A SCR electrostatic protection device
By adopting alternating arrangement of N-type and P-type heavily doped active regions in the SCR electrostatic protection device, the annular structure of the N-type and P-type heavily doped active regions across the heavily doped active regions, and the arrangement of polysilicon above the well, the SCR device in the prior art is solved. The problem of the failure current decreases when increasing the maintenance voltage and reduces the turn-on voltage.
Patent Information
- Application Number
- CN202411441802.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-16
- Publication Date
- 2024-12-17
- Estimated Expiration
- 2044-10-16
AI Technical Summary
The problem of the reduction of failure current when existing SCR electrostatic protection devices increase the maintenance voltage.
By providing a plurality of first N-type heavily doped active regions and a plurality of first P-type heavily doped active regions in the N-type well, an alternately arranged in the second N-type heavily doped active region is arranged into a ring around the second N-type heavily doped active region, and A plurality of third N-type heavily doped active regions and a plurality of third P-type heavily doped active regions are arranged alternately in the P-type well to form a ring to increase the current The drain path is also provided at the adjacent N-type well and P-type well to be arranged across the heavily doped active region, and polysilicon is provided above the N-type well or P-type well to reduce the turn-on voltage.
While increasing the maintenance voltage, the current leakage path is added, which solves the problem of reduced failure current and reduces the turn-on voltage.
Smart Images
Figure CN118969792B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of electronic devices, and in particular to an SCR electrostatic protection device. Background Art
[0002] Electrostatic discharge refers to the electrical phenomenon that occurs when objects carrying static charges are transferred when they come into contact with each other, generating transient high voltage and high current. As semiconductors become smaller and smaller and the scale of integrated circuits continues to expand, semiconductor devices are becoming less resistant to ESD events.
[0003] SCR is the most robust device per unit area among basic ESD protection devices. It has the advantages of simple structure, no process restrictions during manufacturing, and no need for additional layers. However, its holding voltage Vh is low and latch-up effect is prone to occur. There are many ways to increase the holding voltage, such as increasing the size of the base region, using a stacked structure, and splitting the emitter. Among them, although splitting the device emitter can effectively increase the holding voltage, it will also greatly reduce the failure current. Summary of the invention
[0004] The object of the present invention is to provide an SCR electrostatic protection device to solve the problem of reducing device failure current in a method of increasing the SCR device maintenance voltage by splitting the device emitter.
[0005] To achieve the above object, the present invention adopts the following technical solution:
[0006] An SCR electrostatic protection device includes a substrate, an N-type well and a P-type well formed in the substrate, wherein the N-type well and the P-type well are adjacent to each other;
[0007] The N-type well is provided with a plurality of first N-type heavily doped active regions, a plurality of first P-type heavily doped active regions, and a second N-type heavily doped active region; the plurality of first N-type heavily doped active regions and the plurality of first P-type heavily doped active regions are alternately arranged in a ring around the second N-type heavily doped active region; the second N-type heavily doped active region is connected to the N-type well potential and is isolated from the first N-type heavily doped active region and the first P-type heavily doped active region by a first isolation structure; the plurality of first N-type heavily doped active regions, the plurality of first P-type heavily doped active regions, and the second N-type heavily doped active region are all connected to the anode; The P-type well is provided with a plurality of third N-type heavily doped active regions, a plurality of third P-type heavily doped active regions, and a second P-type heavily doped active region, and the plurality of third N-type heavily doped active regions and the plurality of third P-type heavily doped active regions are alternately arranged around the second P-type heavily doped active region to form a ring; the second P-type heavily doped active region is connected to the P-type well potential, and is isolated from the third N-type heavily doped active region and the third P-type heavily doped active region by a second isolation structure; the plurality of third N-type heavily doped active regions, the plurality of third P-type heavily doped active regions, and the second P-type heavily doped active region are all connected to the cathode;
[0008] A third isolation structure is used at the junction of the N-type well and the P-type well to isolate the first N-type heavily doped active area and the first P-type heavily doped active area in the N-type well from the third N-type heavily doped active area and the third P-type heavily doped active area in the P-type well.
[0009] Furthermore, a spanning heavily doped active region spanning the N-type well and the P-type well is provided adjacent to the N-type well and the P-type well, and the spanning heavily doped active region is a fourth N-type heavily doped active region or a fourth P-type heavily doped active region.
[0010] Furthermore, the SCR electrostatic protection device also includes polycrystalline silicon formed above the N-type well or the P-type well; when the polycrystalline silicon is formed above the N-type well, the spanning heavily doped active area is a P-type heavily doped active area, which is arranged on the spanning heavily doped active area and the upper surface between the first N-type heavily doped active area and the first P-type heavily doped active area adjacent to the spanning heavily doped active area, and is connected to the anode; when the polycrystalline silicon is formed above the P-well, the spanning heavily doped active area is an N-type heavily doped active area, which is arranged on the spanning heavily doped active area and the upper surface between the third N-type heavily doped active area and the third P-type heavily doped active area adjacent to the spanning heavily doped active area, and is connected to the cathode.
[0011] Furthermore, the substrate material is silicon.
[0012] Furthermore, the first isolation structure, the second isolation structure, and the third isolation structure are all shallow trench isolation structures or local field oxygen isolation structures.
[0013] Furthermore, the N-type well and the P-type well are high-voltage wells or low-voltage wells.
[0014] Furthermore, a fourth isolation structure is formed in the N-type well, and the fourth isolation structure extends outwardly into the substrate away from one end of the first N-type heavily doped active region or the first P-type heavily doped active region, and together with the third isolation structure, surrounds the multiple first N-type heavily doped active regions, the multiple first P-type heavily doped active regions, and the second N-type heavily doped active region; a fifth isolation structure is also formed in the P-type well, and the fifth isolation structure extends outwardly into the substrate away from one end of the third N-type heavily doped active region or the third P-type heavily doped active region, and together with the third isolation structure, surrounds the multiple third N-type heavily doped active regions, the multiple third P-type heavily doped active regions, and the second P-type heavily doped active region.
[0015] The present invention provides an SCR electrostatic protection device, which uses a plurality of first N-type heavily doped active areas and a plurality of first P-type heavily doped active areas in an N-type well to alternately arrange the active areas around the second N-type heavily doped active area to form a ring, and cooperates with a plurality of third N-type heavily doped active areas and a plurality of third P-type heavily doped active areas used in a P-type well to alternately arrange the active areas around the second P-type heavily doped active area to form a ring structure, so that the device can obtain more current discharge paths while increasing the holding voltage, thereby solving the problem of reducing the device failure current in the existing method of increasing the holding voltage of the SCR device by splitting the device emitter. In addition, by arranging a cross-over heavily doped active area at the junction of the N-type well and the P-type well, and arranging polysilicon in the N-type well or the P-type well, the turn-on voltage of the SCR electrostatic protection device is reduced. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 It is a cross-sectional structure diagram and an equivalent circuit diagram of an existing SCR electrostatic protection device;
[0017] Figure 2 It is a top view schematic diagram of an existing SCR electrostatic protection device;
[0018] Figure 3 It is a top view schematic diagram of the emitter segmentation of the existing SCR electrostatic protection device;
[0019] Figure 4 A schematic cross-sectional structure diagram of the SCR electrostatic protection device provided in Example 1;
[0020] Figure 5 An equivalent circuit diagram of the SCR electrostatic protection device provided in Example 1;
[0021] Figure 6 A schematic top view showing the emitter segmentation of the SCR electrostatic protection device provided in Example 1;
[0022] Figure 7 A schematic cross-sectional structure diagram of an SCR electrostatic protection device provided in Example 2, wherein the heavily doped active region is an N-type heavily doped active region;
[0023] Figure 8 A schematic diagram of emitter segmentation of an SCR electrostatic protection device provided in Example 2, wherein the heavily doped active region is an N-type heavily doped active region;
[0024] Fig. 9 A schematic cross-sectional structure diagram of an SCR electrostatic protection device provided in Example 2, wherein the heavily doped active region is a P-type heavily doped active region;
[0025] Fig.10 A schematic diagram of emitter segmentation of an SCR electrostatic protection device provided in Example 2, wherein the heavily doped active region is a P-type heavily doped active region;
[0026] Fig.11 A schematic cross-sectional structure diagram of an SCR electrostatic protection device in which polysilicon is formed on a P-type well provided in Example 3;
[0027] Fig.12 A schematic top view of the emitter segmentation of the SCR electrostatic protection device provided in Example 3, in which polysilicon is formed on a P-type well;
[0028] Fig.13 A schematic cross-sectional structure diagram of an SCR electrostatic protection device in which polysilicon is formed on an N-type well provided in Example 3;
[0029] Fig.14 A schematic top view of the emitter segmentation of the SCR electrostatic protection device provided in Example 3, in which polysilicon is formed on an N-type well;
[0030] Figure numerals: 1 is the first current path, 2 is the second current path, 3 is the third current path, 4 is the fourth current path, and 5 is the fifth current path; 100 is the substrate, 101 is the N-type well, 102 is the P-type well, 103 is the first STI isolation region, 104 is the first N+ doped active region, 105 is the first P+ doped active region, 106 is the second N+ doped active region, 107 is the second P+ doped active region, 108 is the second STI isolation region, 109 is the third STI isolation region, 110 is the fourth STI isolation region, and 111 is the fifth STI isolation region; 203 is the first isolation structure, 204 is the third isolation structure, 205 is the second isolation structure, 206 is the second P-type heavily doped active region, 207 is the second N-type heavily doped active region, 208 is the cross-heavy doped active region, 209 is polysilicon, 210 is the fourth isolation structure, and 211 is the fifth isolation structure. DETAILED DESCRIPTION
[0031] Figure 1 The following is a cross-sectional structural diagram and an equivalent circuit diagram of an existing SCR electrostatic protection device. Figure 2 FIG. 1 is a top view schematic diagram of an existing SCR electrostatic protection device. Figure 1-Figure 2As shown, the substrate 100 is a P-type substrate. An N-type well 101 and a P-type well 102 are formed adjacent to each other in the substrate 100 , and the upper surface of the N-type well 101 is flush with the upper surface of the P-type well 102 . The N-type well 101 is provided with a first STI isolation region 103, a first N+ doped active region 104, a second STI isolation region 108, and a first P+ doped active region 105 from left to right; the P-type well 102 is provided with a second N+ doped active region 106, a third STI isolation region 109, a second P+ doped active region 107, and a fourth STI isolation region 110 from left to right; a fifth STI isolation region 111 is provided at the junction of the N-type well 101 and the P-type well 102; the end of the first STI isolation region 103 away from the first N+ doped active region 104 extends downward to the left substrate 100, and the end of the fourth STI isolation region 110 away from the second P+ doped active region 107 extends downward to the right P-type well 102. The first N+ doped active region 104 and the first P+ doped active region 105 are connected to the anode, and the second N+ doped active region 106 and the second P+ doped active region 107 are connected to the cathode.
[0032] The N-type well 101, the P-type well 102 and the second N+ doped active region 106 constitute a parasitic NPN transistor, and the first P+ doped active region 105, the N-type well 101 and the P-type well 102 constitute a parasitic PNP transistor. Figure 1 From the equivalent circuit given in , it can be seen that the equivalent resistance of the N-type well 101 is R_nwell, and the equivalent resistance of the P-type well 102 is R_pwell. When the anode suffers an ESD event, a large amount of current enters from the anode, and the anode voltage gradually increases, causing avalanche breakdown in the N-type well 101 and the P-type well 102. The current flows through R_nwell and R_pwell to generate a voltage drop, causing the parasitic NPN and PNP to turn on and discharge the large current.
[0033] In the existing SCR electrostatic protection device, if the ESD maintenance voltage is lower than the normal working voltage of the protected circuit in a high voltage working environment, the ESD device cannot be normally closed under the normal working voltage after the ESD event ends, affecting the normal operation of the circuit.
[0034] Figure 3 FIG. 1 is a top view schematic diagram of an existing SCR electrostatic protection device after the emitter is segmented. Figure 3 It can be seen that although the existing emitter segmentation method can improve the above-mentioned SCR device maintenance voltage, it will cause the problem of reduced device failure current.
[0035] Therefore, the present invention proposes an SCR electrostatic protection device, which increases the holding voltage by alternately arranging the split NPN tube and PNP tube emitters with N-type heavy doping and P-type heavy doping and forming a ring. At the same time, the ring emitter is used to obtain more current paths, thereby suppressing the reduction of the device failure current.
[0036] In order to make the purpose and features of the present invention more obvious and easy to understand, the present invention is described in detail below with reference to the accompanying drawings and embodiments.
[0037] Embodiment 1, as Figure 4 and Figure 6 As shown, an SCR electrostatic protection device provided in this embodiment includes a substrate 100. The substrate 100 is made of silicon. An adjacent N-type well 101 and a P-type well 102 are formed in the substrate 100, and the upper surfaces of the two are flush.
[0038] The N-type well 101 is provided with a plurality of first N-type heavily doped active regions, a plurality of first P-type heavily doped active regions, and a second N-type heavily doped active region 207; the plurality of first N-type heavily doped active regions and the plurality of first P-type heavily doped active regions are alternately arranged in a ring around the second N-type heavily doped active region 207; the second N-type heavily doped active region 207 is connected to the potential of the N-type well 101, and is isolated from the first N-type heavily doped active region and the first P-type heavily doped active region by the first isolation structure 203.
[0039] The P-type well 102 is provided with a plurality of third N-type heavily doped active regions, a plurality of third P-type heavily doped active regions, and a second P-type heavily doped active region 206. The plurality of third N-type heavily doped active regions and the plurality of third P-type heavily doped active regions are alternately arranged in a ring around the second P-type heavily doped active region 206. The second P-type heavily doped active region 206 is connected to the potential of the P-type well 102, and is isolated from the third N-type heavily doped active region and the third P-type heavily doped active region by a second isolation structure 205.
[0040] A third isolation structure 204 is used at the junction of the N-type well 101 and the P-type well 102 to isolate the first N-type heavily doped active region and the first P-type heavily doped active region in the N-type well 101 from the third N-type heavily doped active region and the third P-type heavily doped active region in the P-type well 102 .
[0041] The fourth isolation structure 210 extends outwardly into the substrate 100 from one end away from the first N-type heavily doped active region or the first P-type heavily doped active region, and the fourth isolation structure 210 and the third isolation structure 204 jointly surround the plurality of first N-type heavily doped active regions, the plurality of first P-type heavily doped active regions, and the second N-type heavily doped active region 207. The fifth isolation structure 211 extends outwardly into the substrate 100 from one end away from the third N-type heavily doped active region or the third P-type heavily doped active region, and the fifth isolation structure 211 and the third isolation structure 204 jointly surround the plurality of third N-type heavily doped active regions, the plurality of third P-type heavily doped active regions, and the second P-type heavily doped active region 206.
[0042] The first isolation structure 203, the second isolation structure 205, and the third isolation structure 204 are all shallow trench isolation structures or local field oxygen isolation structures, and the trench isolation structure is preferred in this embodiment. When in use, multiple first P-type heavily doped active regions, N-type well 101 and P-type well 102 form a PNP tube, multiple first P-type heavily doped active regions are used as emitters, N-type well 101 is used as a base, and P-type well 102 is used as a collector. Multiple third N-type heavily doped active regions, P-type well 102 and N-type well 101 form an NPN tube, multiple third N-type heavily doped active regions are used as emitters, P-type well 102 is used as a base, and N-type well 101 is used as a collector. The multiple first N-type heavily doped active regions, the multiple first P-type heavily doped active regions, and the second N-type heavily doped active region 207 in the N-type well 101 are all connected to the anode, and the multiple third N-type heavily doped active regions, the multiple third P-type heavily doped active regions, and the second P-type heavily doped active region 206 in the P-type well 102 are all connected to the cathode.
[0043] The equivalent circuit of the SCR electrostatic protection device of this embodiment is shown in Figure 5 When a large ESD current is injected from the anode, the anode voltage gradually increases until it is higher than the breakdown voltage of the N-type well 101 and the P-type well 102, and an avalanche breakdown occurs between the N-type well 101 and the P-type well 102, generating a large amount of current. The current flowing through the N-type well 101 generates a voltage drop through the resistance of the N-type well 101, so that the PN junction formed between the multiple first P-type heavily doped active regions in the N-type well 101 and the N-type well 101 is turned on, thereby turning on the PNP tube; the current flowing through the P-type well 102 generates a voltage drop through the resistance of the P-type well 102, so that the PN junction formed between the multiple third N-type heavily doped active regions in the P-type well 102 and the P-type well 102 is turned on, thereby turning on the NPN tube. The collector current of the NPN tube provides the base current for the PNP tube, and the collector current of the PNP tube provides the base current for the NPN tube. The SCR path is formed to discharge the ESD current.
[0044] In this embodiment, the N-type well 101 uses a plurality of first N-type heavily doped active areas and a plurality of first P-type heavily doped active areas to alternately arrange in a ring around the second N-type heavily doped active area 207, and the P-type well 102 uses a plurality of third N-type heavily doped active areas and a plurality of third P-type heavily doped active areas to alternately arrange in a ring around the second P-type heavily doped active area 206, so that the device can obtain more discharge current paths while improving the holding voltage, thereby improving the failure current of the device. The added partial current path is shown in FIG. Figure 6 , by the Figure 6 It can be seen that Figure 1 Compared with the existing SCR electrostatic protection device given above, the SCR electrostatic protection device of this embodiment has more circuit paths. Figure 6 Only the first current path 1, the second current path 2, the third current path 3, the fourth current path 4, and the fifth current path 5 are given for illustration.
[0045] Embodiment 2: A SCR electrostatic protection device provided in this embodiment is based on the structure of the SCR electrostatic protection device provided in Embodiment 1. By providing a crossover heavily doped active region 208 that crosses the N-type well 101 and the P-type well 102 at the junction of the N-type well 101 and the P-type well 102, the turn-on voltage of the SCR electrostatic protection device is reduced. The crossover heavily doped active region 208 is an N-type heavily doped active region or a P-type heavily doped active region. The structure in which the crossover heavily doped active region 208 is an N-type heavily doped active region is as shown in FIG. Figure 7-Figure 8 As shown, the structure across the heavily doped active region 208 is a P-type heavily doped active region as shown in FIG9- Fig.10 shown.
[0046] In the case where the heavily doped active region 208 across the N-type heavily doped active region: when a large ESD current is injected from the anode, the anode voltage gradually increases until it is higher than the breakdown voltage across the heavily doped active region 208 and the P-type well 102, and an avalanche breakdown occurs between the heavily doped active region 208 across the P-type well 102, generating a large amount of current. The current flowing through the P-type well 102 generates a voltage drop through the resistance of the P-type well 102, so that the PN junction formed between the multiple third N-type heavily doped active regions in the P-type well 102 and the P-type well 102 is turned on, thereby turning on the NPN tube; the current flowing through the N-type well 101 generates a voltage drop through the resistance of the N-type well 101, so that the PN junction formed between the multiple first P-type heavily doped active regions in the N-type well 101 and the N-type well 101 is turned on, thereby turning on the PNP. The collector current of the NPN tube provides the base current for the PNP, and the collector current of the PNP provides the base current for the NPN, and the SCR path is formed to discharge the ESD current.
[0047] In the case where the heavily doped active region 208 across the P-type heavily doped active region: when a large ESD current is injected from the anode, the anode voltage gradually increases until it is higher than the breakdown voltage across the heavily doped active region 208 and the N-type well 101, and an avalanche breakdown occurs between the heavily doped active region 208 across the N-type well 101, generating a large amount of current. The current flowing through the N-type well 101 generates a voltage drop through the resistance of the N-type well 101, so that the PN junction formed between the multiple first P-type heavily doped active regions in the N-type well 101 and the N-type well 101 is turned on, thereby turning on the PNP; the current flowing through the P-type well 102 generates a voltage drop through the resistance of the P-type well 102, so that the PN junction formed between the multiple third N-type heavily doped active regions in the P-type well 102 and the P-type well 102 is turned on, thereby turning on the NPN tube. The collector current of the NPN tube provides the base current for the PNP, and the collector current of the PNP provides the base current for the NPN, and the SCR path is formed to discharge the ESD current.
[0048] Embodiment 3: This embodiment provides an SCR electrostatic protection device. Based on the SCR electrostatic protection device provided in Embodiment 2, polysilicon 209 is disposed above the N-type well 101 or the P-type well 102 .
[0049] like Figure 13-14 As shown, when polysilicon 209 is formed above the N-type well 101, the cross-over heavily doped active region 208 is a P-type heavily doped active region, which is arranged on the cross-over heavily doped active region 208 and the upper surface between the multiple first N-type heavily doped active regions and the multiple first P-type heavily doped active regions adjacent to the cross-over heavily doped active region 208, and is connected to the anode. Through the arrangement of polysilicon 209, a PMOS structure can be formed in the N-type well 101, so that the turn-on voltage of the SCR electrostatic protection device is further reduced. When a large ESD current is injected from the anode, the anode voltage gradually increases until it is higher than the breakdown voltage of the MOS tube composed of the cross-over heavily doped active region 208, polysilicon 209, the N-type well 101 and the multiple first P-type heavily doped active regions in the N-type well 101, and the MOS tube breaks down and generates a large amount of current. The current flowing through the N-type well 101 generates a voltage drop through the resistor of the N-type well 101, so that the PN junction formed between the multiple first P-type heavily doped active regions in the N-type well 101 and the N-type well 101 is turned on, thereby turning on the PNP; the current flowing through the P-type well 102 generates a voltage drop through the resistor of the P-type well 102, so that the PN junction formed between the multiple third N-type heavily doped active regions in the P-type well 102 and the P-type well 102 is turned on, thereby turning on the NPN tube. The collector current of the NPN tube provides the base current for the PNP, and the collector current of the PNP provides the base current for the NPN, and the SCR path is formed to discharge the ESD current.
[0050] like Figure 11-Figure 12As shown, when polysilicon 209 is formed above the P-type well 102, the cross-over heavily doped active region 208 is an N-type heavily doped active region, which is arranged on the cross-over heavily doped active region 208 and the upper surface between the third N-type heavily doped active region and the third P-type heavily doped active region adjacent to the cross-over heavily doped active region 208, and is connected to the cathode. Through the arrangement of polysilicon 209, an NMOS structure can be formed in the P-type well 102, so that the turn-on voltage of the SCR electrostatic protection device is further reduced. When a large ESD current is injected from the anode, the anode voltage gradually increases until it is higher than the breakdown voltage of the MOS tube composed of the cross-over heavily doped active region 208, polysilicon 209, the P-type well 102, and multiple third N-type heavily doped active regions in the P-type well 102, and the MOS tube breaks down, generating a large amount of current. The current flowing through the P-type well 102 generates a voltage drop through the resistor of the P-type well 102, so that the PN junction formed between the third N-type heavily doped active regions in the P-type well 102 and the P-type well 102 is turned on, thereby turning on the NPN tube; the current flowing through the N-type well 101 generates a voltage drop through the resistor of the N-type well 101, so that the PN junction formed between the first P-type heavily doped active regions in the N-type well 101 and the N-type well 101 is turned on, thereby turning on the PNP. The collector current of the NPN tube provides a base current for the PNP, and the collector current of the PNP provides a base current for the NPN, and the SCR path is formed to discharge the ESD current.
[0051] It should be noted that all structural equivalent circuits given in Examples 1 to 3 are the same, so the structural equivalent circuit diagrams are referred to in Figure 5 That's it.
[0052] In summary, the present invention provides an SCR electrostatic protection device, which uses a plurality of first N-type heavily doped active areas and a plurality of first P-type heavily doped active areas in the N-type well 101 to alternately arrange the second N-type heavily doped active area 207 into a ring, and cooperates with a plurality of third N-type heavily doped active areas and a plurality of third P-type heavily doped active areas used in the P-type well 102 to alternately arrange the second P-type heavily doped active area 206 to form a ring structure, so that the device can obtain more paths for discharging current while increasing the holding voltage, thereby solving the problem of reducing the device failure current in the existing method of increasing the holding voltage of the SCR device by splitting the device emitter. In addition, by arranging a cross-over heavily doped active area 208 at the junction of the N-type well 101 and the P-type well 102, and arranging polysilicon 209 in the N-type well 101 or the P-type well 102, the turn-on voltage of the SCR electrostatic protection device is further reduced.
[0053] It is to be understood that the present invention is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are within the scope of protection of the present invention.
Claims
1. An SCR electrostatic protection device, comprising a substrate, an N-type well and a P-type well formed in the substrate, wherein the N-type well and the P-type well are adjacent to each other, characterized in that: The N-type well is provided with a plurality of first N-type heavily doped active regions, a plurality of first P-type heavily doped active regions, and a second N-type heavily doped active region; the plurality of first N-type heavily doped active regions and the plurality of first P-type heavily doped active regions are alternately arranged in a ring around the second N-type heavily doped active region; the second N-type heavily doped active region is connected to the N-type well potential and is isolated from the first N-type heavily doped active region and the first P-type heavily doped active region by a first isolation structure; the plurality of first N-type heavily doped active regions, the plurality of first P-type heavily doped active regions, and the second N-type heavily doped active region are all connected to the anode; The P-type well is provided with a plurality of third N-type heavily doped active regions, a plurality of third P-type heavily doped active regions, and a second P-type heavily doped active region, and the plurality of third N-type heavily doped active regions and the plurality of third P-type heavily doped active regions are alternately arranged around the second P-type heavily doped active region to form a ring; the second P-type heavily doped active region is connected to the P-type well potential, and is isolated from the third N-type heavily doped active region and the third P-type heavily doped active region by a second isolation structure; the plurality of third N-type heavily doped active regions, the plurality of third P-type heavily doped active regions, and the second P-type heavily doped active region are all connected to the cathode; A third isolation structure is used at the junction of the N-type well and the P-type well to isolate multiple first N-type heavily doped active areas and multiple first P-type heavily doped active areas in the N-type well from multiple third N-type heavily doped active areas and multiple third P-type heavily doped active areas in the P-type well.
2. The SCR electrostatic protection device according to claim 1, characterized in that: A crossover heavily doped active region spanning the N-type well and the P-type well is provided adjacent to the N-type well and the P-type well. The crossover heavily doped active region is a fourth N-type heavily doped active region or a fourth P-type heavily doped active region.
3. The SCR electrostatic protection device according to claim 2, characterized in that: The SCR electrostatic protection device also includes polysilicon formed above the N-type well or the P-type well; when the polysilicon is formed above the N-type well, the cross-over heavily doped active area is a P-type heavily doped active area, which is arranged on the cross-over heavily doped active area and the upper surface between the first N-type heavily doped active area and the first P-type heavily doped active area adjacent to the cross-over heavily doped active area, and is connected to the anode; when the polysilicon is formed above the P-well, the cross-over heavily doped active area is an N-type heavily doped active area, which is arranged on the cross-over heavily doped active area and the upper surface between the third N-type heavily doped active area and the third P-type heavily doped active area adjacent to the cross-over heavily doped active area, and is connected to the cathode.
4. The SCR electrostatic protection device according to claim 1, characterized in that: The substrate material is silicon.
5. The SCR electrostatic protection device according to claim 1, characterized in that: The first isolation structure, the second isolation structure, and the third isolation structure are all shallow trench isolation structures or local field oxygen isolation structures.
6. The SCR electrostatic protection device according to claim 1, characterized in that: The N-type well and the P-type well are high-voltage wells or low-voltage wells.
7. An SCR electrostatic protection device according to any one of claims 1 to 6, characterized in that: A fourth isolation structure is also formed in the N-type well, and the fourth isolation structure extends outwardly into the substrate away from one end of the first N-type heavily doped active region or the first P-type heavily doped active region, and together with the third isolation structure, surrounds multiple first N-type heavily doped active regions, multiple first P-type heavily doped active regions, and the second N-type heavily doped active region; a fifth isolation structure is also formed in the P-type well, and the fifth isolation structure extends outwardly into the substrate away from one end of the third N-type heavily doped active region or the third P-type heavily doped active region, and together with the third isolation structure, surrounds multiple third N-type heavily doped active regions, multiple third P-type heavily doped active regions, and the second P-type heavily doped active region.