A transient diode

Abstract

The application discloses a kind of transient diodes. Including: device main body;The device main body includes: at least one first bidirectional semiconductor chip, at least one second bidirectional semiconductor chip and conductive layer;The conductive layer is arranged between the first bidirectional semiconductor chip and the second bidirectional semiconductor chip, so that the first bidirectional semiconductor chip and the second bidirectional semiconductor chip are connected in series;Wherein, the first bidirectional semiconductor chip is N-type substrate bidirectional semiconductor chip, and the second bidirectional semiconductor chip is P-type substrate bidirectional semiconductor chip.The application provides a kind of transient diodes, realize to reduce transient diode residual voltage, improve the protection ability of device.

Description

Technical Field

[0001] This invention relates to the field of protection diode technology, and more particularly to a transient diode. Background Technology

[0002] A transient voltage suppressor (TVS) is a new product developed based on the Zener diode technology. When the two ends of a TVS diode are subjected to a sudden high-energy impact, it can reduce its impedance rapidly and absorb a large current, thereby fixing the voltage between its two ends at a predetermined value, thus ensuring that the downstream circuit components are protected from damage caused by the transient high-energy impact.

[0003] TVS diodes are widely used in computer systems, communication equipment, consumer electronics, power supplies, and home appliances due to their advantages such as fast response time, high transient power, low capacitance, low leakage current, small breakdown voltage deviation, easy control of pad voltage, small size, and easy installation. However, existing TVS devices have a residual voltage defect; excessive residual voltage can affect the protective effect of the device, thus reducing its reliability. Summary of the Invention

[0004] This invention provides a transient diode that reduces residual voltage and improves the protection capability of the device.

[0005] This invention provides a transient diode, comprising: a device body; the device body includes: at least one first bidirectional semiconductor chip, at least one second bidirectional semiconductor chip, and a conductive layer;

[0006] A conductive layer is disposed between the first bidirectional semiconductor chip and the second bidirectional semiconductor chip, so that the first bidirectional semiconductor chip and the second bidirectional semiconductor chip are connected in series; wherein, the first bidirectional semiconductor chip is a bidirectional semiconductor chip with an N-type substrate, and the second bidirectional semiconductor chip is a bidirectional semiconductor chip with a P-type substrate.

[0007] Optionally, the bidirectional semiconductor chip of the N-type substrate includes: an N-type substrate, a first P-type doped layer, and a second P-type doped layer;

[0008] The first P-type doped layer, the N-type substrate, and the second P-type doped layer are stacked sequentially; the first P-type doped layer or the second P-type doped layer is connected to the conductive layer.

[0009] Optionally, a first P-type doped layer is formed by doping P-type semiconductor ions under the first surface of the N-type substrate; a second P-type doped layer is formed by doping P-type semiconductor ions under the second surface of the N-type substrate; wherein the first surface and the second surface are opposite surfaces; the area of ​​the first P-type doped layer projected perpendicularly onto the first surface is smaller than the area of ​​the first surface, and the area of ​​the second P-type doped layer projected perpendicularly onto the second surface is smaller than the area of ​​the second surface.

[0010] Optionally, the first P-type doped layer and the second P-type doped layer are centrally symmetrical about the N-type substrate.

[0011] Optionally, the bidirectional semiconductor chip of the P-type substrate includes: a P-type substrate, a first N-type doped layer, and a second N-type doped layer; the first N-type doped layer, the P-type substrate, and the second N-type doped layer are stacked sequentially; the first N-type doped layer or the second N-type doped layer is connected to the conductive layer.

[0012] Optionally, a first N-type doped layer is formed by doping N-type semiconductor ions under the first surface of the P-type substrate; a second N-type doped layer is formed by doping N-type semiconductor ions under the second surface of the P-type substrate; wherein the first surface and the second surface are opposite surfaces; the area of ​​the first N-type doped layer projected perpendicularly onto the first surface is smaller than the area of ​​the first surface, and the area of ​​the second N-type doped layer projected perpendicularly onto the second surface is smaller than the area of ​​the second surface.

[0013] Optionally, the first N-type doped layer and the second N-type doped layer are centrally symmetrical about the P-type substrate.

[0014] Optionally, the transient diode further includes an encapsulation layer;

[0015] The encapsulation layer covers the surface of the device body.

[0016] Optionally, the encapsulation layer includes at least one of silicone resin and epoxy resin.

[0017] Optionally, the conductive layer includes a conductive adhesive.

[0018] The technical solution of this invention, by encapsulating bidirectional semiconductor chips with different substrates in series to form a transient diode, increases the maximum voltage that the transient diode can withstand. Under a given current carrying capacity, this further increases the maximum peak pulse dissipation power that the transient diode can withstand. Based on the lower residual voltage of the P-type substrate bidirectional semiconductor chip in the middle stage of the current response, the residual voltage in the middle stage of the series connection of two different substrates is lowered. Similarly, based on the lower residual voltage of the N-type substrate bidirectional semiconductor chip in the early stage of the current response, the residual voltage in the early stage of the series connection of two different substrates is lowered. By connecting bidirectional semiconductor chips with different substrates in series based on the residual voltage characteristics of different substrates, the residual voltage of the protection device is reduced, compensating for the residual voltage defects of a single-chip series structure, improving the protection capability of the transient diode. Furthermore, in actual production, this can be implemented on the existing basis, reducing modification costs and improving product competitiveness. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a transient diode provided in an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram of the residual voltage of two bidirectional semiconductor chips connected in series on a P-type substrate.

[0021] Figure 3 This is a schematic diagram of the residual voltage of two bidirectional semiconductor chips connected in series on an N-type substrate.

[0022] Figure 4 This is a schematic diagram of the residual voltage of a bidirectional semiconductor chip on an N-type substrate and a bidirectional semiconductor chip on a P-type substrate connected in series.

[0023] Figure 5 This is a schematic diagram of another transient diode provided in an embodiment of the present invention.

[0024] Figure 6 This is a schematic diagram of another transient diode provided in an embodiment of the present invention.

[0025] Figure 7 This is a schematic diagram of another transient diode provided in an embodiment of the present invention.

[0026] Figure 8 This is a schematic diagram of another transient diode provided in an embodiment of the present invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Figure 1 A schematic diagram of a transient diode provided in an embodiment of the present invention is shown below. Figure 1 The device body 140 includes at least one first bidirectional semiconductor chip 110, at least one second bidirectional semiconductor chip 120, and a conductive layer 130.

[0029] A conductive layer 130 is disposed between the first bidirectional semiconductor chip 110 and the second bidirectional semiconductor chip 120, so that the first bidirectional semiconductor chip 110 and the second bidirectional semiconductor chip 120 are connected in series; wherein, the first bidirectional semiconductor chip 110 is a bidirectional semiconductor chip with an N-type substrate, and the second bidirectional semiconductor chip 120 is a bidirectional semiconductor chip with a P-type substrate.

[0030] Specifically, transient diodes include unidirectional transient diodes and bidirectional transient diodes. The forward characteristics of a unidirectional transient diode are the same as those of a typical Zener diode, while its reverse breakdown inflection point is approximately "right-angled," indicating hard breakdown; it is a typical PN junction avalanche device. When a transient overvoltage pulse occurs, the device current increases sharply, while the reverse voltage rises to the clamping voltage and remains at that level. The characteristic curve of a bidirectional transient diode is like two unidirectional transient diodes combined "back-to-back." It has the same avalanche breakdown and clamping characteristics in both forward and reverse directions. Once the interference voltage applied across it exceeds the clamping voltage, it will be immediately suppressed. Bidirectional transient diodes are very convenient for AC circuit applications. Bidirectional transient diodes are packaged using bidirectional semiconductor chips connected in series. A bidirectional semiconductor refers to a semiconductor comprising two parallel PN junctions, enabling bidirectional triggering. The first bidirectional semiconductor chip 110 and the second bidirectional semiconductor chip 120 have different substrates. The first bidirectional semiconductor chip 110 can be a bidirectional semiconductor chip with an N-type substrate, and the second bidirectional semiconductor chip 120 can be a bidirectional semiconductor chip with a P-type substrate.

[0031] When there are multiple first bidirectional semiconductor chips 110 and second bidirectional semiconductor chips 120, the first bidirectional semiconductor chips 110 and second bidirectional semiconductor chips 120 are connected in series at intervals. This is an exemplary embodiment of the present invention. Figure 1The device employs a first bidirectional semiconductor chip 110 and a second bidirectional semiconductor chip 120 connected in series. By connecting the bidirectional semiconductor chips in series, the maximum voltage that the device can withstand is increased, thereby increasing the maximum peak pulse dissipation power that the transient diode can withstand. Figure 2 A schematic diagram of the residual voltage of two bidirectional semiconductor chips connected in series on a P-type substrate, see [link / reference]. Figure 2 Residual voltage refers to the clamping voltage under a specific current during a surge. During the current increase, the residual voltage measured in the series connection of two bidirectional semiconductor chips on a P-type substrate exhibits a higher peak value in the early stages of the current response. This higher peak value may exceed the safe voltage of the protection device, thus affecting its protection performance. Figure 3 A schematic diagram of the residual voltage of two bidirectional semiconductor chips connected in series on an N-type substrate, see [link / reference]. Figure 3 During the current increase process, the residual voltage measured in the middle stage of the current response of the two bidirectional semiconductor chips connected in series on the N-type substrate is relatively high. Figure 4 A schematic diagram of the residual voltage of a bidirectional semiconductor chip on an N-type substrate and a bidirectional semiconductor chip on a P-type substrate connected in series. See [link / reference]. Figure 4 By connecting bidirectional semiconductors with two different substrates in series, the residual voltage of the connected bidirectional semiconductor chips is lowered in the middle stage of the current response, based on the lower residual voltage of the P-type substrate bidirectional semiconductor chip. Similarly, the residual voltage of the connected bidirectional semiconductor chips with an N-type substrate bidirectional semiconductor chip is lowered in the early stage of the current response. Connecting bidirectional semiconductor chips with different substrates based on their residual voltage characteristics reduces the residual voltage of transient diodes, improving protection capabilities. Furthermore, in actual production, this can be implemented on the existing basis, reducing upgrade costs and enhancing product competitiveness.

[0032] The technical solution of this invention, by encapsulating bidirectional semiconductor chips with different substrates in series to form a transient diode, increases the maximum voltage that the transient diode can withstand. Under a given current carrying capacity, this further increases the maximum peak pulse dissipation power that the transient diode can withstand. Based on the lower residual voltage of the P-type substrate bidirectional semiconductor chip in the middle stage of the current response, the residual voltage in the middle stage of the series connection of two different substrates is lowered. Similarly, based on the lower residual voltage of the N-type substrate bidirectional semiconductor chip in the early stage of the current response, the residual voltage in the early stage of the series connection of two different substrates is lowered. By connecting bidirectional semiconductor chips with different substrates in series based on the residual voltage characteristics of different substrates, the residual voltage of the protection device is reduced, compensating for the residual voltage defects of a single-chip series structure, improving the protection capability of the transient diode. Furthermore, in actual production, this can be implemented on the existing basis, reducing modification costs and improving product competitiveness.

[0033] Optionally, the bidirectional semiconductor chip with an N-type substrate includes: an N-type substrate, a first P-type doped layer, and a second P-type doped layer; the first P-type doped layer, the N-type substrate, and the second P-type doped layer are stacked sequentially; the first P-type doped layer or the second P-type doped layer is connected to a conductive layer.

[0034] Specifically, Figure 5 A schematic diagram of another transient diode provided in an embodiment of the present invention is shown below. Figure 5 The first bidirectional semiconductor chip 110 is a bidirectional semiconductor core on an N-type substrate, with the N-type substrate 111 as the main body. For example, the N-type substrate 111 can be block-shaped. A first P-type doped layer 112 and a second P-type doped layer 113 are doped and diffused on the top and bottom sides of the N-type substrate 111. The bidirectional semiconductor chip on the N-type substrate 111 is connected in series with the bidirectional semiconductor core on the P-type substrate through a conductive layer 130. That is, any P-type doped layer of the bidirectional semiconductor core on the N-type substrate 111 is connected to the bidirectional semiconductor core on the P-type substrate through the conductive layer 130. It should be noted that the connection relationships in the figure include direct contact connections, and may also include indirect connection structures such as passivation layers and electrode layers, without limitation. The hierarchical structure can increase the contact area between the N-type substrate and the P-type doped layer, thereby increasing the current carrying capacity of the semiconductor.

[0035] Figure 6 A schematic diagram of another transient diode provided in an embodiment of the present invention is shown below. Figure 6 A first P-type doped layer 112 is formed by doping P-type semiconductor ions under the first surface of the N-type substrate 111; a second P-type doped layer 113 is formed by doping P-type semiconductor ions under the second surface of the N-type substrate 111; wherein the first surface and the second surface are opposite surfaces; the area of ​​the first P-type doped layer 112 projected vertically onto the first surface is smaller than the area of ​​the first surface, and the area of ​​the second P-type doped layer 113 projected vertically onto the second surface is smaller than the area of ​​the second surface.

[0036] Specifically, P-type ions are diffused onto the opposing surfaces of the N-type substrate 111 to form a first P-type doped layer 112 and a second P-type doped layer 113, forming a trench-like layered structure. The resulting layered structure consists of the first P-type doped layer 112, the N-type substrate 111, and the second P-type doped layer 113 stacked sequentially. The projected areas of the first P-type doped layer 112 and the second P-type doped layer 113 on their respective surfaces are smaller than their respective surface areas. The first P-type doped layer 112 and the second P-type doped layer 113 are embedded within the N-type substrate 111, reducing the stacking of layers and thus reducing the thickness and size of the transient diode.

[0037] Optionally, the first P-type doped layer and the second P-type doped layer are centrally symmetrical about the N-type substrate.

[0038] Specifically, the first P-type doped layer and the second P-type doped layer are disposed opposite each other on both sides of the N-type substrate, that is, the vertical projection of the first P-type doped layer on the N-type substrate and the vertical projection of the second P-type doped layer on the N-type substrate coincide, thereby improving the current carrying capacity of the bidirectional transient diode.

[0039] See also Figure 5 The bidirectional semiconductor chip with a P-type substrate includes: a P-type substrate 121, a first N-type doped layer 122, and a second N-type doped layer 123; the first N-type doped layer 122, the P-type substrate 121, and the second N-type doped layer 123 are stacked sequentially; the first N-type doped layer 122 or the second N-type doped layer 123 is connected to the conductive layer 130.

[0040] Specifically, the second bidirectional semiconductor chip 120 is a bidirectional semiconductor core on a P-type substrate, with the P-type substrate 121 as the main body. A first N-type doped layer 122 and a second N-type doped layer 123 are disposed on the upper and lower sides of the P-type substrate 121. For example, the P-type substrate 121 can be block-shaped. The first N-type doped layer 122 and the second N-type doped layer 123 are disposed on the upper and lower sides of the P-type substrate 121. The bidirectional semiconductor chip on the P-type substrate is connected in series with the bidirectional semiconductor core on the N-type substrate through a conductive layer 130. That is, any N-type doped layer of the bidirectional semiconductor core on the P-type substrate is connected to the bidirectional semiconductor core on the N-type substrate through the conductive layer 130. It should be noted that the connection relationship in the figure includes direct contact connection, and may also include indirect connection structures such as passivation layers and electrode layers, without limitation. The hierarchical structure can increase the contact area between the P-type substrate and the N-type doped layer, thereby increasing the current carrying capacity of the semiconductor.

[0041] See also Figure 6 Optionally, a first N-type doped layer 122 is formed by doping N-type semiconductor ions under the first surface of the P-type substrate 121; a second N-type doped layer 123 is formed by doping N-type semiconductor ions under the second surface of the P-type substrate 121; wherein the first surface and the second surface are opposite surfaces; the area of ​​the first N-type doped layer 122 projected vertically onto the first surface is smaller than the area of ​​the first surface, and the area of ​​the second N-type doped layer 123 projected vertically onto the second surface is smaller than the area of ​​the second surface.

[0042] Specifically, N-type ions are diffused onto the opposite surfaces of the P-type substrate 121 to form a first N-type doped layer 122 and a second N-type doped layer 123, forming a trench-like layered structure. The resulting layered structure consists of the first N-type doped layer 122, the P-type substrate 121, and the second N-type doped layer 123 stacked sequentially. The projected areas of the first N-type doped layer 122 and the second N-type doped layer 123 on their respective surfaces are smaller than their respective surface areas. The first N-type doped layer 122 and the second N-type doped layer 123 are embedded within the P-type substrate 121, reducing the stacking of layers and thus reducing the thickness and size of the transient diode.

[0043] Optionally, the first N-type doped layer 122 and the second N-type doped layer 123 are centrally symmetrical about the P-type substrate.

[0044] Specifically, the first N-type doped layer 122 and the second N-type doped layer 123 are disposed opposite to each other on both sides of the P-type substrate, that is, the vertical projection of the first N-type doped layer on the P-type substrate and the vertical projection of the second N-type doped layer on the P-type substrate coincide, thereby improving the current carrying capacity of the bidirectional transient diode.

[0045] Figure 7 This is a schematic diagram of another transient diode provided in an embodiment of the present invention. Figure 8 A schematic diagram of another transient diode provided in an embodiment of the present invention is shown below. Figure 7 and Figure 8 The transient diode also includes a packaging layer 410; the packaging layer 410 covers the surface of the device body to form a packaged device body.

[0046] Specifically, device electrode leads 420 are provided at both ends of the device body, and the device body is covered with a packaging layer 410. The packaging layer 410 serves as a protective layer to protect bidirectional semiconductor chips with different substrates, forming a stable structure and preventing gas molecules from being ionized and generating excess charge under high temperature and high pressure, which would affect the protection stability of the transient diode.

[0047] Optionally, the encapsulation layer may include at least one of silicone resin and epoxy resin.

[0048] Optionally, the conductive layer includes conductive adhesive. Specifically, the conductive layer can be applied between bidirectional semiconductor chips using methods such as spraying, photolithography, inkjet printing, and screen printing to form a series electrical connection structure. The conductive layer includes conductive adhesive, which is an adhesive that exhibits a certain degree of conductivity after curing or drying. It can connect multiple conductive materials together, creating an electrical path between the connected materials. In the electronics industry, conductive adhesive has become an indispensable new material. There are many types of conductive adhesives, which can be divided into general conductive adhesives and special conductive adhesives from an application perspective. General conductive adhesives only have certain requirements for conductivity and bonding strength, while special conductive adhesives, in addition to certain requirements for conductivity and bonding strength, also have specific requirements, such as high temperature resistance, ultra-low temperature resistance, instant curing, anisotropy, and transparency.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A transient diode, characterized in that, include: Device body; The main body of the device includes: at least one first bidirectional semiconductor chip, at least one second bidirectional semiconductor chip, and a conductive layer; A conductive layer is disposed between the first bidirectional semiconductor chip and the second bidirectional semiconductor chip, so that the first bidirectional semiconductor chip and the second bidirectional semiconductor chip are connected in series; wherein, the first bidirectional semiconductor chip is a bidirectional semiconductor chip with an N-type substrate, and the second bidirectional semiconductor chip is a bidirectional semiconductor chip with a P-type substrate.

2. The transient diode according to claim 1, characterized in that, The bidirectional semiconductor chip with the N-type substrate includes: an N-type substrate, a first P-type doped layer, and a second P-type doped layer; The first P-type doped layer, the N-type substrate, and the second P-type doped layer are stacked sequentially; the first P-type doped layer or the second P-type doped layer is connected to the conductive layer.

3. The transient diode according to claim 1, characterized in that, A first P-type doped layer is formed by doping P-type semiconductor ions under a first surface of the N-type substrate; a second P-type doped layer is formed by doping P-type semiconductor ions under a second surface of the N-type substrate; wherein the first surface and the second surface are opposite surfaces; the area of ​​the first P-type doped layer projected perpendicularly onto the first surface is smaller than the area of ​​the first surface, and the area of ​​the second P-type doped layer projected perpendicularly onto the second surface is smaller than the area of ​​the second surface.

4. The transient diode according to claim 2 or 3, characterized in that, The first P-type doped layer and the second P-type doped layer are centrally symmetrical about the N-type substrate.

5. The transient diode according to claim 1, characterized in that, The bidirectional semiconductor chip with the P-type substrate includes: a P-type substrate, a first N-type doped layer, and a second N-type doped layer; the first N-type doped layer, the P-type substrate, and the second N-type doped layer are stacked sequentially; the first N-type doped layer or the second N-type doped layer is connected to the conductive layer.

6. The transient diode according to claim 5, characterized in that, The first N-type doped layer is formed by doping N-type semiconductor ions under the first surface of the P-type substrate; the second N-type doped layer is formed by doping N-type semiconductor ions under the second surface of the P-type substrate; wherein the first surface and the second surface are opposite surfaces; the area of ​​the first N-type doped layer projected perpendicularly onto the first surface is smaller than the area of ​​the first surface, and the area of ​​the second N-type doped layer projected perpendicularly onto the second surface is smaller than the area of ​​the second surface.

7. The transient diode according to claim 5 or 6, characterized in that, The first N-type doped layer and the second N-type doped layer are centrally symmetrical about the P-type substrate.

8. The transient diode according to claim 1, characterized in that, It also includes a packaging layer; The encapsulation layer covers the surface of the device body.

9. The transient diode according to claim 8, characterized in that, The encapsulation layer includes at least one of silicone resin and epoxy resin.

10. The transient diode according to claim 1, characterized in that, The conductive layer includes conductive adhesive.

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