CN116072702A - High voltage diode - Google Patents

Abstract

The application discloses a high-voltage diode, including the negative pole, N type semiconductor substrate, N type semiconductor drift layer, first oxide, first P type doped part, second oxide and positive pole, N type semiconductor substrate sets up on the negative pole, N type semiconductor drift layer sets up in N type semiconductor substrate one side of keeping away from the negative pole, first oxide is arranged in N type semiconductor substrate and extends into in partial N type semiconductor drift layer, first P type doped part sets up in N type semiconductor drift layer and is connected with first oxide, second P type doped part sets up in N type semiconductor drift layer one side of keeping away from the negative pole, second oxide is arranged in second P type doped part, and extend into partial N type semiconductor drift layer, the positive pole sets up in one side of keeping away from the negative pole of second P type doped part. In the application, by introducing the first P-type doping part, the risk of electromagnetic interference (EMI) noise generation can be reduced.

Description

High voltage diode

technical field

The present application relates to the technical field of semiconductors, in particular to a high-voltage diode.

Background technique

High-voltage diodes are usually used in inverters and are an integral part of the inverter. They play an important role in the subsequent flow of current commutation. Therefore, the speed of reverse recovery of high-voltage diodes directly affects the inverter the final efficiency.

Existing high-voltage diodes are usually obtained based on the traditional PiN structure, and heavy metal doping technology is used to control the lifespan. However, the high-voltage diodes work at high frequencies, and are prone to serious electromagnetic interference (Electromagnetic Interference, EMI) noise.

Contents of the invention

In view of this, the present application provides a high voltage diode to reduce the risk of EMI noise generation.

A high-voltage diode provided by the application includes:

cathode;

an N-type semiconductor substrate disposed on the cathode;

An N-type semiconductor drift layer disposed on a side of the N-type semiconductor substrate away from the cathode;

a first oxidation part located in the N-type semiconductor substrate and extending into a part of the N-type semiconductor drift layer;

a first P-type doped portion disposed in the N-type semiconductor drift layer and connected to the first oxide portion;

The second P-type doped part is disposed on a side of the N-type semiconductor drift layer away from the cathode;

a second oxidized part located in the second P-type doped part and extending into part of the N-type semiconductor drift layer; and

The anode is disposed on a side of the second P-type doped portion away from the cathode.

Wherein, the thickness of the anode is smaller than the thickness of the second P-type doped portion, and the first P-type doped portion is located on a side of the first oxidized portion away from the cathode.

Wherein, in the direction from one second oxidized portion to another second oxidized portion, the width of the first P-type doped portion is smaller than the width of the first oxidized portion, and the first P-type doped portion The doped part is a lightly doped part.

Wherein, the doping concentration of the first P-type doped portion is 1e14cm ⁻³ to 1e16cm ⁻³ .

Wherein, the second oxidized portion is provided in one-to-one correspondence with the first oxidized portion, and the second P-type doped portion is a lightly doped portion.

Wherein, the doping concentration of the second P-type doped portion is 1e14cm ⁻³ to 1e16cm ⁻³ .

Wherein, there are multiple first oxidized parts, and multiple first P-type doped parts, each of the first P-type doped parts is connected to one of the first oxidized parts, and every two adjacent The first P-type doped parts are arranged at intervals.

Wherein, the cross-sectional shape of the first P-type doped portion is elliptical.

Wherein, the N-type semiconductor substrate has a first trench, the first trench also extends into the N-type semiconductor drift layer, and the first trench is filled with the first oxide part.

Wherein, a first polysilicon portion is further included, the first polysilicon portion is filled in the first trench, and the first oxidized portion surrounds the first polysilicon portion.

The present application discloses a high-voltage diode, including a cathode, an N-type semiconductor substrate, an N-type semiconductor drift layer, a first oxide part, a first P-type doped part, a second P-type doped part, a second oxide 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 away 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 disposed in the N-type semiconductor drift layer and connected to the first oxidation part, the second P-type doped part is disposed on the side of the N-type semiconductor drift layer away from the cathode, and the second oxide part is located at the first oxide part. The second P-type doped part extends into a part of the N-type semiconductor drift layer, and the anode is arranged on a side of the second P-type doped part away from the cathode. In this application, by introducing the first P-type doped part connected to the first oxide part in the N-type semiconductor drift layer, the injection efficiency of back electrons can be reduced during forward conduction, thereby reducing the front hole injection efficiency. Effective injection reduces the stored carriers and accelerates the switching speed; at the same time, in the reverse bias, in the reverse recovery process, the reverse recovery current decreases after reaching the reverse peak current, and the holes will be continuously Extraction and recombination lead to a reduction in carrier concentration, and the setting of the first P-type doped part can provide continuous carriers for the N-type semiconductor drift layer, thereby reducing the possibility of a current step phenomenon in the reverse recovery phase. Risk, to further reduce the risk of electromagnetic interference EMI noise, especially in the case of high current change rate (di/dt) reverse recovery, this structure has a better suppression effect, thereby ensuring the performance of high-voltage diodes.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings that need to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application. For those skilled in the art, other drawings can also be obtained based on these drawings without any creative effort.

FIG. 1 is a schematic structural diagram of a high-voltage diode provided by the present application.

Reference signs:

10. High voltage diode; 100. Cathode; 200. N-type semiconductor substrate; 210. First groove; 300. N-type semiconductor drift layer; 400. First oxidation part; 500. First polysilicon part; 600. 700, the second P-type doped part; 710, the second trench; 800, the second oxide part; 900, the second polysilicon part; 1000, the anode.

Detailed ways

The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings. Apparently, the described embodiments are only some of the embodiments of the present application, not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without making creative efforts belong to the scope of protection of this application. In the case of no conflict, the following embodiments and technical features thereof can be combined with each other.

The present application provides a high-voltage diode, including a cathode, an N-type semiconductor substrate, an N-type semiconductor drift layer, a first oxidized part, a first P-type doped part, a second P-type doped part, a second oxidized 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 away from the cathode, the first oxidation part is located on 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 to the first oxidation part, the second P-type doped part is arranged on the side of the N-type semiconductor drift layer away from the cathode, and the second oxide part is located on the second side of the N-type semiconductor drift layer. The P-type doped part extends into part of the N-type semiconductor drift layer, and the anode is arranged on the side of the second P-type doped part away from the cathode.

In this application, by introducing the first P-type doped part connected to the first oxide part in the N-type semiconductor drift layer, the injection efficiency of back electrons can be reduced during forward conduction, thereby reducing the front hole injection efficiency. Effective injection reduces the stored carriers and accelerates the switching speed; at the same time, in the reverse bias, in the reverse recovery process, the reverse recovery current decreases after reaching the reverse peak current, and the holes will be continuously Extraction and recombination lead to a decrease in carrier concentration, and the setting of the first P-type doped part can provide continuous carriers for this region, thereby reducing the risk of current step phenomena in this stage and further reducing electromagnetic interference EMI The risk of noise, especially at high di/dt reverse recovery, the structure suppresses the effect better, thus ensuring the performance of the high voltage diode.

Please refer to FIG. 1 . FIG. 1 is a schematic structural diagram of a high voltage diode provided in the present application. The present 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 part 400, a first polysilicon part 500, a first P type doped part 600 , the second P-type doped part 700 , the second trench 710 , the second oxide part 800 , the second polysilicon part 900 and the anode 1000 .

The N-type semiconductor substrate 200 is arranged on the cathode 100. The N-type semiconductor substrate 200 is formed by doping impurity ions in a silicon film layer. The impurity ions include pentavalent elements such as phosphorus and arsenic. The N-type semiconductor substrate 200 has a first groove Groove 210 , the notch of the first groove 210 faces the cathode 100 .

The N-type semiconductor drift layer 300 is arranged 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 impurity ions in the silicon film layer. The impurity ions include pentavalent elements such as phosphorus and arsenic. A trench 210 also extends into part of the N-type semiconductor drift layer 300 .

The first oxidation part 400 is located on the N-type semiconductor substrate 200 and extends into a part of the N-type semiconductor drift layer 300 . Specifically, the first oxide portion 400 is filled in the first trench 210 .

The first P-type doped part 600 is disposed in the N-type semiconductor drift layer 300 and connected to the first oxide part 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 the silicon film layer with impurity ions, and the impurity ions include trivalent elements such as boron and aluminum. .

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 , and the second oxide portion 800 is located in the second P-type doped portion 700 and extends into part of the N-type semiconductor drift layer 300 . Specifically, the second P-type doped portion 700 is formed by doping the silicon film layer with impurity ions, and the impurity ions include trivalent elements such as boron and aluminum. The second P-type doped portion 700 has a second groove 710, and the second groove The groove 710 also extends into part of the N-type semiconductor drift layer 300 , and the notch of the second groove 710 faces one side of the anode 1000 .

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

The anode 1000 is disposed on a side of the second P-type doped portion 700 away from the cathode 100 . The anode 1000 covers the second P-type doped part 700 and the second oxidized part 800 .

In this application, by introducing the first P-type doped part 600 connected to the first oxide part 400 into the N-type semiconductor drift layer 300, the electron injection efficiency of the back side can be reduced during forward conduction, thereby reducing the front side. The effective injection of holes reduces the stored carriers and accelerates the switching speed; at the same time, in the reverse bias, in the reverse recovery process, the reverse recovery current decreases after reaching the reverse peak current, and the holes will be continuously extracted and recombined to reduce the carrier concentration, and the setting of the first P-type doped part 600 can provide continuous carriers for this region, thereby reducing the risk of current step phenomenon in this stage, and further The risk of EMI noise is reduced, especially in high di/dt reverse recovery, the suppression effect of this structure is better, thereby ensuring the performance of the high voltage diode 10 .

In one embodiment, the thickness of the anode 1000 is smaller than that of the second P-type doped portion 700 , and the first P-type doped portion 600 is located on a 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 .

In the present application, disposing the first P-type doped portion 600 between the first oxidized portion 400 and the first P-type doped portion 600 can further reduce the injection efficiency of backside electrons during forward conduction. It can further reduce the effective injection of positive holes, so that the stored carriers are reduced and the switching speed is accelerated; at the same time, it can further make the reverse recovery current reach the reverse peak value in the reverse recovery process under reverse bias In the current falling stage, the holes will be continuously extracted and recombined to reduce the carrier concentration, and the setting of the first P-type doped part 600 can provide continuous carriers for this region, thereby reducing the current in this stage. The risk of the step phenomenon further reduces the generation of EMI and ensures the performance of the high voltage diode 10 ; setting the thickness of the anode 1000 to be smaller than the thickness of the second P-type doped part 700 can reduce the cost of the high voltage diode 10 .

In another embodiment, the first P-type doped portion 600 is located on a side of the first oxidized portion 400 close to the other oxidized portion, that is, the first P-type doped portion 600 is not located between the first oxidized portion 400 and the second oxidized portion. between a P-type doped portion 600 .

In the present application, disposing the first P-type doped portion 600 between the first oxidized portion 400 and the first P-type doped portion 600 can further reduce the injection efficiency of backside electrons during forward conduction. It can further reduce the effective injection of positive holes, so that the stored carriers are reduced and the switching speed is accelerated; at the same time, it can further make the reverse recovery current reach the reverse peak value in the reverse recovery process under reverse bias In the current falling stage, the holes will be continuously extracted and recombined to reduce the carrier concentration, and the setting of the first P-type doped part 600 can provide continuous carriers for this region, thereby reducing the current in this stage. The risk of the step phenomenon further reduces the risk of EMI noise and ensures the performance of the high voltage diode 10 .

In one embodiment, in the direction from one second oxidized portion 800 to another second oxidized portion 800, the width w1 of the first P-type doped portion 600 is smaller than the width w2 of the first oxidized portion 400, and the first P-type The doped part 600 is a lightly doped part. 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 in the dynamic process An appropriate amount of holes is provided to suppress the current step phenomenon; if the first P-type doped part 600 is set as a heavily doped structure, the dynamic avalanche capability of the high voltage diode 10 will be reduced due to the high doping concentration.

In an 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 portion 600 may be 1e14cm ⁻³ , 1e15cm ⁻³ or 1e16cm ⁻³ , etc.

In this application, the doping concentration of the first P-type doped part 600 is set to 1e14cm-3~1e16cm-3, which further provides an appropriate amount of holes in the dynamic process to suppress the current step phenomenon; if the first The P-type doped part 600 is set to be larger than this range, and the doping concentration is higher, which will reduce the dynamic avalanche capability of the high voltage diode 10 .

In one embodiment, the second oxidized portion 800 is provided in one-to-one correspondence with the first oxidized portion 400 , and the second P-type doped portion 700 is a lightly doped portion. The second P-type doped part 700 is set as a lightly doped part, so that the injection efficiency of front holes can be further reduced, thereby increasing the reverse recovery speed.

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 may be 1e14cm ⁻³ , 1e15cm ⁻³ or 1e16cm ⁻³ .

In this application, the doping concentration of the second P-type doped portion 700 is set to 1e14cm-3˜1e16cm-3, so that the injection efficiency of front holes can be further reduced, thereby increasing the reverse recovery speed.

In one embodiment, there are multiple first oxidized parts 400, and multiple first P-type doped parts 600, and each first P-type doped part 600 is connected to a first oxidized part 400, and every two adjacent The first P-type doped parts 600 are arranged at intervals.

In this application, every two adjacent first P-type doped parts 600 are arranged at intervals, so as to provide a normal channel for the electrons injected on the back side, avoiding the voltage drop affecting the forward conduction, thereby ensuring the high-voltage diode 10 performance.

In one embodiment, the distance between every two adjacent first P-type doped portions 600 is equal.

In this application, the distance between every two adjacent first P-type doped parts 600 is set to be equal, so that EMI noise can be suppressed, and the preparation method of the first P-type doped part 600 is simplified. Thereby reducing costs.

In one embodiment, the cross-sectional shape of the first P-type doped portion 600 is an ellipse. In this application, the cross-sectional shape of the first P-type doped part 600 is elliptical, so that EMI noise can be suppressed, and the preparation method of the first P-type doped part 600 is simplified, thereby simplifying the high-voltage diode 10. preparation method, thereby reducing costs.

In another embodiment, the cross-sectional shape of the first P-type doped portion 600 may also be a circle, a square or a triangle, etc., which is not limited here. The shape of the first P-type doped part 600 is set to this design, so that EMI noise can be further suppressed, and at the same time, the preparation method of the first P-type doped part 600 is simplified, thereby simplifying the preparation method of the high-voltage diode 10, Thereby reducing costs.

In another embodiment, there are multiple first oxidized parts 400, multiple first P-type doped parts 600, and multiple first P-type doped parts 600 arranged at intervals are connected to a first oxidized part 400, That is, a plurality of first P-type doped parts 600 arranged at intervals are arranged around the first oxide part 400, and the first P-type doped parts 600 are not only arranged on the side of the first oxide part 400 close to the second oxide part 800, but also It is disposed on the side of the second oxidation part 800 .

In this application, a first oxidized part 400 is provided with a plurality of first P-type doped parts 600 connected thereto, so that EMI noise can be suppressed, and at the same time, a normal channel can be provided for electrons injected from the back side, thereby The voltage drop affecting forward conduction is further avoided, thereby ensuring the performance of the high voltage diode 10 .

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

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

In an embodiment, the high voltage diode 10 provided in the present application may be an insulated gate bipolar transistor (Insulated Gate Bipolar Transistor, IGBT) or a fast recovery diode (Fast Recovery Diode, FRD).

The present application provides a high-voltage diode 10. By introducing a first P-type doped part 600 connected to the first oxide part 400 into the N-type semiconductor drift layer 300, the injection efficiency of back electrons can be reduced during forward conduction. Thus, the effective injection of positive holes can be reduced, the stored carriers are reduced, and the switching speed is accelerated; at the same time, in the reverse bias, in the reverse recovery process, the reverse recovery current decreases after reaching the reverse peak current stage, the holes will be continuously extracted and recombined to reduce the carrier concentration, and the setting of the first P-type doped part 600 can provide continuous carriers for the N-type semiconductor drift layer, thereby reducing the reverse recovery The risk of current step phenomenon in the stage can further reduce the generation of EMI noise, especially in the case of high di/dt reverse recovery, the suppression effect of this structure is better, thereby ensuring the performance of the high voltage diode 10 .

The above is only an embodiment of the application, and does not limit the patent scope of the application. Any equivalent structure or equivalent process conversion made by using the specification and accompanying drawings of the application, such as the mutual technical characteristics between the various embodiments Combination, or direct or indirect application in other related technical fields, are all included in the scope of patent protection of this application.

Claims (10)

1. A high voltage diode, comprising:

a cathode;

an N-type semiconductor substrate arranged on the cathode;

the N-type semiconductor drift layer is arranged on one side of the N-type semiconductor substrate, which is far away from the cathode;

a first oxide portion located in the N-type semiconductor substrate and extending into a portion of the N-type semiconductor drift layer;

a first P-type doped portion disposed in the N-type semiconductor drift layer and connected to the first oxide portion;

the second P-type doping part is arranged on one side of the N-type semiconductor drift layer, which is far away from the cathode;

a second oxide part located in the second P-type doped part and extending into part of the N-type semiconductor drift layer; and

and the anode is arranged at one side of the second P-type doping part far away from the cathode.

2. The high voltage diode of claim 1, wherein the anode has a thickness less than a thickness of the second P-type doped portion, the first P-type doped portion being located on a side of the first oxide portion remote from the cathode.

3. The high voltage diode of claim 2, wherein the width of the first P-type doped portion is smaller than the width of the first oxide portion in a direction from one of the second oxide portions to the other of the second oxide portions, the first P-type doped portion being a lightly doped portion.

4. The high voltage diode of claim 3, wherein the doping concentration of the first P-type doping is 1e14cm ^-3 ～1e16cm ^-3 。

5. The high voltage diode of claim 4, wherein the second oxide portions are disposed in one-to-one correspondence with the first oxide portions, and the second P-type doped portions are lightly doped portions.

6. The high voltage diode of claim 5, wherein the second P-type dopant has a dopant concentration of 1e14cm ^-3 ～1e16cm ^-3 。

7. The high voltage diode as recited in claim 6, wherein said first oxide portion is connected to one of said first oxide portions, and each two adjacent ones of said first P-type doped portions are spaced apart.

8. The high voltage diode of claim 7, wherein the first P-type doped portion has an elliptical cross-sectional shape.

9. The high voltage diode of any one of claims 1 to 8, wherein the N-type semiconductor substrate has a first trench that also extends into the N-type semiconductor drift layer, the first trench being filled with the first oxide.

10. The high voltage diode of claim 9, further comprising a first polysilicon portion filled in the first trench, the first oxide portion surrounding the first polysilicon portion.

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