Novel ectopic triggering SCR (Selective Catalytic Reduction) structure

Abstract

The utility model, which belongs to the technical field of the semiconductor device, discloses a novel ectopic trigger SCR structure comprising a first conductive type substrate. The first conductive type well region is arranged in the first conductive type substrate; the second conductive type well region is arranged on one side of the first conductive type well region; a first trigger region disposed in the second conductive type well region; the second trigger region stretches across the junction of the first conductive type substrate and the first conductive type well region, the bottom of the second trigger region is further connected with a deep well region, the first trigger region, the second trigger region and the deep well region are all of a second conductive type, and the first trigger region and the second trigger region are connected through metal at the top. The current is divided into two parts by adding the first trigger region and the second trigger region which are connected with each other, so that the trigger point and the trigger direction of the device are controlled, the voltage and current characteristics of the SCR device are improved, and the novel ectopic trigger SCR structure can better maintain the voltage and failure current characteristics.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of semiconductor devices, especially to a novel ectopic trigger SCR structure. BACKGROUND

[0002] ESD is a kind of ancient natural phenomenon, which exists in every corner of people's daily life. However, such a common electrical phenomenon is a fatal threat to precision integrated circuits. Electrical surge / transient voltage refers to the random and high voltage or large current that suddenly appears in the circuit, which is characterized by short occurrence time and very large instantaneous energy. Electrical surge has strong destructive effect on electronic components and integrated circuits, which can induce logic circuit misoperation, and even cause secondary breakdown of triode, latch effect of complementary metal oxide semiconductor (CMOS) and other serious thermal effects, resulting in failure of devices or integrated circuits. Electrical surge usually has two random sources, one is the instability of power grid, such as sudden switching on-off, sudden start of capacitive or inductive load, hot plug of related equipment, unstable operation of related power supply, etc. The second is external sudden interference, such as lightning and electrostatic discharge.

[0003] With the improvement of integrated circuit manufacturing process, the minimum line width has been reduced to sub-micron or even nanometer level, which brings improvement of chip performance, but also greatly reduces the ESD resistance of integrated circuits, so the damage of static electricity is more serious. Most of the ESD can cause non-fatal damage to integrated circuits, thereby reducing the service life and reliability of integrated circuits, and further causing degradation of system function, which greatly hinders the realization of large-scale high-reliability integration.

[0004] In order to realize an ESD device with excellent holding voltage and failure current characteristics, the utility model discloses a novel ectopic trigger SCR structure based on the traditional SCR device structure as shown in the utility model Figure 1 The novel cathode metal structure and the novel device triggering mode are used. Figure 2 The novel ectopic trigger SCR structure is disclosed.

[0005] It should be noted that the information disclosed in the background technology part of the utility model is only intended to deepen the understanding of the general background technology of the utility model, and should not be regarded as acknowledging or implying in any form that the information constitutes prior art known to those skilled in the art. CONTENT OF THE UTILITY MODEL

[0006] The utility model aims to provide a novel ectopic trigger SCR structure to solve the problem of holding voltage and failure current of ESD device.

[0007] To solve the above technical problems, the utility model provides a novel ectopic trigger SCR structure, including:

[0008] The first conductive type base;

[0009] The first conductive type well region is arranged in the first conductive type base;

[0010] The second conductive type well region is arranged at one side of the first conductive type well region;

[0011] The first trigger region is arranged in the second conductive type well region;

[0012] The second trigger region is across the junction of the first conductive type base and the first conductive type well region, and the bottom of the second trigger region is further connected with a deep well region, wherein the first trigger region and the second trigger region, the deep well region are all the second conductive type, and the first trigger region and the second trigger region are connected through the metal interconnection of the top.

[0013] Preferably, the first conductive type base is P type base, the first conductive type well region is P type well region, and the second conductive type well region is first N type well region.

[0014] Preferably, the first N type trigger region is arranged in the first N type well region, and the second N type trigger region is arranged at the junction of the P type well region and the P type base.

[0015] Preferably, the bottom of the second N type trigger region is further connected with the second N type well region, and one side of the second N type well region is further connected with the sidewall of the P type well region.

[0016] Preferably, the anode P type region is further arranged in the first N type well region, one side of the anode P type region is connected with the anode N type region, and the other side is arranged with the first N type trigger region at intervals.

[0017] Preferably, the utility model further includes an oxide layer arranged at the top of the P type base.

[0018] Preferably, the anode N type region and the anode P type region are correspondingly covered with the anode metal on the oxide layer at the top, and the anode metal is connected with the anode N type region and the anode P type region through the perforation on the oxide layer.

[0019] Preferably, the cathode N type region is further arranged in the P type well region, one side of the cathode N type region is connected with the cathode P type region, and the other side is arranged with the second N type trigger region at intervals.

[0020] Preferably, the cathode N type region and the cathode P type region are correspondingly covered with the first cathode metal on the oxide layer at the top, and the first cathode metal is connected with the cathode N type region and the cathode P type region through the perforation on the oxide layer.

[0021] Preferably, a second cathode metal is arranged on the oxide layer, the second cathode metal is concave and surrounds part of the first cathode metal, two sides of the second cathode metal are covered on the oxide layer on top of the first N-type trigger area and the second N-type trigger area, and the second cathode metal connects the first N-type trigger area and the second N-type trigger area through a through hole on the oxide layer.

[0022] In the novel ectopic trigger SCR structure, the current is divided into two parts by the interconnected first trigger area and the second trigger area, so as to control the trigger point and the trigger direction of the device. BRIEF DESCRIPTION OF DRAWINGS

[0023] Those skilled in the art will understand that the provided drawings are for better understanding of the utility model and do not constitute any limitation on the scope of the utility model.

[0024] Figure 1 is a schematic diagram of a traditional SCR device structure;

[0025] Figure 2 is a schematic diagram of a novel ectopic trigger SCR structure of an embodiment of the utility model;

[0026] Figure 3 is a schematic diagram of a current trigger path of the novel ectopic trigger SCR structure of an embodiment of the utility model;

[0027] Figure 4 is a schematic diagram of a novel ectopic trigger SCR structure of another embodiment of the utility model.

[0028] In the drawings:

[0029] 101, P-type substrate; 102, first N-type well region; 103, P-type well region; 104, second N-type well region; 105, anode N-type region; 106, anode P-type region; 107, first N-type trigger area; 108, cathode P-type region; 109, cathode N-type region; 110, second N-type trigger area; 111, oxide layer; 112, anode metal; 113, first cathode metal; 114, second cathode metal; 115, N-type substrate; 116, P-type deep well region. DETAILED DESCRIPTION

[0030] To make the purposes, advantages and characteristics of the present application more clear, the present application will be further described in detail below in combination with the 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 facilitate and clearly assist in the purpose of describing the embodiments of the present application. In addition, the structures shown in the drawings are often a part of the actual structure. In particular, the emphasis of each drawing needs to be different, and sometimes different scales are used.

[0031] As used in the present application, the singular forms "a", "an" and "the" include plural referents, the term "or" is generally used in the sense of "and / or", the term "several" is generally used in the sense of "at least one", the term "at least two" is generally used in the sense of "two or more", and in addition, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined as "first", "second", "third" can be explicitly or implicitly included one or at least two features, the term "proximal" is generally the end close to the operator, the term "distal" is generally the end close to the patient, "one end" and "the other end" and "proximal" and "distal" generally refer to two parts corresponding to each other, which not only includes the end point, the terms "mounting", "connection", "connection" should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication or interaction relationship between two elements. In addition, as used in the present application, a component is provided in another component, which generally only indicates that there is a connection, coupling, cooperation or transmission relationship between the two components, and the connection, coupling, cooperation or transmission between the two components can be direct or indirect through an intermediate component, and cannot be understood as indicating or implying the spatial positional relationship between the two components, i.e. one component can be in any orientation inside, outside, above, below or one side of another component, unless the content is otherwise explicitly indicated. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0032] The inventors have found that the holding voltage and failure current of the ESD device have problems.

[0033] Based on this, the core idea of the present application is to propose a new type of off-site trigger SCR device structure, which improves the holding voltage, failure current characteristics and performance per unit area of the device without increasing the occupied area, and realizes excellent area performance efficiency.

[0034] [Example One]

[0035] Specifically, refer to Figures 2-3 , which is a schematic diagram of the embodiment of the utility model. As Figure 2 indicated, a novel ectopic trigger SCR structure comprises:

[0036] The first conductive type base;

[0037] The first conductive type well region is arranged in the first conductive type base;

[0038] The second conductive type well region is arranged on one side of the first conductive type well region;

[0039] The first trigger region is arranged in the second conductive type well region;

[0040] The second trigger region is across the junction of the first conductive type base and the first conductive type well region, and the bottom of the second trigger region is further connected with a deep well region, wherein the first trigger region and the second trigger region and the deep well region are all of the second conductive type, and the first trigger region and the second trigger region are connected through the metal interconnection at the top.

[0041] If the first conductive type is P type and the second conductive type is N type. Therefore, the first conductive type semiconductor substrate can be doped with P type dopants, such as boron. But in other embodiments of the utility model, the carrier can be a hole, at this time, the first conductive type is N type, and the corresponding second conductive type is P type.

[0042] By introducing the first trigger region and the second trigger region and the deep well region, the avalanche breakdown current of the device is divided into two parts, which can flow out of the cathode through the basic structural unit in the second conductive type well region and the first conductive type well region respectively, wherein the current flowing out through the basic structural unit will flow out of the cathode through the shortest path, so it contributes relatively small to the SCR trigger, so the current through the first conductive type well region becomes the main trigger current, and the first trigger region and the second trigger region change the current direction through the metal interconnection, so that the right side part of the N type first conductive type well region and the P type second conductive type well region is turned on first.

[0043] It can be understood that the current is divided into two parts by the first trigger region and the second trigger region with interconnection to control the device trigger point and the trigger direction. Compared with the traditional SCR device structure, the voltage and current characteristics of the SCR device are improved, and the novel ectopic trigger SCR structure better maintains the voltage and failure current characteristics.

[0044] In one embodiment, the first conductive type substrate is a P-type substrate 101, the first conductive type well region is a P-type well region 103, and the second conductive type well region is a first N-type well region 102. A first N-type trigger region 107 is disposed in the first N-type well region 102, and a second N-type trigger region 110 is disposed at the junction of the P-type well region 103 and the P-type substrate 101. The bottom of the second N-type trigger region 110 is further connected to a second N-type well region 104, and one side of the second N-type well region 104 is further connected to the sidewall of the P-type well region 103.

[0045] It can be understood that the first N-type well region 102 is located inside the P-type substrate 101, the upper edge thereof is tangent to the upper edge of the P-type substrate 101, and the lower edge thereof is slightly higher than the lower edge of the P-type substrate 101. The P-type well region 103 and the second N-type well region 104 are located inside the P-type substrate 101, the upper edge thereof is tangent to the upper edge of the P-type substrate 101, and the lower edge thereof is slightly higher than the lower edge of the P-type substrate 101. The P-type well region 103 and the second N-type well region 104 are adjacent to each other, the P-type well region 103 is located on the left side of the second N-type well region 104, the right edge thereof is tangent to the left edge of the second N-type well region 104, and the P-type well region 103 is adjacent to the first N-type well region 102, the left edge thereof is tangent to the right edge of the first N-type well region 102.

[0046] In one embodiment, the corresponding basic structural units are formed in the first N-type well region 102 and the P-type well region 103 to constitute an SCR structure. An anode P-type region 106 is further disposed in the first N-type well region 102, one side of the anode P-type region 106 is connected to an anode N-type region 105, and the other side is spaced apart from the first N-type trigger region 107. A cathode N-type region 109 is further disposed in the P-type well region 103, one side of the cathode N-type region 109 is connected to a cathode P-type region 108, and the other side is spaced apart from the second N-type trigger region 110.

[0047] The anode N-type region 105, the anode P-type region 106, and the first N-type trigger region 107 are located inside the first N-type well region 102, the upper edge of each of the anode N-type region 105, the anode P-type region 106, and the first N-type trigger region 107 is tangent to the upper edge of the first N-type well region 102, and the lower edge of each of the anode N-type region 105, the anode P-type region 106, and the first N-type trigger region 107 is higher than the first N-type well region 102. The anode N-type region 105 is located on the left side of the anode P-type region 106, the right edge of the anode N-type region 105 is tangent to the left edge of the anode P-type region 106, the first N-type trigger region 107 is located on the right side of the anode P-type region 106, and the left edge thereof is slightly spaced apart from the right edge of the anode P-type region 106.

[0048] Specifically, the cathode P-type region 108 and the cathode N-type region 109 are located inside the P-type well region 103, the upper edge of the cathode P-type region 108 and the cathode N-type region 109 is tangent to the upper edge of the P-type well region 103, and the lower edge is higher than the lower edge of the P-type well region 103; wherein the cathode P-type region 108 is located on the left side of the cathode N-type region 109, and the right edge of the cathode P-type region 108 is tangent to the left edge of the cathode N-type region 109.

[0049] The second N-type trigger region 110 spans the junction of the P-type well region 103 and the second N-type well region 104, or in other words, the second N-type trigger region 110 spans the junction of the P-type well region 103 and the P-type substrate 101, is located inside the P-type well region 103 and the second N-type well region 104, and the upper edge is tangent to the upper edge of the P-type well region 103 and the second N-type well region 104, and the lower edge is higher than the lower edge of the P-type well region 103 and the second N-type well region 104; the second N-type trigger region 110 is located on the right side of the cathode N-type region 109, and the left edge is slightly spaced from the right edge of the cathode N-type region 109.

[0050] The exemplary further includes an oxide layer 111 disposed on the top of the P-type substrate 101. The oxide layer 111 is, for example, silicon oxide, which is located directly above the P-type substrate 101, and the lower edge is tangent to the upper edge of the P-type substrate 101.

[0051] Specifically, the anode N-type region 105 and the anode P-type region 106 are covered with an anode metal 112 on the top of the oxide layer 111, and the anode metal 112 is connected to the anode N-type region 105 and the anode P-type region 106 through the perforations on the oxide layer 111. The cathode N-type region 109 and the cathode P-type region 108 are covered with a first cathode metal 113 on the top of the oxide layer 111, and the first cathode metal 113 is connected to the cathode N-type region 109 and the cathode P-type region 108 through the perforations on the oxide layer 111. The oxide layer 111 is arranged with a second cathode metal 114, which is concave and surrounds part of the first cathode metal 113, and the second cathode metal 114 is covered on the top of the oxide layer 111 on both sides of the first N-type trigger region 107 and the second N-type trigger region 110, and the second cathode metal 114 is connected to the first N-type trigger region 107 and the second N-type trigger region 110 through the perforations on the oxide layer 111.

[0052] The anode metal 112, the first cathode metal 113 and the second cathode metal 114 are located above the oxide layer 111, with their lower edges tangent to the upper edge of the oxide layer 111. The anode metal 112 is located directly above the anode N-type region 105 and the anode P-type region 106, and is connected to the anode N-type region 105 and the anode P-type region 106 through perforations in the oxide layer 111; the first cathode metal 113 is located directly above the cathode P-type region 108 and the cathode N-type region 109, and is connected to the cathode P-type region 108 and the cathode N-type region 109 through perforations in the oxide layer 111; the second cathode metal 114 is in the shape of a "concave", and surrounds the first cathode metal 113, with its two sides located directly above the first N-type trigger region 107 and the second N-type trigger region 110, and connected to the first N-type trigger region 107 and the second N-type trigger region 110 through perforations in the oxide layer 111.

[0053] The anode N-type region 105 and the anode P-type region 106 are interconnected by the anode metal 112 to form the anode of the device, and the cathode P-type region 108 and the cathode N-type region 109 are interconnected by the first cathode metal 113 to form the cathode of the device.

[0054] As shown in Figure 3 , the current path of the new SCR device is different from that of the conventional SCR device. Compared with the conventional SCR device, the high current density region of the new SCR device is distributed in the internal region of the device body, rather than in the surface region as in the conventional SCR device. This not only helps to suppress the rapid PW high injection caused by positive feedback, but also helps to make it difficult for the subsequent current to concentrate in the local hot spot region on the silicon surface

[0055] In an embodiment, the basic structural unit in the well region can also be adjusted to other ion implantation regions to form an NPN structure, a PNP structure or a diode structure.

[0056]

Embodiment Two

[0057] Based on the same technical concept, the disclosure also provides another new SCR device structure with N-type doped semiconductor as substrate, as shown in Figure 4 , taking the N-type substrate 115 as the substrate, forming the P-type deep well region 116 after P-type doping in the substrate, and then manufacturing other structural parts of the new SCR device in the substrate.

[0058] Specifically, the P-type deep well region 116 is located inside the N-type substrate 115, the upper edge of which is tangent to the upper edge of the N-type substrate 115, and the lower edge of which is slightly higher than the lower edge of the N-type substrate 115. The first N-type well region 102 is located inside the P-type deep well region 116, the upper edge of which is tangent to the upper edge of the P-type deep well region 116, and the lower edge of which is slightly higher than the lower edge of the P-type deep well region 116. The P-type well region 103 and the second N-type well region 104 are located inside the P-type deep well region 116, the upper edge of which is tangent to the upper edge of the P-type deep well region 116, and the lower edge of which is slightly higher than the lower edge of the P-type deep well region 116; the P-type well region 103 and the second N-type well region 104 are adjacent, the P-type well region 103 is located on the left side of the second N-type well region 104, and the right edge of the P-type well region 103 is tangent to the left edge of the second N-type well region 104; the P-type well region 103 and the first N-type well region 102 are adjacent, and the left edge of the P-type well region 103 is tangent to the right edge of the first N-type well region 102. The remaining structure is the same as that of the P-type substrate novel ectopic trigger SCR device structure, and will not be described here.

[0059] The novel ectopic trigger SCR device structure provided by the utility model improves the maintaining voltage, failure current characteristics of the device, and the performance per unit area, and realizes excellent area performance efficiency without increasing the occupied area.

[0060] Compared with the traditional SCR device structure, the novel ectopic trigger SCR device structure provided by the utility model has a novel cathode metal structure and a novel trigger mode. Figure 3 As shown in the figure, the novel cathode metal structure and the novel trigger mode divide the avalanche breakdown current of the device into two parts, which flow out of the cathode through the P-type well region and the cathode N-type region respectively. Since the current passing through the cathode N-type region flows out of the cathode through the shortest path, its contribution to SCR triggering is relatively minimal. Therefore, the current passing through the P-type well region will become the main trigger current. The existence of the second cathode metal structure changes the direction of the current, so that the right side of the N / P well junction is turned on first.

[0061] Compared with the traditional SCR device, since the injection direction of the novel ectopic trigger SCR device is different, the high current density region is distributed in the region inside the main body of the device, instead of being distributed in the surface region like the traditional SCR device. This not only helps to suppress the rapid P-well high injection caused by positive feedback, but also helps to make it difficult for the subsequent current to concentrate in the local hot spot region on the silicon surface.

[0062] The device structure and the drawings are only one display and explanation of the novel ectopic trigger SCR device structure, any person skilled in the art can modify or change the above structure without departing from the spirit and scope of the novel, such as changing the SCR structure described above into PNP structure, NPN structure, diode structure, MOS structure and the like, or changing the number of stacked series or stacked packaging according to different application scenarios, and these structures should obviously be within the protection scope of the novel.

[0063] The above description is only a description of the preferred embodiments of the novel, and is not any limitation on the scope of the novel, any change or modification of the novel by the person skilled in the art according to the above disclosure is within the protection scope of the technical scheme of the novel.

Claims

1. A novel ESD triggered SCR structure, characterized in that, The application relates to a semiconductor device, comprising: a first conductive type substrate; a first conductive type well region arranged in the first conductive type substrate; a second conductive type well region arranged on one side of the first conductive type well region; a first trigger region arranged in the second conductive type well region; a second trigger region arranged across the boundary between the first conductive type substrate and the first conductive type well region, and a deep well region connected to the bottom of the second trigger region, wherein the first and second trigger regions and the deep well region are of the second conductive type, and the first and second trigger regions are connected by a metal interconnection at the top.

2. The novel Emitterless Triggered SCR structure of claim 1, wherein, The first conductive type substrate is a P-type substrate, the first conductive type well region is a P-type well region, and the second conductive type well region is a first N-type well region.

3. The novel Emitterless Triggered SCR structure of claim 2, wherein, A first N-type trigger region is arranged in the first N-type well region, and a second N-type trigger region is arranged at the boundary between the P-type well region and the P-type substrate.

4. The novel Emitterless Triggered SCR structure of claim 3, wherein, The bottom of the second N-type trigger region is further connected to a second N-type well region, and one side of the second N-type well region is connected to the sidewall of the P-type well region.

5. The novel Emitterless Triggered SCR structure as claimed in claim 3, wherein, An anode P-type region is further arranged in the first N-type well region, one side of the anode P-type region is connected to an anode N-type region, and the other side of the anode P-type region is arranged to be spaced apart from the first N-type trigger region.

6. The novel Emitterless Triggered SCR structure as claimed in claim 3, wherein, An oxide layer is further arranged on the top of the P-type substrate.

7. The novel Emitterless Triggered SCR structure as claimed in claim 5, wherein, An anode metal is correspondingly arranged on the oxide layer on the top of the anode N-type region and the anode P-type region, and the anode metal is connected to the anode N-type region and the anode P-type region through a through hole in the oxide layer.

8. The novel Emitterless Triggered SCR structure as claimed in claim 3, wherein, A cathode N-type region is further arranged in the P-type well region, one side of the cathode N-type region is connected to a cathode P-type region, and the other side of the cathode N-type region is arranged to be spaced apart from the second N-type trigger region.

9. The novel Emitterless Triggered SCR structure of claim 8, wherein, A first cathode metal is correspondingly arranged on the oxide layer on the top of the cathode N-type region and the cathode P-type region, and the first cathode metal is connected to the cathode N-type region and the cathode P-type region through a through hole in the oxide layer.

10. The novel Emitterless Triggered SCR structure of claim 9, wherein, A second cathode metal is arranged on the oxide layer, the second cathode metal is concave and surrounds part of the first cathode metal, two sides of the second cathode metal are arranged on the oxide layer on the top of the first N-type trigger region and the second N-type trigger region, and the second cathode metal is connected to the first N-type trigger region and the second N-type trigger region through a through hole in the oxide layer.

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