Self-protection electrically controlled thyristor capable of accurately controlling breakover voltage

Abstract

According to the self-protection electrically-controlled thyristor capable of accurately controlling the breakover voltage, a sinking distortion junction with a proper depth is manufactured at a forward blocking junction below an effective cathode region of an amplification gate electrode front auxiliary thyristor, so that the thickness of a long base region of the front thyristor is reduced, and a fixed region for forward voltage breakover starting is formed. The turning current in the area is equal to the gate pole strong trigger current entering the amplification gate pole area, and is sufficient to implement strong trigger on the main thyristor, so that the main thyristor enters a safety mode of opening the amplification gate pole-cathode perimeter, the thyristor has a self-trigger protection function on forward voltage turning, the size and the shape of a sinking distortion junction are accurately designed, and the reliability of the device is improved. And the breakover voltage of the device can be accurately controlled. The overvoltage self-protection device has the advantages that an overvoltage self-protection function is integrated in the device, tedious external circuit triggering protection is not needed, a thyristor application circuit is greatly simplified, and the reliability of a power electronic device is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of design and manufacturing of high-power semiconductor devices, and specifically relates to a 4-inch 2500A / 4200V precision turning electrically controlled thyristor. Background Art

[0002] As we all know, ordinary electrically controlled thyristor semiconductor chips consist of four layers, three junctions, and three terminals, such as Figure 1 As shown, thyristors have the following special properties: The thyristor semiconductor chip has the ability to block the current in the forward direction. When the voltage of the anode A is higher than the voltage of the cathode K, the J2 junction inside the thyristor semiconductor chip is reverse biased, and the space charge layer of the J2 junction expands, forming a strong electric field, which hinders the flow of most carriers. Only a very small number of carriers flow through, forming a very small leakage current (a few milliamperes). Thyristor semiconductor chips also have reverse blocking current capability. When the anode A voltage is lower than the cathode K voltage, the J1 and J3 junctions inside the thyristor semiconductor chip are reverse biased. Since the concentrations on both sides of the J3 junction are high, the breakdown voltage is very low. The main role is played by the J1 junction. The space charge layer of the J1 junction expands to form a strong electric field, which hinders the flow of most carriers. Only a very small number of carriers flow through, forming a very small leakage current (several milliamperes).

[0003] In addition to the above two characteristics, thyristors have another most valuable characteristic, called the control electrode trigger characteristic. When a very small current (tens to hundreds of mA) flows from the control electrode to the cathode, the forward transition voltage will drop until it is fully turned on, and a current of hundreds to thousands of amperes flows from the anode. The control electrode provides us with the condition of controlling a large power with a very small power, and is an ideal high-power switching device.

[0004] However, when there is no control electrode trigger signal, when the forward blocking voltage of ordinary electric-controlled thyristors is too high, a transient large current often appears in the weakest area of ​​the withstand voltage link, entering a dangerous local turn-on mode. If the current can expand the entire device in time, the thyristor will not be burned immediately, but the long-term heat accumulation effect will also deteriorate the performance of the thyristor; if the current does not expand in time, the thyristor will be burned immediately. In order to avoid these two failures, the traditional preventive measure is to set a testing control protection unit (TCU) outside the electric-controlled thyristor, referred to as TCU trigger protection mode. The working process of this mode is as follows: (1) The forward voltage across the thyristor is detected through the TCU unit; (2) It is compared with a set reference voltage value (this value is lower than the thyristor turn-on voltage); (3) If the detection value is greater than or equal to the set value, the TCU gives a thyristor gate trigger signal; (4) The thyristor is guided to trigger and conduct safely, thereby effectively protecting the thyristor and its main circuit.

[0005] Since the TCU detection control protection unit is completely set outside the thyristor, it requires a large number of electronic components and circuits. Due to the loss and line sense of a large number of electronic components and circuits, the detection and protection are extremely insensitive, often burning the thyristor, which in turn causes the collapse of the entire device, causing huge losses. Therefore, not only does it increase the cost of the device, but also because each step of the protection trigger control unit requires time to analyze, compare, and trigger, the response is extremely slow, and it often cannot effectively protect the thyristor, resulting in a decrease in the reliability and stability of the device system. Summary of the invention

[0006] The present invention provides a self-protection electrically controlled thyristor for accurately controlling the breakover voltage, which has high detection and protection sensitivity and solves the shortcomings of the thyristor in the prior art, such as low utilization efficiency, poor reliability and high cost.

[0007] The technical solution adopted by the present invention is: a self-protection electrically controlled thyristor with precise control of the turning voltage, which, viewed from the horizontal direction, is composed of a central gate, an amplifying gate, an amplifying gate extension line segment and an amplifying gate extension branch, a cathode, a table and an anode on the back; the central gate is located in the center of the device and is circular; an amplifying gate is provided at the outer end of the central gate in a circular ring shape; the amplifying gate is provided with amplifying gate extension line segments along six directions, and a V-shaped amplifying gate extension branch is connected to the end of each amplifying gate extension line segment, and the end is an arc shape; the amplifying gate extension line segment and the amplifying gate extension branch penetrate into the cathode to evenly separate the cathode area; a first isolation groove is provided between the central gate and the amplifying gate; a second isolation groove is provided between the amplifying gate and its amplifying gate extension line segment, the amplifying gate extension branch and the cathode; a circular table is provided at the outermost end of the device, which is connected to the cathode; From the vertical perspective, it is a four-layer three-terminal structure, with the four layers being N2, P - +P2 layer, N1 layer, P1 layer; the three terminals refer to A terminal, K terminal, and G terminal; the device is symmetrical about the y axis; Create a P with appropriate width and depth in the forward blocking region below the amplifier gate. - Layer sunken ring mutation knot, the P - The layer-depression blocking junction is doped with aluminum ions, with a surface concentration of 1-2×10 21 Pieces / cm 3 , width is 2±0.1cm, depth is 20±5µm; the size of the abrupt junction accurately controls the size of the through channel, which in turn determines the size of the short-circuit current, thereby accurately controlling the turning voltage.

[0008] Furthermore, the N2 layer is doped with phosphorus at a concentration of 1-2×10 25 Pieces / cm 3 , with a depth of 25±2µm; the P1 layer and the P2 layer are doped with the same impurity aluminum element, with a concentration of 4-6×1021 Pieces / cm 3 , depth is 95±5µm; N1 layer is zone melting high resistance silicon single crystal, resistivity is 500±7%Ω.cm; concentration is 1-2×10 19 Pieces / cm 3 , thickness is 1250±10µm, crystal orientation is <111> .

[0009] Furthermore, the central gate electrode is a P-shaped circle with a diameter of 4±0.01 mm, and the surface is covered with aluminum electrode material.

[0010] Furthermore, the amplifying gate is composed of two circular rings, one of which is an N-type circular ring: the inner diameter is 3.5±0.01cm and the outer diameter is 4.5±0.01cm; the other circular ring is a P-type circular ring, the inner diameter is 4.5±0.01cm and the outer diameter is 5.5±0.01cm; the two circular rings are covered with aluminum electrode material.

[0011] Furthermore, the amplifying gate extension line segment is composed of 6 P-type line segments, the width close to the amplifying gate is 1.0mm±0.01mm, and is connected to the P-type ring of the amplifying gate; the part away from the amplifying gate is 0.3mm±0.01mm, and the width gradually decreases; and at the end of the amplifying gate extension line segment, it is divided into a V-shaped amplifying gate extension branch, and the P-type doping width gradually decreases from 0.3mm±0.01mm to 0.2±0.01mm; the amplifying gate extension line segment and the amplifying gate extension branch are covered with aluminum electrode material, and are connected to the aluminum electrode material of the amplifying gate.

[0012] Furthermore, the cathode 4 is an N-type doped region, on which P-type dots with a diameter of 0.1±0.01 mm are evenly distributed, and are connected to the P2 layer below the N-type doped region to form a P-type short-circuit channel. The cathode is connected to the amplifying gate and its amplifying gate extension line segment and the outer end of the amplifying gate extension branch, and the N-type doped region is covered with aluminum electrode material.

[0013] Furthermore, the terrace is a P-type circular ring connected to the P2 layer of the cathode, with a width of 3.5±0.1mm and a depth of 12±1µm.

[0014] Furthermore, the anode is P-type doped and its surface is covered with aluminum electrode material.

[0015] Furthermore, the first isolation trench isolates the central gate from the amplifying gate, and has a width of 0.5±0.01 mm and a depth of 7±1 µm.

[0016] Furthermore, the second isolation groove isolates the amplifying gate and its amplifying gate extension line segment, the amplifying gate extension branch and the cathode, and has a width of 0.7±0.01mm and a depth of 21±1µm.

[0017] The present invention has the following beneficial effects: 1. After designing this sunken mutation junction structure in the body of the electrically controlled thyristor, the excessively high forward voltage causes the space charge layer of the reverse bias junction to expand and punch through the sunken mutation junction, so that the transition starts in this area. The punch-through current is equivalent to the gate trigger current that has entered the amplifying gate region, causing the auxiliary thyristor to turn on, and quickly introduces the large anode current and high potential into the aluminum layer on the upper surface of the auxiliary thyristor, which is sufficient to strongly trigger the main thyristor and enter the safe mode of opening the amplifying gate-cathode perimeter, completing the self-protection function design of the device; by accurately designing the size of the sunken mutation junction, the size of the punch-through channel is accurately controlled, thereby determining the size of the punch-through short-circuit current, thereby determining the level of the transition voltage.

[0018] 2. The fundamental advantage of the protection function of the present invention is that the overvoltage self-protection function is integrated inside the device, without the need for complicated external circuit triggering protection, which greatly simplifies the thyristor application circuit and improves the reliability of the power electronic device.

[0019] 3. A large number of components and circuits such as thyristor assembly isolation detection protection trigger are omitted, which saves a lot of costs and improves the reliability of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a cross-sectional schematic diagram of an electrically controlled thyristor in the prior art; Figure 2 A schematic diagram of the expansion of the space charge layer of the prior art electrically controlled thyristor with a forward voltage applied; Figure 3 It is a schematic diagram of the gate triggering conduction of the electric-controlled thyristor in the prior art; Figure 4 It is a plan view schematic diagram of the thyristor of the present invention; Figure 5 for Figure 4 Section along C-C'; Figure 6 A schematic diagram of the thyristor of the present invention being turned on when a forward voltage is applied and the thyristor has a precise turning self-protection function.

[0021] Explanation of the accompanying reference numerals: central gate 1, amplifying gate 2, amplifying gate extension line segment 3a, amplifying gate extension branch 3b, cathode 4, table 5, anode 6, first isolation trench 7, second isolation trench 8, sudden junction 9. DETAILED DESCRIPTION

[0022] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] According to power semiconductor theory, a specific blocking voltage requires a specific resistivity silicon material and a PN junction of a certain depth in order to form a space charge layer of a specific width to withstand the blocking voltage.

[0024] Figure 1 It is a cross-sectional schematic diagram of an electrically controlled thyristor in the prior art, wherein: the four layers refer to the P1 layer, the N1 layer, the P2 layer, and the N2 layer; the three terminals refer to the anode terminal A, the cathode terminal K, and the gate terminal G; J1 is a reverse blocking PN junction; J2 is a forward blocking PN junction; J3 is a cathode emitter junction; k is an auxiliary amplifying gate; and L is an extended line segment of the amplifying gate.

[0025] like Figure 2 As shown, according to the principle of thyristor, it can be known that: when N-type semiconductor and P-type semiconductor are combined to form a PN junction. Due to the difference in the concentration of electrons and holes at the junction of N-region and P-region, the majority carriers (majority carriers) of each region diffuse to another region and become minority carriers (minority carriers) in the other region, leaving impurity ions with positive and negative charges but unable to move arbitrarily on both sides of the interface. These immovable positive and negative charges are called space charges, and the electric field established by the space charges is called the internal electric field or self-built electric field. Its direction is to prevent the diffusion movement of majority carriers, and on the other hand, it attracts minority carriers in the other region to move to this region, which is the so-called drift movement. Diffusion movement and drift movement are both interrelated and contradictory, and finally reach a dynamic balance, and the amount of positive and negative space charges reaches a stable value, forming a stable range of space charges, which is called the space charge region. When a forward voltage is applied to the thyristor, for J2, the direction of the external electric field is consistent with the self-built electric field, so the space charge region is widened here; for J1 junction, the direction of the external electric field is opposite to the self-built electric field, so the space charge region is shortened here. When the avalanche breakdown voltage is applied to the J2 junction, a turning conduction will occur in the weak area of ​​the J2 junction, causing a negative resistance effect and forming a strong short-circuit current I AK , burning out the thyristor.

[0026] Figure 3 Schematic diagram of gate triggering of an electrically controlled thyristor in the prior art. When a positive voltage is applied to the cathode K by the gate G through an external circuit, the polarity of the thyristor is positive at the bottom and negative at the top, because the P2N2 junction is in a forward biased state, which will force the gate current I g It flows horizontally into the lower end of the cathode and flows back to the negative electrode through the short-circuit point and cathode K, forming a closed loop. Due to the existence of the short base lateral resistance, the gate "current density" is the largest at N2 close to the gate and the smallest at a distance. As the gate voltage increases. Gate current I g When the positive bias voltage P2N2 junction opens, the N2 region near the gate reaches the open voltage first, which reduces the anode current IAK1 It leads to the strong triggering of the amplifier gate L, forming the normal triggering mode of the thyristor, causing the thyristor to be safely turned on.

[0027] The present invention discloses a self-protection electrically controlled thyristor with precise control of the transition voltage. The self-protection function is realized by designing a sunken mutation junction structure under the amplification gate. The size of the penetration channel is controlled by controlling the size and shape of the sunken mutation junction, thereby determining the size of the short-circuit current, thereby precisely controlling the transition voltage.

[0028] A sunken distorted ring mutation junction with appropriate width and depth is created in the forward blocking area below the auxiliary amplifier gate k of the original thyristor, so that the thickness of the long base region N1 at this location becomes narrower. When the forward voltage is too high, the space charge layer of the J2 junction at this location first penetrates the J1 junction to form a hole current injection channel, which is equivalent to the gate current I g Flowing from under the amplifier gate, causing N 21 The electrons are emitted, causing the auxiliary amplifier gate k to open, and the large current and high potential of the anode are quickly introduced into the extended line segment L of the amplifier gate, which strongly triggers the cathode surface of the thyristor, turns on the thyristor, and completes the safe conduction of the thyristor.

[0029] Figure 4 , Figure 5 is a schematic diagram of the present invention, wherein Figure 4 It is a top view; Figure 5 yes Figure 4 Cross-sectional view along C-C'. From the horizontal point of view, it is composed of a central gate 1, an amplifying gate 2, a cathode 4, a table 5 and an anode 6 on the back; the central gate 1 is located at the center of the device and is circular; the outer end of the central gate 1 is provided with an amplifying gate 2 in a circular ring shape; the amplifying gate 2 is provided with amplifying gate extension segments 3a along six directions, and a V-shaped amplifying gate extension branch 3b is connected to the end of each amplifying gate extension segment 3a, and the end is an arc shape; the amplifying gate extension segment 3a and the amplifying gate extension branch 3b extend deep into the cathode 4, and evenly separate the cathode 4 area; a first isolation groove 7 is provided between the central gate 1 and the amplifying gate 2; a second isolation groove 8 is provided between the amplifying gate 2 and its amplifying gate extension segment 3a and the amplifying gate extension branch 3b and the cathode 4; a circular table 5 is provided at the outermost end of the device, which is connected to the cathode 4. It is divided into a four-layer three-terminal structure in the longitudinal direction, and the four layers are N2 layer, P - +P2 layer, N1 layer, P1 layer; the three terminals refer to the anode A terminal, the cathode K terminal, and the gate G terminal; the device is symmetrical about the y axis.

[0030] Create a P with appropriate width and depth in the forward blocking region below the amplifier gate 2. - Layer sunken ring mutation knot 9, the P -The layer-depression blocking junction 9 is doped with aluminum ions, with a surface concentration of 1-2×10 21 Pieces / cm 3 , width is 2±0.1cm, depth is 20±5µm; the size of the mutation junction 9 accurately controls the size of the through channel, which in turn determines the size of the short-circuit current, thereby accurately controlling the turning voltage.

[0031] The N2 layer is doped with phosphorus at a concentration of 1-2×10 25 Pieces / cm 3 , with a depth of 25±2µm; the P1 layer and the P2 layer are doped with the same impurity aluminum element, with a concentration of 4-6×10 21 Pieces / cm 3 , depth is 95±5µm; N1 layer is zone melting high resistance silicon single crystal, resistivity is 500±7%Ω.cm; concentration is 1-2×10 19 Pieces / cm 3 , thickness is 1250±10µm, crystal orientation is <111> .

[0032] The central gate 1 is a P-shaped circle with a diameter of 4±0.01 mm and a surface covered with aluminum electrode material.

[0033] The amplifying gate 2 is composed of two circular rings, one of which is an N-type circular ring: the inner diameter is 3.5±0.01cm and the outer diameter is 4.5±0.01cm; the other is a P-type circular ring, the inner diameter is 4.5±0.01cm and the outer diameter is 5.5±0.01cm; the two circular rings are covered with aluminum electrode material.

[0034] The amplifying gate extension line segment 3a is composed of 6 P-type line segments, the width of which is 1.0mm±0.01mm near the amplifying gate 2 and is connected to the P-type circular ring of the amplifying gate 2; the portion away from the amplifying gate 2 is 0.3mm±0.01mm, and the width gradually decreases; and at the end of the amplifying gate extension line segment 3a, it is divided into a V-shaped amplifying gate extension branch 3b, the P-type doping width gradually decreases from 0.3mm±0.01mm to 0.2±0.01mm, and the end is an arc shape; the amplifying gate extension line segment 3a and the amplifying gate extension branch 3b are covered with aluminum electrode material and are connected to the aluminum electrode material of the amplifying gate 2.

[0035] The cathode 4 is an N-type doped region, on which P-type dots with a diameter of 0.1±0.01 mm are evenly distributed, and are connected to the P2 layer below the N-type doped region to form a P-type short-circuit channel. The cathode 4 is connected to the amplifying gate 2 and its amplifying gate extension line segment 3a and the outer end of the amplifying gate extension branch 3b, and the N-type doped region is covered with aluminum electrode material.

[0036] The table 5 is a P-type circular ring connected to the P2 layer of the cathode 4, with a width of 3.5±0.1mm and a depth of 12±1µm.

[0037] The anode 6 is P-type doped, and its surface is covered with aluminum electrode material.

[0038] The first isolation groove 7 isolates the central gate 1 from the amplifying gate 2 and has a width of 0.5±0.01 mm and a depth of 7±1 µm.

[0039] The second isolation groove 8 isolates the amplifying gate 2 and its amplifying gate extension line segment 3a, the amplifying gate extension branch 3b from the cathode 4, and has a width of 0.7±0.01mm and a depth of 21±1µm.

[0040] in Figure 6 for Figure 5 Schematic diagram of self-protection conduction when applying forward voltage. When the device is applied with forward voltage (i.e., the anode is applied with forward voltage and the cathode is applied with reverse voltage), the J2 junction is in reverse bias state. Due to the effect of the external electric field, the holes in the P2 region will diffuse to the N1 region, and the electrons in the N1 region will diffuse to the P2 region, forming a space charge layer. As the applied forward voltage increases, the space charge region also widens. Due to the existence of the mutation junction 9, it will first penetrate the forward bias junction J1 at the mutation junction 9, and the anode current I AK1 It leads to the triggering of the amplifying gate 2, forming the normal triggering mode of the thyristor, causing the thyristor to turn on. It can be seen that the self-protection function is integrated inside the chip. By precisely controlling the size and shape of the sunken mutation junction 9, the size of the through channel is precisely controlled, thereby determining the short-circuit current I AK1 The size of the resistor can be adjusted to accurately control the transition voltage.

[0041] The present invention only needs to add a photolithography process before the traditional thyristor doping process, and selective aluminum ion implantation and driving process form P - The doping area is sufficient, and the subsequent process is carried out according to the traditional thyristor process without any changes.

Claims

1. A self-protection electrically controlled thyristor with precise control of the breakover voltage, characterized in that: From a horizontal perspective, the device is composed of a central gate (1), an amplifying gate (2), an amplifying gate extension line segment (3a) and an amplifying gate extension branch (3b), a cathode (4), a table (5) and an anode (6) on the back. The central gate (1) is located in the center of the device and is circular. An amplifying gate (2) is provided at the outer end of the central gate (1) and is in a circular ring shape. The amplifying gate (2) is provided with amplifying gate extension line segments (3a) in six directions, and a V-shaped amplifying gate is connected to the end of each amplifying gate extension line segment (3a). The gate extension branch (3b) has an arc-shaped end; the gate extension line segment (3a) and the gate extension branch (3b) extend deep into the cathode (4) to evenly separate the cathode (4) area; a first isolation groove (7) is provided between the central gate (1) and the gate extension (2); a second isolation groove (8) is provided between the gate extension (2) and the gate extension line segment (3a) and the gate extension branch (3b) and the cathode (4); a circular ring-shaped table (5) is provided at the outermost end of the device and is connected to the cathode (4); From the vertical perspective, it is a four-layer three-terminal structure, with the four layers being N2, P - +P2 layer, N1 layer, P1 layer; the three terminals refer to the anode A terminal, the cathode K terminal, and the gate G terminal; the device is symmetrical about the y axis; A P is created in the forward blocking region below the amplifier gate (2). - Layer sunken ring mutation knot (9), the P - The layer-depressed circular ring abrupt junction (9) is doped with aluminum ions, with a surface concentration of 1-2×10 21 Pieces / cm 3 , width is 2±0.1cm, depth is 20±5µm; the size of the sunken circular abrupt junction (9) accurately controls the size of the through-channel, thereby determining the size of the short-circuit current, thereby accurately controlling the transition voltage.

2. A self-protection electrically controlled thyristor with precise control of transition voltage as claimed in claim 1, characterized in that: The N2 layer is doped with phosphorus at a concentration of 1-2×10 25 Pieces / cm 3 , with a depth of 25±2µm; the P1 layer and the P2 layer are doped with the same impurity aluminum element, with a concentration of 4-6×10 21 Pieces / cm 3 , depth is 95±5µm; N1 layer is zone melting high resistance silicon single crystal, resistivity is 500±7%Ω.cm; concentration is 1-2×10 19 Pieces / cm 3 , thickness is 1250±10µm, crystal orientation is <111> .

3. A self-protection electrically controlled thyristor with precise control of transition voltage as claimed in claim 1, characterized in that: The central gate (1) is a P-shaped circular shape with a diameter of 4±0.01 mm, and its surface is covered with aluminum electrode material.

4. A self-protection electrically controlled thyristor with precise control of transition voltage as claimed in claim 1, characterized in that: The amplifying gate (2) is composed of two circular rings, one of which is an N-type circular ring: the inner diameter is 3.5±0.01cm and the outer diameter is 4.5±0.01cm; the other is a P-type circular ring, the inner diameter is 4.5±0.01cm and the outer diameter is 5.5±0.01cm; the two circular rings are covered with aluminum electrode material.

5. A self-protection electrically controlled thyristor with precise control of transition voltage as claimed in claim 1, characterized in that: The amplifying gate extension line segment (3a) is composed of 6 P-type line segments, the width of which is 1.0 mm ± 0.01 mm near the amplifying gate (2) and is connected to the P-type circular ring of the amplifying gate (2); the width of which is 0.3 mm ± 0.01 mm at the portion away from the amplifying gate (2), and the width gradually decreases; and at the end of the amplifying gate extension line segment (3a), it is further divided into a V-shaped amplifying gate extension branch (3b), and the P-type doping width gradually decreases from 0.3 mm ± 0.01 mm to 0.2 ± 0.01 mm; the amplifying gate extension line segment (3a) and the amplifying gate extension branch (3b) are covered with aluminum electrode material and are connected to the aluminum electrode material of the amplifying gate (2).

6. A self-protection electrically controlled thyristor with precise control of transition voltage as claimed in claim 1, characterized in that: The cathode (4) is an N-type doped region, on which P-type dots with a diameter of 0.1±0.01 mm are evenly distributed, connected to the P2 layer below the N-type doped region to form a P-type short-circuit channel, the cathode (4) is connected to the amplifying gate (2) and its amplifying gate extension line segment (3a), and the outer end of the amplifying gate extension branch (3b), and the N-type doped region is covered with aluminum electrode material.

7. A self-protection electrically controlled thyristor with precise control of transition voltage as claimed in claim 1, characterized in that: The table (5) is a P-shaped circular ring connected to the P2 layer of the cathode K, with a width of 3.5±0.1 mm and a depth of 12±1 µm.

8. The self-protection electrically controlled thyristor with accurate control of the breakover voltage as claimed in claim 1, characterized in that: The first isolation groove (7) isolates the central gate (1) from the amplifying gate (2) and has a width of 0.5±0.01 mm and a depth of 7±1 µm.

9. A self-protection electrically controlled thyristor with precise control of transition voltage as claimed in claim 1, characterized in that: The second isolation groove (8) isolates the amplifying gate (2) and its amplifying gate extension line segment (3a), the amplifying gate extension branch (3b) from the cathode (4), and has a width of 0.7±0.01 mm and a depth of 21±1µm.

10. The self-protection electrically controlled thyristor with accurate control of the breakover voltage according to claim 1, characterized in that: The anode (6) is P-type doped, and its surface is covered with aluminum electrode material.

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