Single-mesa bidirectional TVS device

Abstract

The utility model discloses a bidirectional TVS device with a single table top, which comprises a substrate, a first doping layer arranged on the upper surface of the substrate, a second doping layer arranged on the lower surface of the substrate and two third doping layers arranged on the two edges of the substrate, a first PN junction is formed between the first doping layer and the substrate, a second PN junction is formed between the second doping layer and the substrate, and a third PN junction is formed between the second doping layer and the substrate. A first PN junction is formed between the first doping layer and the substrate, a second PN junction is formed between the second doping layer and the substrate, a third PN junction is formed between the third doping layer and the substrate, the edges of the two ends of the upper portion of the substrate are respectively provided with a groove, the upper surface of each groove is provided with a passivation layer, the two ends of the first PN junction are connected with the two grooves respectively, and the two ends of the second PN junction are connected with the two grooves through the two third PN junctions respectively. The circuit is of a PNP structure, can achieve a bidirectional protection function, and is stable and reliable in protection performance. According to the utility model, the bidirectional PN junction passivation protection of the single mesa structure can be realized, the breakdown voltages in two directions can be ensured to be consistent, and the performance and the stability of the product are further improved.

Description

Technical Field

[0001] The utility model relates to a semiconductor device, in particular to a single-table bidirectional TVS device. Background Art

[0002] A transient voltage suppressor (TVS) is an electronic component used to protect circuits. Its main function is to guide the excessive voltage to the ground line or power line when the transient voltage in the circuit is too high, so as to protect other components in the circuit from damage. Conventional TVS devices are usually unidirectional structures, and their protection capabilities are not stable enough, and there is a risk of leakage. Although the existing bidirectional TVS devices are more stable than unidirectional structures, they cannot achieve bidirectional PN junction passivation protection and also have the risk of leakage. Therefore, how to provide a TVS device with good protection capabilities and reliable performance has become an objective need. Utility Model Content

[0003] The utility model provides a single-table bidirectional TVS device, which is used to solve the problems of poor protection function and unstable performance of existing TVS devices.

[0004] To achieve the purpose of the utility model, the utility model provides a single-table bidirectional TVS device, which includes a substrate, a first doped layer arranged on the upper surface of the substrate, a second doped layer arranged on the lower surface of the substrate, and two third doped layers arranged on both edges of the substrate, a first PN junction is formed between the first doped layer and the substrate, a second PN junction is formed between the second doped layer and the substrate, and a third PN junction is formed between the third doped layer and the substrate, a groove is respectively provided at the two end edges of the upper part of the substrate, a passivation layer is provided on the upper surface of the groove, the two ends of the first PN junction are respectively connected to the two grooves, and the two ends of the second PN junction are respectively connected to the two grooves through the two third PN junctions.

[0005] The cross section of the groove is "U"-shaped, one side of which extends to the third doping layer, and the other side of which extends to the edge of the first doping layer. The groove depth of the groove is 60 to 80 microns.

[0006] The substrate is N-type <111> crystal direction, its thickness is 250 to 350 microns, and its resistivity is 0.002 to 3.0 Ω·cm.

[0007] Furthermore, the first doped layer is P-type doped, and a P-type fourth doped layer is provided between the substrate and the first doped layer. The length of the fourth doped layer along the horizontal direction is smaller than the length of the first doped layer along the horizontal direction. A fourth PN junction is formed between the fourth doped layer and the substrate, and both ends of the fourth PN junction are respectively connected to the first PN junction.

[0008] Further, the diffusion concentration of the fourth doping layer is greater than the diffusion concentration of the first doping layer, and the diffusion concentration of the first doping layer is greater than the diffusion concentration of the third doping layer.

[0009] Furthermore, the second doped layer is P-type doped, and a P-type fifth doped layer is provided between the substrate and the second doped layer. The length of the fifth doped layer along the horizontal direction is smaller than the length of the second doped layer along the horizontal direction. A fifth PN junction is formed between the fifth doped layer and the substrate, and both ends of the fifth PN junction are respectively connected to the second PN junction.

[0010] Furthermore, a diffusion concentration of the fifth doping layer is greater than a diffusion concentration of the second doping layer.

[0011] Furthermore, the third doping layer is P-type doped, and the third doping layer runs through from the upper end to the lower end of the substrate, and the lower part thereof is connected to the edge of the second doping layer.

[0012] The passivation layer includes a semi-insulating polysilicon film, a glass passivation film and a low-temperature oxidation film, the semi-insulating polysilicon film covers the inner wall of the groove, the glass passivation film covers the semi-insulating polysilicon film, and the low-temperature oxidation film covers the glass passivation film, a portion of the upper surface of the first doped layer and a portion of the upper surface of the third doped layer.

[0013] A first electrode is provided on the upper surface of the first doped layer, and a second electrode is provided on the lower surface of the second doped layer. The lower surface of the first electrode partially covers the upper surface of the first doped layer, and the upper surface of the second electrode covers the lower surface of the second doped layer and the lower surfaces of the two third doped layers.

[0014] The beneficial effects of the utility model are:

[0015] 1) By forming a first doping layer and a second doping layer on the upper surface and the lower surface of the substrate respectively, a PNP structure is formed, which can realize a bidirectional protection function, and the protection performance is stable and reliable.

[0016] 2) Grooves are set at both ends of the upper part of the substrate, and a third doping layer is set at the edges of both ends of the substrate. The third doping layer guides the second PN junction to the passivation layer in the groove. The passivation layer on the surface of the groove can realize the passivation protection of the first PN junction, the second PN junction and the third PN junction, which can realize the bidirectional PN junction passivation protection of the single-table structure, and also facilitate the subsequent die bonding production, reduce the stress between the TVS device and the lead frame during the die bonding process, and further improve the reliability of the product.

[0017] 3) A fourth doping layer is set between the first doping layer and the substrate, and a fifth doping layer is set between the second doping layer and the substrate. The breakdown voltage of the TVS device is controlled by the fourth PN junction and the fifth PN junction, so that the difference in breakdown voltage in two directions can be controlled within 1%, thereby ensuring that the breakdown voltage in two directions is consistent, further improving the performance and stability of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the utility model.

[0019] Figure 2 It is a production process flow chart of the utility model.

[0020] Figure 3 It is a structural schematic diagram of the manufacturing process step S10 of the utility model.

[0021] Figure 4 It is a structural schematic diagram of the manufacturing process step S20 of the present invention.

[0022] Figure 5 It is a structural schematic diagram of the manufacturing process step S30 of the present invention.

[0023] Figure 6 It is a structural schematic diagram of the manufacturing process step S40 of the utility model.

[0024] Figure 7 It is a structural schematic diagram of the manufacturing process step S50 of the utility model.

[0025] Figure 8 It is a structural schematic diagram of the manufacturing process step S60 of the present invention.

[0026] In the figure, 10, substrate, 20, first doped layer, 21, first PN junction, 30, second doped layer, 31, second PN junction, 40, third doped layer, 41, third PN junction, 50, trench, 60, passivation layer, 61, semi-insulating polysilicon film, 62, glass passivation film, 63, low-temperature oxide film, 70, fourth doped layer, 71, fourth PN junction, 80, fifth doped layer, 81, fifth PN junction, 91, first electrode, 92, second electrode. DETAILED DESCRIPTION

[0027] The technical solution of the utility model will be described clearly and completely below in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of them. Based on the embodiments of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0028] See also Figure 1 The utility model provides a single-table bidirectional TVS device, including a substrate 10, a first doping layer 20, a second doping layer 30, a third doping layer 40, a groove 50, a passivation layer 60, a first PN junction 21, a second PN junction 31 and a third PN junction. The substrate 10, the first doping layer 20 and the second doping layer 30 of the utility model form a PNP structure, which can realize a bidirectional protection function, and the protection performance is stable and reliable. The TVS device of the utility model can be used for various circuit protection components.

[0029] like Figure 1 As shown, the substrate 10 is of N-type <111> The crystal substrate single crystal has a thickness of 250-350 μm and a resistivity of 0.002-3.0 Ω·cm. A first doping layer 20 is provided on the upper surface of the substrate 10, and a second doping layer 30 is provided on the lower surface of the substrate 10. The first doping layer 20 partially covers the upper surface of the substrate 10, and the second doping layer 30 partially covers the lower surface of the substrate 10. Specifically, the first doping layer 20 is P-type doped, which is formed by boron diffusion, the diffusion temperature is 1260°C, the diffusion time is 15-25 hours, the diffusion sheet junction depth is 15-20 microns, and the square resistance R is 30-50Ω. The second doping layer 30 is P-type doped, which is formed by boron diffusion, the diffusion temperature is 1260°C, the diffusion time is 15-25 hours, the diffusion sheet junction depth is 15-20 microns, and the square resistance R is 30-50Ω. A PNP structure is formed between the first doping layer 20, the substrate 10 and the second doping layer 30. A first PN junction 21 is formed between the first doping layer 20 and the substrate 10, and a second PN junction 21 is formed between the second doping layer 30 and the substrate 10. By utilizing the reverse cutoff characteristics of the PN junction, the substrate 10 and the first doping layer 20 and the second doping layer 30 form a PNP structure, thereby realizing a bidirectional protection function.

[0030] like Figure 1 As shown, a third doping layer 40 is provided at both ends of the substrate 10, and the third doping layer 40 is P-type doped, and a third PN junction 41 is formed between the third doping layer 40 and the substrate 10. The third doping layer 30 penetrates from the upper end to the lower end of the substrate 10 to form a through channel, and its lower part is connected to the edge of the second doping layer 30, so that the second PN junction 31 is connected to the third PN junction 41. The third doping layer 30 is formed by boron diffusion or aluminum diffusion, wherein the diffusion temperature is 1275°C, the diffusion time is 140-170 hours, and the sheet resistance R is 200-300Ω.

[0031] like Figure 1As shown, two grooves 50 are provided on the upper part of the substrate 10, and the two grooves 50 are respectively provided at the two ends of the upper part of the substrate 10. Specifically, the cross section of the groove 50 is "U" shaped, and the groove depth is 60 to 80 microns. One end of the groove 50 extends to the edge of the first doping layer 20, and the other end extends to the third doping layer 40, so that the end of the first PN junction 21 and the end of the third PN junction 41 are respectively connected to the groove 50. At the same time, since the end of the second PN junction 31 is connected to the third PN junction 41, the third PN junction 41 can guide the end of the second PN junction 31 to the groove 50.

[0032] like Figure 1 As shown, a passivation layer 60 is provided on the upper surface of the groove 50, and the passivation layer 60 is used to provide high-reliability passivation protection for the first PN junction 21 and the third PN junction 41. The passivation layer 60 includes a semi-insulating polysilicon film 61, a glass passivation film 62 and a low-temperature oxide film 63. Among them, the semi-insulating polysilicon film 61 covers the inner wall of the groove 50, and its film thickness is 0.4-0.6 microns. The semi-insulating polysilicon film 61 can not only reduce the high-temperature leakage of the first PN junction 21 and the third PN junction 41, but also reduce the stress of the glass material on the substrate 10, thereby reducing the risk of cracking of the substrate 10. The glass passivation film 62 covers the semi-insulating polysilicon film 61, and the negative ion center in the glass passivation film 62 can effectively capture metal ions to avoid the contamination of the first PN junction 21 and the third PN junction 41 by metal ions, thereby reducing leakage and making the high-temperature performance of the TVS device more stable. The low temperature oxidation film 63 covers the upper surface of the glass passivation film 62, the upper surface of part of the first doping layer 20 and the upper surface of part of the third doping layer 40, and the film thickness is 4000±2000A. The low temperature oxidation film 63 can effectively avoid the effect of thermal expansion and contraction on the glass when the solder solidifies during the welding process. In this embodiment, since the first PN junction 21 is connected to the groove 50, and the second PN junction 31 is connected to the third PN junction 41, the edge terminal structure of the second PN junction 31 is connected to the groove 50, and the passivation protection of the first PN junction 21, the second PN junction 31 and the third PN junction 41 can be achieved through the passivation layer 60 on the surface of the groove 50, thereby realizing the bidirectional PN junction passivation protection of the single-table structure, facilitating the subsequent solid crystal production, reducing the stress between the TVS device and the lead frame during the solid crystal process, and further improving the reliability of the product.

[0033] In some embodiments, Figure 1As shown, a fourth doping layer 70 is provided between the substrate 10 and the first doping layer 20. The fourth doping layer 70 is P-type doped, and its length along the horizontal direction is less than the length of the first doping layer 20 along the horizontal direction. A fourth PN junction 71 is formed between the fourth doping layer 70 and the substrate 10, and the two ends of the fourth PN junction 71 are respectively connected to the first PN junction 21, which can control the breakdown voltage of the TVS device. The fourth doping layer 70 is formed by P-type ion implantation, and the implantation conditions are: the dosage 1e 15 ~1e 16 cm -2 , energy 80-100KeV, push junction conditions: temperature 1200-1215°C, time 100-180min, N2 flow 2-3L / min, O2 flow 2-3L / min. In this embodiment, the diffusion concentration of the fourth doping layer 70> the diffusion concentration of the first doping layer 20> the diffusion concentration of the third doping layer 40, then the breakdown voltage of the fourth PN junction 71 < the breakdown voltage of the first PN junction 21 < the breakdown voltage of the third PN junction 41, therefore, the breakdown voltage of the TVS device is determined by the breakdown voltage of the fourth PN junction 71.

[0034] like Figure 1 As shown, a fifth doping layer 80 is provided between the substrate 10 and the second doping layer 30. The fifth doping layer 80 is P-type doped, and its length along the horizontal direction is less than the length of the second doping layer 30 along the horizontal direction. A fifth PN junction 81 is formed between the fifth doping layer 80 and the substrate 10. The two ends of the fifth PN junction 81 are respectively connected to the second PN junction 31, which can control the breakdown voltage of the TVS device. The fifth doping layer 80 is formed by P-type ion implantation, and the implantation conditions are: the doping amount 1e 15 ~1e 16 cm -2 , energy 80~100KeV, the push junction conditions are: temperature 1200~1215℃, time 100~180min, N2 flow 2~3L / min, O2 flow 2~3L / min. In this embodiment, the diffusion concentration of the fifth doping layer 80 is greater than the diffusion concentration of the second doping layer 30, then the breakdown voltage of the fifth PN junction 81 is less than the breakdown voltage of the second PN junction 31, therefore, the breakdown voltage of the TVS device is determined by the breakdown voltage of the fifth PN junction 81. By controlling the breakdown voltage of the fourth PN junction 71 and the fifth PN junction 81, the difference in the breakdown voltage in the two directions can be controlled within 1%, thereby ensuring that the breakdown voltage in the two directions is consistent, further improving the performance and stability of the product.

[0035] like Figure 1As shown, a first electrode 91 is provided on the upper surface of the first doping layer 20, and a second electrode 92 is provided on the lower surface of the second doping layer 30. The first electrode 91 and the second electrode 92 are both metal electrodes, and the first electrode 91 and the second electrode 92 can be formed by covering the first doping layer 20 and the second doping layer 30 with a layer of metal titanium nickel silver, tin copper alloy or nickel gold alloy respectively by PVD, electroplating or chemical plating. In this embodiment, the first electrode 91 partially covers the upper surface of the first doping layer 20, and the second electrode 92 covers the lower surface of the second doping layer 30 and the lower surfaces of the two third doping layers 40. In some embodiments, before making the first electrode 91, a lead hole can be formed by photoresist, and the low temperature oxide film 63 remaining in the lead hole can be removed by wet etching.

[0036] like Figure 2 As shown, the manufacturing process of the single-table bidirectional TVS device of this embodiment includes:

[0037] S10, providing a substrate.

[0038] like Figure 2 As shown, in this step, the substrate 10 is N-type <111> The crystal substrate single crystal has a thickness of 250-350 μm and a resistivity of 0.002-3.0 Ω·cm. Specifically, a dense oxide layer of 1.6-2.0 μm is generated by hydrogen-oxygen synthesis, wherein the hydrogen-oxygen synthesis temperature is 1100°C, the hydrogen-oxygen synthesis time is 14 hours, the hydrogen flow rate is 7.0 L / min, and the oxygen flow rate is 5.0 L / min.

[0039] S20, preparing a third doping layer.

[0040] like Figure 4 As shown, in this step, windows of the third doping layer 40 are opened at both ends of the substrate 10 by photolithography and wet etching, and then a P-type third doping layer 40 is formed by boron diffusion or aluminum diffusion, the diffusion temperature is 1275°C, the diffusion time is 140 to 170 hours, and the square resistance R is 200 to 300Ω, wherein the third doping region 40 penetrates the substrate 10 to form a through channel.

[0041] S30, preparing a fourth doping layer and a fifth doping layer.

[0042] like Figure 5 As shown, in this step, by photolithography and wet etching, windows of the fourth doping layer 70 and the fifth doping layer 80 are opened on the upper surface and the lower surface of the substrate 10, respectively, and then by P-type ion implantation, the fourth doping layer 70 and the fifth doping layer 80 are formed, wherein the implantation conditions are: the dosage 1e 15 ~1e 16 cm -2, energy 80~100KeV, pushing conditions are: temperature 1200~1215℃, time 100~180min, N2 flow rate 2~3L / min, O2 flow rate 2~3L / min.

[0043] S40, preparing a first doping layer and a second doping layer.

[0044] like Figure 6 As shown, in this step, a first doping layer 20 is formed on the upper surface of the substrate 10 and the upper surface of the fourth doping layer 70 by boron diffusion, and a second doping layer 30 is formed on the lower surface of the substrate 10 and the lower surface of the fifth doping layer 80. The diffusion temperature is 1260°C, the diffusion time is 15 to 25 hours, the diffusion sheet junction depth is 15 to 20 microns, and the sheet resistance R is 30 to 50Ω.

[0045] S50: preparing grooves.

[0046] like Figure 7 As shown, in this step, a groove 50 is formed at both ends of the upper edge of the substrate 10. Specifically, a negative photoresist is used, the etching solution is kept at -5°C, and the etching is performed for 8 to 15 minutes to form a groove 50 with a depth of 60 to 80 um. The composition of the etching solution is: hydrofluoric acid: glacial acetic acid: nitric acid: sulfuric acid = 9:9:12:4.

[0047] S60, preparing a passivation layer.

[0048] like Figure 8 As shown, in this step, a passivation layer 60 is prepared on the upper surface of the groove 50, wherein the passivation layer 60 includes a semi-insulating polycrystalline silicon film 61, a glass passivation film 62 and a low-temperature oxide film 63. Specifically, the semi-insulating polycrystalline silicon scale 61 is formed by low-pressure chemical vapor deposition, wherein the reaction source gas is silane: nitrous oxide = 5:1, the deposition time is 30-50 minutes, and the film thickness of the semi-insulating polycrystalline silicon film 61 is 0.4-0.6um. The glass passivation film 62 is formed by glass passivation and sintering through a knife-scraping glass process, and its main component is glass paste, the glass powder model in the glass paste is GP200S or GP200 / W020, and the glass paste ratio is: butyl carbitol: ethyl cellulose: glass powder = 1: 0.05: 1.25, the glass sintering temperature is 820 ± 10 ° C, the sintering time is 15-25 minutes, and the sintering process is fully protected by oxygen. The low-temperature oxide film 63 is formed by low-pressure chemical vapor deposition. The reaction temperature is 450±50° C., the reaction time is 20-40 minutes, the reaction source gas is silane: oxygen in a ratio of 2:1, and the film thickness of the low-temperature oxide film 63 is 4000±2000A.

[0049] S70, preparing a first electrode and a second electrode.

[0050] like Figure 1As shown, in this step, a lead hole is formed by using photoresist, and the low temperature oxide film 63 remaining in the lead hole is removed by wet etching, and finally a layer of metal titanium nickel silver, tin copper alloy or nickel gold alloy is respectively covered on the upper surface of the first doping layer 20 and the lower surface of the second doping layer 30 by PVD, electroplating or chemical plating to form a first electrode 91 and a second electrode 92. Among them, the first electrode 91 partially covers the upper surface of the first doping layer 20, and the second electrode 92 covers the lower surface of the second doping layer 30 and the lower surfaces of the two third doping layers 40.

[0051] In summary, the single-table bidirectional TVS device of the present invention forms a PNP structure by respectively providing the first doping layer 20 and the second doping layer 30 on both sides of the substrate 10, thereby achieving bidirectional protection with stable and reliable protection performance.

[0052] On the other hand, a groove 50 is set at the edge of the substrate 10, and a third doping layer 40 is set at the two end edges of the substrate 10, wherein the first PN junction 21 and the third PN junction 41 are respectively connected to the groove 50, and the second PN junction 31 is connected to the third PN junction 41, so that the second PN junction 31 is connected to the groove 50 through the third PN junction 41, and the passivation layer 60 on the surface of the groove 50 can realize passivation protection of the first PN junction 21, the second PN junction 31 and the third PN junction 41, which can realize bidirectional PN junction passivation protection of the single-table structure, and is also convenient for subsequent die bonding production, reducing the stress between the TVS device and the lead frame during the die bonding process, and further improving the reliability of the product.

[0053] In addition, a fourth doping layer 70 is arranged between the substrate 10 and the first doping layer 20, and a fifth doping layer 80 is arranged between the substrate 10 and the second doping layer 30. By controlling the breakdown voltage of the fourth PN junction 71 and the fifth PN junction 81, the difference in the breakdown voltage in the two directions can be controlled within 1%, thereby ensuring that the breakdown voltage in the two directions is consistent, further improving the performance and stability of the product.

[0054] Although the present invention is disclosed through the above embodiments, the protection scope of the present invention is not limited thereto. Without departing from the concept of the present invention, any deformation, replacement, etc. made to the above components shall fall within the scope of the claims of the present invention.

Claims

1. A single-table bidirectional TVS device, characterized in that: The device includes a substrate, a first doping layer arranged on the upper surface of the substrate, a second doping layer arranged on the lower surface of the substrate, and two third doping layers arranged on the two edges of the substrate, a first PN junction is formed between the first doping layer and the substrate, a second PN junction is formed between the second doping layer and the substrate, and a third PN junction is formed between the third doping layer and the substrate. A groove is respectively provided at the two end edges of the upper part of the substrate, and a passivation layer is provided on the upper surface of the groove. The two ends of the first PN junction are respectively connected to the two grooves, and the two ends of the second PN junction are respectively connected to the two grooves through the two third PN junctions.

2. The single-table bidirectional TVS device according to claim 1, characterized in that: The cross section of the groove is "U"-shaped, one side of which extends to the third doping layer, and the other side of which extends to the edge of the first doping layer. The groove depth of the groove is 60 to 80 microns.

3. The single-table bidirectional TVS device according to claim 1, characterized in that: The substrate is N-type <111> crystal direction, its thickness is 250 to 350 microns, and its resistivity is 0.002 to 3.0 Ω·cm.

4. The single-table bidirectional TVS device according to claim 3, characterized in that: The first doped layer is P-type doped, and a P-type fourth doped layer is provided between the substrate and the first doped layer. The length of the fourth doped layer along the horizontal direction is smaller than the length of the first doped layer along the horizontal direction. A fourth PN junction is formed between the fourth doped layer and the substrate, and both ends of the fourth PN junction are respectively connected to the first PN junction.

5. The single-table bidirectional TVS device according to claim 4, characterized in that: The diffusion concentration of the fourth doping layer is greater than the diffusion concentration of the first doping layer, and the diffusion concentration of the first doping layer is greater than the diffusion concentration of the third doping layer.

6. The single-table bidirectional TVS device according to claim 3, characterized in that: The second doped layer is P-type doped, and a P-type fifth doped layer is provided between the substrate and the second doped layer. The length of the fifth doped layer along the horizontal direction is smaller than the length of the second doped layer along the horizontal direction. A fifth PN junction is formed between the fifth doped layer and the substrate, and both ends of the fifth PN junction are respectively connected to the second PN junction.

7. The single-table bidirectional TVS device according to claim 6, characterized in that: The diffusion concentration of the fifth doping layer is greater than the diffusion concentration of the second doping layer.

8. The single-table bidirectional TVS device according to claim 3, characterized in that: The third doping layer is P-type doped, and the third doping layer runs through from the upper end to the lower end of the substrate, and the lower part of the third doping layer is connected to the edge of the second doping layer.

9. The single-table bidirectional TVS device according to claim 1, characterized in that: The passivation layer includes a semi-insulating polysilicon film, a glass passivation film and a low-temperature oxidation film, the semi-insulating polysilicon film covers the inner wall of the groove, the glass passivation film covers the semi-insulating polysilicon film, and the low-temperature oxidation film covers the glass passivation film, a portion of the upper surface of the first doped layer and a portion of the upper surface of the third doped layer.

10. The single-table bidirectional TVS device according to claim 1, characterized in that: A first electrode is provided on the upper surface of the first doped layer, and a second electrode is provided on the lower surface of the second doped layer. The lower surface of the first electrode partially covers the upper surface of the first doped layer, and the upper surface of the second electrode covers the lower surface of the second doped layer and the lower surfaces of the two third doped layers.

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