A zener diode and a method for manufacturing a zener diode

Abstract

The Zener diode and the Zener diode manufacturing method provided by the embodiment of the application, the Zener diode comprises a substrate and a doped region located on one side of the substrate. The doped region comprises a ring-shaped doped region and a center doped region located in the center region of the ring-shaped doped region, the ring-shaped doped region comprises a first ring-shaped doped region and a second ring-shaped doped region, wherein the first ring-shaped doped region is located at the periphery of the center doped region, the second ring-shaped doped region is located at the periphery of the first ring-shaped doped region, and the doping depth of the first ring-shaped doped region is greater than the doping depth of the center doped region and the doping depth of the second ring-shaped doped region. In this way, when a reverse breakdown voltage is applied to the Zener diode, the Zener diode can be broken down twice, first, the center doped region is broken down, and then the ring-shaped doped region is broken down. Since the diameter of the center doped region is small, the leakage current generated is small, and the breakdown characteristics of the product can be improved.

Description

Technical Field

[0001] This application relates to the field of semiconductor device technology, and more specifically, to a Zener diode and a method for manufacturing a Zener diode. Background Technology

[0002] A Zener diode, also known as a Zener diode, is a semiconductor device that maintains high resistance up to a critical reverse breakdown voltage. When the reverse voltage reaches this critical value, the reverse current increases sharply, a phenomenon known as breakdown. Above this critical breakdown voltage, the reverse resistance drops sharply to a very small value. Despite current variations over a wide range, the voltage across the Zener diode remains essentially stable near this breakdown voltage, thus achieving voltage regulation. In recent years, with the booming development of the electronics manufacturing industry, Zener diodes have found wide application in automotive electronics, motor control, charging piles, welding machines, air conditioners, and other devices.

[0003] Zener diodes typically exhibit significant reverse leakage current during reverse breakdown. Before reaching the regulated voltage, the leakage current can become quite high, limiting their use in some demanding circuit designs. Summary of the Invention

[0004] In order to overcome the technical problems mentioned in the above technical background, this application provides a Zener diode and a method for manufacturing a Zener diode.

[0005] A first aspect of this application provides a Zener diode, the Zener diode including a substrate, a doped region located on one side of the substrate;

[0006] The doped region includes a ring-shaped doped region and a central doped region located in the central region of the ring-shaped doped region;

[0007] The annular doped region includes a first annular doped region and a second annular doped region, wherein the first annular doped region is located on the outer periphery of the central doped region, and the second annular doped region is located on the outer periphery of the first annular doped region;

[0008] The doping depth of the first annular doped region is greater than the doping depth of the central doped region and the doping depth of the second annular doped region;

[0009] The annular width of the annular doped region is greater than the diameter of the central doped region.

[0010] In the above structure, the doping depth of the first annular doped region is greater than the doping depth of the central doped region and the doping depth of the second annular doped region, and the annular width of the first annular doped region is greater than the diameter of the central doped region. With this configuration, when a reverse breakdown voltage is applied across the Zener diode, breakdown can occur in two stages: first, the area corresponding to the central doped region breaks down, and then the area corresponding to the entire annular doped region breaks down. Because the diameter of the central doped region is smaller, the leakage current is smaller, thus improving the breakdown characteristics of the product.

[0011] In one possible embodiment of this application, the annular doped region is an annular doped region with a fixed annular width.

[0012] In one possible embodiment of this application, the Zener diode further includes a cutoff ring, which is located on the same side of the substrate as the annular doped region and on the outer periphery of the annular doped region, and the cutoff ring is not in contact with the annular doped region.

[0013] In one possible embodiment of this application, the annular width of the annular doped region ranges from 75 to 100 μm, and the length of the central doped region ranges from 35 to 60 μm.

[0014] In one possible embodiment of this application, the ring width of the annular doped region is 85 μm, and the diameter of the central doped region is 50 μm.

[0015] In one possible embodiment of this application, the substrate is a heavily doped N-type substrate, and the annular doped region and the central doped region are P-type doped regions; or,

[0016] The substrate is a heavily doped P-type substrate, and the annular doped region and the central doped region are N-type doped regions.

[0017] A second aspect of this application provides a method for manufacturing a Zener diode, the method comprising:

[0018] Provide a substrate;

[0019] An annular doping region window is formed on one side of the substrate, and the substrate is first doped through the annular doping window;

[0020] An active region window is formed on the same side of the substrate, and the substrate is doped a second time through the active region window. The active region window is circular, and the center of the active region window coincides with the center of the annular doping window. The radius of the active region window is smaller than the radius of the outer circumference of the annular doping window. In the substrate corresponding to the active region window, the annular width of the region doped twice is greater than the diameter of the region doped once.

[0021] In one possible embodiment of this application, the step of providing a substrate further includes:

[0022] The substrate is heavily doped to obtain a doped substrate.

[0023] In one possible embodiment of this application, the step of forming an annular doping window on one side of the substrate and doping the substrate through the annular doping window includes:

[0024] A photoresist layer is formed on one side of the substrate;

[0025] An annular doped window is formed on the photoresist layer by etching the photoresist layer;

[0026] The substrate is doped through the annular doping window using ion implantation and / or ion diffusion.

[0027] In one possible embodiment of this application, the step of forming an active region window on the same side of the substrate and performing a second doping on the substrate through the active region window includes:

[0028] A photoresist layer is formed on the same side of the substrate;

[0029] An active region window is formed on the photoresist layer by etching the photoresist layer;

[0030] The substrate is doped through the active region window using ion implantation and / or ion diffusion.

[0031] Compared to existing technologies, the Zener diode and its fabrication method provided in this application have a first annular doped region with a doping depth greater than that of the central doped region and the second annular doped region, and a wider annular width than that of the central doped region. With this configuration, when a reverse breakdown voltage is applied across the Zener diode, breakdown can occur in two stages: first, breakdown occurs at the location corresponding to the central doped region, and then breakdown occurs at the location corresponding to the entire annular doped region. Because the diameter of the central doped region is smaller, the leakage current is lower, thus improving the breakdown characteristics of the product. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1A top view of the Zener diode provided in an embodiment of this application is illustrated;

[0034] Figure 2 A schematic diagram illustrating a possible structure of the Zener diode provided in an embodiment of this application is shown;

[0035] Figure 3 An impedance comparison diagram is provided for the Zener diode provided in this application embodiment and a conventional Zener diode.

[0036] Figure 4 An example is shown in the reverse leakage current comparison diagram between the Zener diode provided in the embodiments of this application and a conventional Zener diode;

[0037] Figure 5 A comparison diagram of the breakdown characteristic curves of the Zener diode provided in the embodiments of this application and that of existing Zener diodes is shown;

[0038] Figure 6 A flowchart illustrating the Zener diode fabrication method provided in an embodiment of this application is illustrated.

[0039] Figure 7 Example Figure 6 The manufacturing process diagram of the method shown is illustrated.

[0040] Main labels:

[0041] 10 - Substrate; 20 - Doped region; 201 - First annular doped region; 202 - Second annular doped region; 203 - Central doped region; 30 - Cut-off ring; 40 - Annular doped region window; 50 - Active region window. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0043] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0044] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0045] In the description of this application, it should be noted that the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this application is usually placed when in use. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0046] It should be noted that, where there is no conflict, different features in the embodiments of this application can be combined with each other.

[0047] To address the technical problems mentioned in the background section, the inventor has innovatively designed the following technical solution, the specific implementation of which will be described in detail below with reference to the accompanying drawings.

[0048] Please refer to Figure 1 , Figure 1 This illustration shows one possible structural diagram of a Zener diode 1 provided in an embodiment of this application. The Zener diode 1 may include a substrate 10 and a doped region 20. The doped region 20 may include a ring-shaped doped region composed of a first ring-shaped doped region 201 and a second ring-shaped doped region 202, and a central doped region 203. The central doped region 203 is located in the central region of the ring-shaped doped region, that is, the central doped region 203 is located in the annular center of the ring-shaped doped region. The first ring-shaped doped region is located on the outer periphery of the central doped region 203, and the second ring-shaped doped region 202 is located on the outer periphery of the first ring-shaped doped region, such that the inner circumference of the first ring-shaped doped region coincides with the outer circumference of the central doped region 203, and the inner circumference of the second ring-shaped doped region 202 coincides with the outer circumference of the first ring-shaped doped region.

[0049] In this embodiment, the doping depth of the first annular doped region is greater than the doping depth of the central doped region 203 and the doping depth of the second annular doped region 202. Specifically, the doping depths of the first annular doped region 201, the second annular doped region 202, and the central doped region 203 can be controlled by the diffusion time or diffusion concentration during doping to form gradient junctions with different junction depths. For example, in this embodiment, the first annular doped region can be formed by two doping operations, while the second annular doped region 202 and the central doped region 203 can be formed by a single doping operation. The annular width d1 of the annular doped region is greater than the diameter d2 of the central doped region, where the annular width d1 is the difference between the outer and inner circumference radii of the annular doped region, the central doped region 203 is circular, and the diameter d2 of the central doped region 203 is the diameter of the central doped region 203.

[0050] In existing Zener diodes, the width of the annular doped region is smaller than the diameter of the central doped region. When a reverse breakdown voltage is applied across the Zener diode, it only breaks down once at the location corresponding to the central doped region, resulting in significant leakage current. In contrast, the Zener diode provided in this application has a first annular doped region 201 with a doping depth greater than both the central doped region 203 and the second annular doped region 202, and the width of the annular doped region is greater than the diameter of the central doped region 203. With this configuration, when a reverse breakdown voltage is applied across the Zener diode, it can break down in two stages: first, the location corresponding to the central doped region 203 breaks down, and then the entire annular doped region breaks down. Because the diameter of the central doped region 203 is smaller, the resulting leakage current is smaller, thus improving the breakdown characteristics of the product.

[0051] In this embodiment, the annular doped region can be a fixed annular width d1, meaning the outer and inner circumferences of the annular doped region are concentric. This configuration allows the corresponding positions of the annular doped region to break down simultaneously during subsequent reverse breakdown.

[0052] Furthermore, in the embodiments of this application, the Zener diode 1 may also include a cutoff ring 30, which is located on the same side of the substrate 10 as the annular doped region 20 and is located on the outer periphery of the annular doped region 20. The cutoff ring 30 and the annular doped region 20 are not in contact. The cutoff ring 30 can prevent leakage of the Zener diode 1.

[0053] Furthermore, in this embodiment, the annular width of the annular doped region can range from 75 to 100 μm, and the length of the central doped region 203 can range from 35 to 60 μm. Further, the annular width of the annular doped region is 85 μm, and the diameter of the central doped region is 50 μm.

[0054] The following description uses experimental data from existing Zener diodes and the Zener diode provided in this application to illustrate the difference. For example, in existing Zener diodes, the ring width of the ring-doped region is 10 μm and the length of the central doped region 203 is 200 μm; in the Zener diode of this application, the ring width of the ring-doped region is 50 μm and the length of the central doped region 203 is 85 μm.

[0055] Please refer to Figure 3 With the same leakage current Iz, the impedance value of the Zener diode provided in this application is less than the impedance value of the Zener diode in the prior art.

[0056] Please refer to Figure 4 Furthermore, while maintaining the same breakdown voltage, the leakage current of the Zener diode provided in this application is much smaller than that of the Zener diodes in the prior art.

[0057] Please refer to Figure 5 The horizontal axis represents the applied reverse voltage, and the vertical axis represents the leakage current. The Zener diode provided in this application has a steady increase in leakage current during breakdown, while the Zener diode in the prior art has a rapid increase in leakage current during breakdown. Compared with the Zener diode in the prior art, the Zener diode provided in this application can improve the breakdown characteristics.

[0058] Please refer to Figure 6 and Figure 7 , Figure 6 This paper illustrates a schematic diagram of the fabrication method of a Zener diode according to an embodiment of this application. Figure 7 It shows Figure 6 The corresponding process flow diagram. (See below for details.) Figure 6 and Figure 7 The fabrication method of aligning nanodiodes is described.

[0059] Step S101: Provide a substrate 10.

[0060] In step S102, an annular doping window 40 is formed on one side of the substrate, and the substrate is first doped through the annular doping window 40.

[0061] In step S103, an active region window 50 is formed on the same side of the substrate, and the substrate 10 is doped a second time through the active region window 50. The active region window 50 is circular, and its center coincides with the center of the annular doping window. The radius of the active region window 50 is smaller than the radius of the outer circumference of the annular doping window. In the substrate 10 corresponding to the active region window 50, the annular width of the region doped twice is greater than the diameter of the region doped once.

[0062] In this embodiment of the application, in step S101, the provided substrate 10 is heavily doped to obtain the doped substrate 10.

[0063] Furthermore, in the embodiments of this application, step S102 can be implemented in the following manner.

[0064] First, a photoresist layer is formed on one side of the substrate 10;

[0065] Next, an annular doped window 40 is formed on the photoresist layer by etching;

[0066] Finally, the substrate 10 is doped through the annular doping window 40 by ion implantation and / or ion diffusion.

[0067] Furthermore, in the embodiments of this application, step S103 can be implemented in the following manner.

[0068] First, a photoresist layer is formed on the same side of the substrate 10;

[0069] Next, an active region window 50 is formed on the photoresist layer by etching;

[0070] Finally, the substrate 10 is doped through the active region window 50 by ion implantation and / or ion diffusion.

[0071] By using the methods described above, stable process control can be ensured, resulting in Zener diodes with good reliability.

[0072] In summary, the Zener diode and its fabrication method provided in this application have a first annular doped region with a doping depth greater than that of the central doped region and the second annular doped region, and the annular width of the first annular doped region is greater than the diameter of the central doped region. With this configuration, when a reverse breakdown voltage is applied across the Zener diode, breakdown can occur in two stages: first, the area corresponding to the central doped region breaks down, and then the entire annular doped region breaks down. Because the diameter of the central doped region is smaller, the leakage current is smaller, thus improving the breakdown characteristics of the product.

[0073] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for manufacturing a Zener diode, characterized in that, The method includes: Provide a substrate; An annular doping window is formed on one side of the substrate, and the substrate is first doped through the annular doping window; An active region window is formed on the same side of the substrate, and the substrate is doped a second time through the active region window. The active region window is circular, and the center of the active region window coincides with the center of the annular doping window. The radius of the active region window is smaller than the radius of the outer circumference of the annular doping window. Specifically, after the first doping and the second doping, a ring-shaped doped region and a central doped region located in the center of the ring-shaped doped region are formed in the substrate; the ring-shaped doped region includes a first ring-shaped doped region and a second ring-shaped doped region, the first ring-shaped doped region is located on the outer periphery of the central doped region, the second ring-shaped doped region is located on the outer periphery of the first ring-shaped doped region, the doping depth of the first ring-shaped doped region is greater than the doping depth of the central doped region and the doping depth of the second ring-shaped doped region, and the ring width of the ring-shaped doped region is greater than the diameter of the central doped region.

2. The method for manufacturing a Zener diode as described in claim 1, characterized in that, The step of providing a substrate further includes: The substrate is heavily doped to obtain a doped substrate.

3. The method for manufacturing a Zener diode as described in claim 1, characterized in that, The step of forming an annular doping window on one side of the substrate and doping the substrate through the annular doping window includes: A photoresist layer is formed on one side of the substrate; An annular doped window is formed on the photoresist layer by etching the photoresist layer; The substrate is doped through the annular doping window using ion implantation and / or ion diffusion.

4. The method for manufacturing a Zener diode as described in claim 3, characterized in that, The step of forming an active region window on the same side of the substrate and performing a second doping on the substrate through the active region window includes: A photoresist layer is formed on the same side of the substrate; An active region window is formed on the photoresist layer by etching the photoresist layer; The substrate is doped through the active region window using ion implantation and / or ion diffusion.

5. A Zener diode, characterized in that, The Zener diode is manufactured by the Zener diode manufacturing method according to any one of claims 1-4; The Zener diode includes a substrate and a doped region located on one side of the substrate; The doped region includes a ring-shaped doped region and a central doped region located in the central region of the ring-shaped doped region; The annular doped region includes a first annular doped region and a second annular doped region, wherein the first annular doped region is located on the outer periphery of the central doped region, and the second annular doped region is located on the outer periphery of the first annular doped region; The doping depth of the first annular doped region is greater than the doping depth of the central doped region and the doping depth of the second annular doped region; The annular width of the annular doped region is greater than the diameter of the central doped region.

6. The Zener diode as described in claim 5, characterized in that, The annular doped region is an annular doped region with a fixed annular width.

7. The Zener diode as described in claim 6, characterized in that, The Zener diode further includes a cutoff ring, which is located on the same side of the substrate as the annular doped region and on the outer periphery of the annular doped region. The cutoff ring and the annular doped region are not in contact.

8. The Zener diode as described in claim 5, characterized in that, The annular width of the annular doped region ranges from 75 to 100 μm, and the length of the central doped region ranges from 35 to 60 μm.

9. The Zener diode as described in claim 8, characterized in that, The annular width of the annular doped region is 85 μm, and the diameter of the central doped region is 50 μm.

10. The Zener diode as described in any one of claims 5-9, characterized in that, The substrate is a heavily doped N-type substrate, and the annular doped region and the central doped region are P-type doped regions; or, The substrate is a heavily doped P-type substrate, and the annular doped region and the central doped region are N-type doped regions.

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