and the first P-type doped portion 600 are spaced apart.

[0038] The anode 1000 is disposed on the side of the second P-type doped portion 700 away from the cathode 100. The anode 1000 covers the second P-type doped portion 700 and the second oxide portion 800.

[0039] In this application, by introducing a first P-type doped portion 600 connected to the first oxide portion 400 in the N-type semiconductor drift layer 300, the injection efficiency of electrons on the back side can be reduced during forward conduction, thereby reducing the effective injection of holes on the front side, reducing the number of stored charge carriers, and accelerating the switching speed. At the same time, during reverse bias, in the reverse recovery process, after the reverse recovery current reaches the reverse peak current and then decreases, holes are continuously extracted and recombine, resulting in a decrease in the charge carrier concentration. The first P-type doped portion 600 can provide a continuous supply of charge carriers to this region, thereby reducing the risk of current step phenomenon during this stage and further reducing the risk of EMI noise generation. Especially during high di / dt reverse recovery, the suppression effect of this structure is better, thus ensuring the performance of the high voltage diode 10.

[0040] In one embodiment, the thickness of the anode 1000 is less than the thickness of the second P-type doped portion 700, and the first P-type doped portion 600 is located on the side of the first oxide portion 400 away from the cathode 100. Specifically, the first P-type doped portion 600 is located between the first oxide portion 400 and the first P-type doped portion 600.

[0041] In this application, the first P-type doped portion 600 is disposed between the first oxide portion 400 and the first P-type doped portion 600. This further reduces the injection efficiency of electrons from the back side during forward conduction and further reduces the effective injection of holes from the front side, resulting in fewer stored charge carriers and faster switching speed. Simultaneously, during reverse bias, in the reverse recovery process, after the reverse recovery current reaches the reverse peak current and decreases, holes are continuously extracted and recombine, leading to a decrease in charge carrier concentration. The first P-type doped portion 600 can provide a continuous supply of charge carriers to this region, thereby reducing the risk of current step phenomena during this stage, further reducing EMI generation, and ensuring the performance of the high-voltage diode 10. Setting the thickness of the anode 1000 to be less than the thickness of the second P-type doped portion 700 can reduce the cost of the high-voltage diode 10.

[0042] In another embodiment, the first P-type doped portion 600 is located on the side of a first oxide portion 400 near another oxide portion, that is, the first P-type doped portion 600 is not located between the first oxide portion 400 and the first P-type doped portion 600.

[0043] In this application, the first P-type doped portion 600 is disposed between the first oxide portion 400 and the first P-type doped portion 600. This further reduces the injection efficiency of electrons on the back side during forward conduction and further reduces the effective injection of holes on the front side, thereby reducing the number of stored charge carriers and accelerating the switching speed. At the same time, during reverse bias, in the reverse recovery process, after the reverse recovery current reaches the reverse peak current and then decreases, holes are continuously extracted and recombine, leading to a decrease in the charge carrier concentration. The placement of the first P-type doped portion 600 can provide a continuous supply of charge carriers to this region, thereby reducing the risk of current step phenomena during this stage, further reducing the risk of EMI noise generation, and ensuring the performance of the high-voltage diode 10.

[0044] In one embodiment, in the direction from one second oxide portion 800 to another second oxide portion 800, the width w1 of the first P-type doped portion 600 is smaller than the width w2 of the first oxide portion 400, and the first P-type doped portion 600 is a lightly doped portion. In this application, the first P-type doped portion 600 is set as a lightly doped portion, and the width w1 of the first P-type doped portion 600 is set to be smaller than the width w2 of the first oxide portion 400, so that an appropriate amount of holes is provided during dynamic processes to suppress current step phenomena; if the first P-type doped portion 600 is set as a heavily doped structure, the high doping concentration will lead to a reduction in the dynamic avalanche capability of the high-voltage diode 10.

[0045] In one embodiment, the doping concentration of the first P-type doped portion 600 is 1e14cm. -3 ~1e16cm -3 Specifically, the doping concentration of the first P-type doped region 600 can be 1e14cm. -3 1e15cm -3 Or 1e16cm -3 wait.

[0046] In this application, the doping concentration of the first P-type doped portion 600 is set to 1e14cm-3 to 1e16cm-3, which further provides an appropriate amount of holes during dynamic processes to suppress current step phenomena. If the first P-type doped portion 600 is set to a range greater than this, the doping concentration will be higher, which will lead to a reduction in the dynamic avalanche capability of the high voltage diode 10.

[0047] In one embodiment, the second oxide portion 800 is configured in a one-to-one correspondence with the first oxide portion 400, and the second P-type doped portion 700 is a lightly doped portion. By configuring the second P-type doped portion 700 as a lightly doped portion, the injection efficiency of front-side holes can be further reduced, thereby improving the reverse recovery speed.

[0048] In one embodiment, the doping concentration of the second P-type doped portion 700 is 1e14cm. -3~1e16cm -3 Specifically, the doping concentration of the second P-type doped portion 700 can be 1e14cm. -3 1e15cm -3 Or 1e16cm -3 wait.

[0049] In this application, the doping concentration of the second P-type doped portion 700 is set to 1e14cm-3 to 1e16cm-3, which can further reduce the injection efficiency of front-side holes, thereby improving the reverse recovery speed.

[0050] In one embodiment, there are multiple first oxide portions 400 and multiple first P-type doped portions 600. Each first P-type doped portion 600 is connected to a first oxide portion 400, and every two adjacent first P-type doped portions 600 are spaced apart.

[0051] In this application, each pair of adjacent first P-type doped portions 600 are spaced apart to provide a normal channel for electrons injected from the back side, avoiding affecting the forward voltage drop and thus ensuring the performance of the high-voltage diode 10.

[0052] In one embodiment, the distance between any two adjacent first P-type doped portions 600 is equal.

[0053] In this application, the distance between any two adjacent first P-type doped portions 600 is set to be equal, which can suppress the generation of EMI noise and simplify the preparation method of the first P-type doped portion 600, thereby reducing costs.

[0054] In one embodiment, the cross-sectional shape of the first P-type doped portion 600 is elliptical. In this application, the elliptical cross-sectional shape of the first P-type doped portion 600 can suppress EMI noise generation while simplifying the fabrication method of the first P-type doped portion 600, thereby simplifying the fabrication method of the high-voltage diode 10 and reducing costs.

[0055] In another embodiment, the cross-sectional shape of the first P-type doped portion 600 can also be circular, square, or triangular, etc., and is not limited here. Setting the shape of the first P-type doped portion 600 in this way can further suppress the generation of EMI noise, while simplifying the fabrication method of the first P-type doped portion 600, thereby simplifying the fabrication method of the high-voltage diode 10 and reducing costs.

[0056] In another embodiment, there are multiple first oxide portions 400 and multiple first P-type doped portions 600. Multiple first P-type doped portions 600 are spaced apart and connected to a first oxide portion 400. That is, multiple spaced first P-type doped portions 600 are arranged around the first oxide portion 400. The first P-type doped portions 600 are not only arranged on the side of the first oxide portion 400 near the second oxide portion 800, but also on the side of the second oxide portion 800.

[0057] In this application, a first oxide portion 400 is provided with a plurality of first P-type doped portions 600 connected thereto, which can suppress the generation of EMI noise and further provide a normal channel for electrons injected from the back side, thereby further avoiding affecting the forward conduction voltage drop and thus ensuring the performance of the high voltage diode 10.

[0058] In one embodiment, the first trench 210 extends into the N-type semiconductor drift layer 300 to a greater depth than the second trench 710 extends into the N-type semiconductor drift layer 300, so as to further suppress the generation of EMI noise.

[0059] It should be noted that some structures in this application can be removed as needed, such as the second oxide part 800 and the second trench 710.

[0060] In one embodiment, the high-voltage diode 10 provided in this application can be an insulated gate bipolar transistor (IGBT) or a fast recovery diode (FRD), etc.

[0061] This application provides a high-voltage diode 10. By introducing a first P-type doped portion 600 connected to a first oxide portion 400 in an N-type semiconductor drift layer 300, the injection efficiency of electrons on the back side can be reduced during forward conduction, thereby reducing the effective injection of holes on the front side, reducing the number of stored charge carriers, and accelerating the switching speed. At the same time, during reverse bias, in the reverse recovery process, after the reverse recovery current reaches the reverse peak current and then decreases, holes are continuously extracted and recombine, leading to a decrease in the charge carrier concentration. The first P-type doped portion 600 can provide a continuous supply of charge carriers to the N-type semiconductor drift layer, thereby reducing the risk of current step phenomenon during the reverse recovery stage and further reducing the generation of EMI noise. Especially during high di / dt reverse recovery, the suppression effect of this structure is better, thus ensuring the performance of the high-voltage diode 10.

[0062] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, such as the combination of technical features between embodiments, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A high-voltage diode, characterized in that, include: cathode; An N-type semiconductor substrate is disposed on the cathode; An N-type semiconductor drift layer is disposed on the side of the N-type semiconductor substrate away from the cathode; The first oxide portion is located in the N-type semiconductor substrate and extends into a portion of the N-type semiconductor drift layer; A first P-type doped portion is disposed in the N-type semiconductor drift layer and connected to the first oxide portion; The second P-type doped portion is disposed on the side of the N-type semiconductor drift layer away from the cathode; The second oxide portion is located in the second P-type doped portion and extends into a portion of the N-type semiconductor drift layer. In the direction from one second oxide portion to another, the width of the first P-type doped portion is smaller than the width of the first oxide portion. The first P-type doped portion is a lightly doped portion. There are multiple first oxide portions and multiple first P-type doped portions. Each first P-type doped portion is connected to a first oxide portion. Every two adjacent first P-type doped portions are spaced apart. The cross-sectional shape of the first P-type doped portion is elliptical. as well as The anode is located on the side of the second P-type doped region away from the cathode.

2. The high-voltage diode according to claim 1, characterized in that, The thickness of the anode is less than the thickness of the second P-type doped portion, and the first P-type doped portion is located on the side of the first oxide portion away from the cathode.

3. The high-voltage diode according to claim 1, characterized in that, The doping concentration of the first P-type doped portion is 1e14cm. -3 ~1e16cm -3 .

4. The high-voltage diode according to claim 1, characterized in that, The second oxide portion is provided in a one-to-one correspondence with the first oxide portion, and the second P-type doped portion is a lightly doped portion.

5. The high-voltage diode according to claim 1, characterized in that, The doping concentration of the second P-type doped portion is 1e14cm. -3 ~1e16cm -3 .

6. The high-voltage diode according to any one of claims 1 to 5, characterized in that, The N-type semiconductor substrate has a first trench that extends into the N-type semiconductor drift layer, and the first trench is filled with the first oxide portion.

7. The high-voltage diode according to claim 6, characterized in that, It also includes a first polysilicon portion, which fills the first trench, and a first oxide portion surrounding the first polysilicon portion.

Images