Electrostatic discharge diode and circuit structure

Abstract

The utility model provides an electrostatic discharge diode and a circuit structure. The electrostatic discharge diode comprises a substrate, an ion trap and a grid electrode. The ion trap is located in the substrate, the ion trap is provided with a first injection region and a second injection region which are arranged at an interval, and the ion trap extends to the interval between the first injection region and the second injection region; the grid electrode is located on the upper surface of the spaced ion trap between the first implantation region and the second implantation region. According to the above configuration, on one hand, the grid electrode is designed above the position of the isolation structure between the original first injection region and the second injection region of the diode, so that the isolation structure between the original first injection region and the second injection region of the diode is removed; according to the utility model, the conduction current of the diode is added with the conduction current of the lateral (left-right direction) cross section besides the original conduction current of the cross section downward to the bottom layer, so that the overall conduction current of the diode can be increased, and the electrostatic discharge capability of the diode is greatly improved.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductors, in particular to an electrostatic discharge diode and a circuit structure. Background Art

[0002] With the widespread application of integrated circuits and the continuous advancement of chip technology, electrostatic discharge (ESD) protection of chips has become increasingly important. Static electricity is ubiquitous in the manufacturing, packaging, testing and use of chips. The accumulated static charge is released in nanoseconds to microseconds with a current of several amperes or tens of amperes, and the instantaneous power is as high as tens or hundreds of watts, which can cause great damage to the chip. Diodes are widely used devices in chip design, and the electrostatic protection performance of diodes is crucial to chips.

[0003] Figure 1 This is a cross-sectional view of an electrostatic discharge diode in the prior art. Diodes are often used as electrostatic discharge protection elements. The lateral cross-sections of the P-pole (anode) and N-pole (cathode) of the process structure of the traditional electrostatic discharge diode are blocked by the shallow trench isolation (STI) structure of the semiconductor process, specifically the first shallow trench isolation structure 51, resulting in the cross-section of the diode effectively conducting current only having the bottom cross-section in the downward direction, and no side cross-section in the left and right directions. In addition, the N+ junction (cathode) is also surrounded by the second shallow trench isolation structure 52.

[0004] Since the electron flow needs to bypass the first shallow trench isolation structure 51 to reach the N pole from the P pole to realize the conduction of the electrostatic discharge diode, the energy of the electron flow required for this process is relatively high, that is, the diode's turn-on resistance is relatively large, the diode needs to be turned on at a higher voltage, and the clamping voltage of the diode is larger. Therefore, the traditional electrostatic discharge diode has a greater barrier to static electricity when releasing static electricity, so that static electricity is not easily discharged, which leads to limited electrostatic discharge capability of the diode. Utility Model Content

[0005] The utility model aims to provide an electrostatic discharge diode and a circuit structure to solve the problem that the electrostatic discharge capability and stability of the current electrostatic discharge diode are limited.

[0006] In order to solve the above technical problems, based on one aspect of the present utility model, the present utility model provides an electrostatic discharge diode, which includes:

[0007] substrate;

[0008] An ion trap, the ion trap being located in the substrate, the ion trap having a first injection region and a second injection region spaced apart from each other, and the ion trap extending to the space between the first injection region and the second injection region;

[0009] A gate is located on an upper surface of the ion well between the first injection region and the second injection region.

[0010] Optionally, the first injection region is a P-type injection region, the second injection region is an N-type injection region, and the ion well is an N-type well.

[0011] Optionally, the gate is a polysilicon gate.

[0012] Optionally, the second injection region surrounds the first injection region, and the gate surrounds the first injection region.

[0013] Optionally, the electrostatic discharge diode further includes an isolation structure, and the isolation structure surrounds the second injection region.

[0014] Optionally, the isolation structure includes a shallow trench isolation structure.

[0015] Optionally, the shape enclosed by the gate, the shape enclosed by the second injection region, and the shape enclosed by the isolation structure are the same, and the shape enclosed by the gate matches the shape of the first injection region.

[0016] Based on another aspect of the utility model, the utility model also provides a circuit structure, which includes the electrostatic discharge diode as described above.

[0017] In summary, in the electrostatic discharge diode and circuit structure provided by the utility model, the electrostatic discharge diode includes a substrate, an ion trap and a gate; the ion trap is located in the substrate, and the ion trap has a first injection area and a second injection area arranged at intervals, and the ion trap extends to the interval between the first injection area and the second injection area; the gate is located on the upper surface of the ion trap in the interval between the first injection area and the second injection area. In this configuration, in the first aspect, the utility model designs a gate above the position of the isolation structure between the original first injection area and the second injection area of ​​the diode, thereby removing the isolation structure between the original first injection area and the second injection area of ​​the diode, so that the conduction current of the diode of the utility model is increased in addition to the original conduction current downward to the bottom cross section, and the conduction current of the lateral (left and right direction) cross section is increased, thereby increasing the conduction current of the diode as a whole, greatly improving the electrostatic discharge capability of the diode. In the second aspect, the design layout of the gate can act as a mask, which is conducive to the laser self-alignment method in the process, accurately aligning and positioning the position of the first injection area and the position of the second injection area of ​​the diode, avoiding the electrical property change of the diode caused by the alignment offset in the process and affecting the electrostatic discharge capability and stability of the diode.

[0018] It should be noted that, since the circuit structure includes the electrostatic discharge diode, it also has the technical effects brought by the electrostatic discharge diode, which will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Those skilled in the art should understand that the drawings provided are for a better understanding of the present invention and do not constitute any limitation on the scope of the present invention.

[0020] Figure 1 is a cross-sectional view of an electrostatic discharge diode in the prior art;

[0021] Figure 2 is a cross-sectional view of an electrostatic discharge diode according to an embodiment of the utility model;

[0022] Figure 3 It is a top view of an electrostatic discharge diode according to an embodiment of the utility model.

[0023] In the attached figure:

[0024] 100 - substrate; 10 - ion well; 20 - first injection region; 30 - second injection region; 40 - gate; 50 - isolation structure; 51 - first shallow trench isolation structure; 52 - second shallow trench isolation structure. DETAILED DESCRIPTION

[0025] In order to make the purpose, advantages and features of the utility model clearer, the utility model is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the utility model. In addition, the structure shown in the drawings is often a part of the actual structure. In particular, the emphasis of each drawing is different, and sometimes different scales are used.

[0026] As used in the present invention, the singular forms "one", "an" and "the" include plural objects, the term "or" is usually used to include the meaning of "and / or", the term "several" is usually used to include the meaning of "at least one", and the term "at least two" is usually used to include the meaning of "two or more". In addition, the terms "first", "second" and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second" and "third" may explicitly or implicitly include one or at least two of the features, "one end" and "the other end" and "the proximal end" and "the distal end" generally refer to two corresponding parts, which not only include the endpoints, and the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. In addition, as used in the present invention, an element disposed on another element generally only indicates that there is a connection, coupling, cooperation or transmission relationship between the two elements, and the connection, coupling, cooperation or transmission between the two elements may be direct or indirect through an intermediate element, and cannot be understood as indicating or implying the spatial position relationship between the two elements, that is, an element may be in any orientation such as inside, outside, above, below or on one side of another element, unless otherwise clearly indicated in the content. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] Figure 2 1 is a cross-sectional view of an electrostatic discharge diode according to an embodiment of the present invention. Figure 2, an embodiment of the utility model schematically provides an electrostatic discharge diode, the electrostatic discharge diode comprising a substrate 100, an ion well 10 and a gate 40, the ion well 10 is located in the substrate 100, and the ion well 10 has a first injection region 20 and a second injection region 30 arranged at intervals, and the ion well 10 extends to the interval between the first injection region 20 and the second injection region 30, it should be noted that the top surfaces of the first injection region 20 and the second injection region 30 are exposed to the substrate 100, so as to facilitate electrical connection with an external circuit. It can be understood by those skilled in the art that a PN junction is formed between the first injection region 20 and the second injection region 30. In one embodiment, the first injection region 20 is a P-type injection region, doped with P-type ions, the second injection region 30 is an N-type injection region, doped with N-type ions, and the ion well 10 is an N-type well. The gate 40 is located on the upper surface of the ion well 10 in the interval between the first injection region 20 and the second injection region 30, and the gate 40 is connected to an external bias voltage, and the gate 40 can be, for example, a polysilicon gate 40.

[0028] With such configuration, on the one hand, the utility model designs a gate 40 above the position of the isolation structure between the original first injection region 20 and the second injection region 30 of the diode, thereby removing the isolation structure (first shallow trench isolation structure 51) between the original first injection region 20 and the second injection region 30 of the diode, so that the conduction current of the diode of the utility model is increased in addition to the original conduction current downward to the bottom cross section, and the conduction current of the lateral (left and right direction) cross section is increased, thereby increasing the conduction current of the diode as a whole, greatly improving the electrostatic discharge capability of the diode. On the other hand, the design layout of the gate 40 can act as a mask, which is conducive to the laser self-alignment method in the process, accurately aligning and positioning the position of the first injection region 20 of the diode and the position between the second injection region 30, avoiding the change of the electrical properties of the diode caused by the alignment offset in the process and affecting the electrostatic discharge capability and stability of the diode. It should be noted that if only the original isolation structure of the diode (specifically the first shallow trench isolation structure 51 here) is removed without designing the gate 40, although the conduction current of the diode's lateral cross-section can be increased, it is easy for the first injection region 20 and the second injection region 30 to shift during the laser self-alignment process, causing the electrical properties of the diode to change, thereby affecting the diode's electrostatic discharge capability.

[0029] Figure 3 FIG. 1 is a top view of an electrostatic discharge diode according to an embodiment of the present invention. Figure 3, further, the second injection region 30 surrounds the first injection region 20, and the gate 40 surrounds the first injection region 20. That is, the second injection region 30 is annular and surrounds the first injection region 20, and the gate 40 is annular and surrounds the first injection region 20, and in the left and right directions, the second injection region 30 surrounds the gate 40. Furthermore, the electrostatic discharge diode also includes an isolation structure 50 (the isolation structure 50 here is equivalent to a second shallow trench isolation structure 52), the isolation structure 50 is annular and surrounds the second injection region 30. The isolation structure 50 can be a shallow trench isolation structure 50 (STI).

[0030] Continue reading Figure 3 In one embodiment, the shapes enclosed by the gate 40, the shapes enclosed by the second injection region 30, and the shapes enclosed by the isolation structure 50 are the same, and the shapes enclosed by the gate 40 are compatible with the shapes of the first injection region 20. For example, for example, the shapes enclosed by the gate 40, the shapes enclosed by the second injection region 30, and the shapes enclosed by the isolation structure 50 are all rectangular rings, and the shape of the first injection region 20 is rectangular.

[0031] Based on the above-mentioned electrostatic discharge diode, the utility model also provides a circuit structure, which includes the above-mentioned electrostatic discharge diode. It can be understood by those skilled in the art that the design purpose of the electrostatic discharge diode is to prevent the circuit structure from being damaged by ESD discharge when the circuit structure is working normally; when the circuit structure is working normally, the electrostatic discharge diode is in a cut-off state (high resistance state), which will not affect the normal operation of the circuit structure; when the circuit has an abnormal overvoltage and reaches the breakdown voltage of the electrostatic discharge diode, it will quickly change from a high resistance state to a low resistance state, providing a low impedance conduction path, thereby protecting the circuit structure from damage.

[0032] Although the utility model is disclosed as above with preferred embodiments, the above embodiments are not intended to limit the utility model. For any technician familiar with the art, without departing from the scope of the technical solution of the utility model, the above disclosed technical content can be used to make many possible changes and modifications to the technical solution of the utility model, or modified into equivalent embodiments with equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the utility model without departing from the content of the technical solution of the utility model still falls within the scope of protection of the technical solution of the utility model.

Claims

1. An electrostatic discharge diode, characterized in that: include: substrate; An ion trap, the ion trap being located in the substrate, the ion trap having a first injection region and a second injection region spaced apart from each other, and the ion trap extending to the space between the first injection region and the second injection region; A gate is located on an upper surface of the ion well between the first injection region and the second injection region.

2. The electrostatic discharge diode according to claim 1, characterized in that: The first implantation region is a P-type implantation region, the second implantation region is an N-type implantation region, and the ion well is an N-type well.

3. The electrostatic discharge diode according to claim 1, characterized in that: The gate is a polysilicon gate.

4. The electrostatic discharge diode according to claim 1, characterized in that: The second implantation region surrounds the first implantation region, and the gate surrounds the first implantation region.

5. The electrostatic discharge diode according to claim 4, characterized in that: The electrostatic discharge diode further includes an isolation structure surrounding the second implantation region.

6. The electrostatic discharge diode according to claim 5, characterized in that: The isolation structure includes a shallow trench isolation structure.

7. The electrostatic discharge diode according to claim 5, characterized in that: The shape enclosed by the gate, the shape enclosed by the second injection region, and the shape enclosed by the isolation structure are the same, and the shape enclosed by the gate matches the shape of the first injection region.

8. A circuit structure, characterized in that: The electrostatic discharge diode comprises the electrostatic discharge diode as claimed in any one of claims 1 to 7.

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