SCR structure
By setting the first P-type heavily doped region in the first N-type heavily doped region in the SCR structure and dividing it into multiple interval-set blocks, the problem of low maintenance voltage in the SCR structure is solved, and a higher maintenance voltage and a lower auxiliary trigger voltage are achieved.
Patent Information
- Application Number
- CN202411729907.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-28
- Publication Date
- 2025-03-14
AI Technical Summary
The low maintenance voltage of the existing SCR structures leads to a risk of latch up when applied to the corresponding voltage port.
By setting the first P-type heavily doped region in the first N-type heavily doped region in the SCR structure and dividing the first P-type heavily doped region into a plurality of spaced blocks, the sides of the plurality of first P-type heavily doped regions are surrounded by the first N-type heavily doped region, thereby increasing the ion implantation concentration of the PNP transistor base region.
The maintenance voltage of the SCR structure is effectively increased, the auxiliary trigger voltage of the NMOS transistor to the SCR structure is reduced, and the current amplification factor β of the NPN transistor is reduced, thereby further increasing the maintenance voltage.
Smart Images
Figure CN119630067A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of semiconductor device manufacturing, and in particular to an SCR structure. Background Art
[0002] With the continuous development of semiconductor processes and integrated circuit technology, device feature sizes are shrinking, and the extremely thin gate oxide layer of transistors is more susceptible to electrostatic damage. In the process of integrated circuit manufacturing, transportation, packaging and application, it is easy to be affected by this. ESD damage can be divided into hard damage and soft damage. Hard damage causes the circuit performance to fail to meet the requirements or functional failure, and the circuit is judged as unqualified; soft damage does not cause functional failure of the circuit, but only the circuit parameters are offset, which can meet the use of some systems, but it will affect the long-term reliability of the device. ESD damage has become an important issue that must be considered in integrated circuit design.
[0003] Silicon controlled rectifier (SCR), also known as thyristor, is widely used in power devices because it can switch between high resistance and low resistance and can be used as a power switch. However, it is also a very effective ESD protection device. Due to its low holding voltage, it can withstand very high ESD current, has strong static discharge capability, small area, and flexible process implementation. Therefore, it has become the first choice for high-reliability circuit protection devices. When electrostatic shock occurs, the SCR structure conducts a large amount of current and quickly discharges excess charge to prevent damage to the protected device. However, due to the low holding voltage of the SCR structure, there is a risk of latch-up when applied to the corresponding voltage port. Summary of the invention
[0004] In view of the above-mentioned shortcomings of the prior art, an object of the present invention is to provide an SCR structure for solving the problem that the SCR structure in the prior art has a low sustaining voltage, resulting in a risk of latch-up when applied to a corresponding voltage port.
[0005] To achieve the above objectives and other related objectives, the present invention provides an SCR structure, the SCR structure comprising:
[0006] P-type substrate;
[0007] An N-type well region located on the P-type substrate;
[0008] A P-type well region located inside the N-type well region; wherein the P-type well region extends from a portion of the upper surface of the N-type well region toward the inside thereof;
[0009] A first N-type heavily doped region extending from the upper surface of the N-type well region to the interior thereof;
[0010] a plurality of mutually separated first P-type heavily doped regions located in the first N-type heavily doped region and extending inwardly from an upper surface of the first N-type heavily doped region;
[0011] A second N-type heavily doped region and a second P-type heavily doped region separated from each other extending from the upper surface of the P-type well region to the inside thereof;
[0012] The first N-type heavily doped region and the second N-type heavily doped region are spaced apart, and a gate is formed on the surface of the P-type well region in the space;
[0013] The first N-type heavily doped region is configured as an anode of the SCR structure, and the gate, the second N-type heavily doped region, and the second P-type heavily doped region are collectively configured as a cathode of the SCR structure.
[0014] Optionally, the first N-type heavily doped region, the second N-type heavily doped region and the second P-type heavily doped region are arranged in sequence along a first direction; a plurality of mutually separated first P-type heavily doped regions are arranged along a second direction; and the first direction is perpendicular to the second direction.
[0015] Optionally, an isolation structure is provided between the second N-type heavily doped region and the second P-type heavily doped region.
[0016] Optionally, part of the first N-type heavily doped region extends to the P-type well region.
[0017] Optionally, the doping depth of the first N-type heavily doped region is the same as the doping depth of the first P-type heavily doped region; or the doping depth of the first N-type heavily doped region is different from the doping depth of the first P-type heavily doped region.
[0018] Optionally, one side of at least one of the P-type heavily doped regions overlaps with a side of the first N-type heavily doped region away from the second N-type heavily doped region.
[0019] Optionally, one side of at least one of the P-type heavily doped regions overlaps with a side of the first N-type heavily doped region close to the second N-type heavily doped region.
[0020] Optionally, all of the first P-type heavily doped regions have the same shape and size and are arranged at equal intervals.
[0021] Furthermore, a cross-sectional shape of the first P-type heavily doped region is a rectangle.
[0022] Furthermore, the length of the first P-type heavily doped regions along their arrangement direction is 2 to 3 times the spacing distance between two adjacent first P-type heavily doped regions.
[0023] Optionally, the doping concentration of the first N-type heavily doped region is at least one order of magnitude greater than the doping concentration of the N-type well region.
[0024] As described above, the SCR structure of the present invention effectively improves the ion implantation concentration of the base region of the PNP transistor in the SCR structure by setting the first P-type heavily doped region in the first N-type heavily doped region, that is, the two are in a state of contact with each other, and at the same time divides the first P-type heavily doped region into a plurality of first P-type heavily doped regions arranged at intervals, so that the sides of the plurality of first P-type heavily doped regions are surrounded by the first N-type heavily doped region, thereby effectively improving the holding voltage of the SCR structure; in addition, it can also effectively reduce the auxiliary trigger voltage of the NMOS transistor to the SCR structure; finally, the current amplification factor β of the NPN transistor composed of the first P-type heavily doped region and the first N-type heavily doped regions on its left and right sides is reduced, thereby further improving the holding voltage of the SCR structure. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1 A schematic cross-sectional view of an exemplary SCR structure is shown.
[0026] Figure 2 Display as Figure 1 Schematic diagram of the top view structure.
[0027] Figure 3 , Figure 4 , Figure 5 and Fig. 9 Shown is a schematic cross-sectional structure diagram of the SCR structure of the present invention.
[0028] Figure 6 , Figure 7 , Figure 8 and Fig.10 Shown is a schematic top view of the SCR structure of the present invention.
[0029] Figures 11 to 17 Shown are schematic top-view structures of several examples of the first P-type heavily doped region in the SCR structure of the present invention.
[0030] Component number description
[0031] 10 P-type substrate
[0032] 11 N-type well region
[0033] 110 The first N-type heavily doped region
[0034] 111 The first P-type heavily doped region
[0035] 12 P-type well region
[0036] 120 Second N-type heavily doped region
[0037] 121 Second P-type heavily doped region
[0038] 13. Gate
[0039] 14 Device anode
[0040] 15 Device cathode
[0041] 16 Shallow Trench Isolation
[0042] 17 Interval
[0043] 20 P-type substrate
[0044] 21 N-type well region
[0045] 210 The first N-type heavily doped region
[0046] 211 The first P-type heavily doped region
[0047] 22 P-type well region
[0048] 220 Second N-type heavily doped region
[0049] 221 Second P-type heavily doped region
[0050] 222 The third N-type heavily doped region
[0051] 23 Gate
[0052] 24 Device anode
[0053] 25 Device cathode
[0054] 26 Isolation Structure DETAILED DESCRIPTION
[0055] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention.
[0056] See also Figures 1 to 17 It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and the illustrations only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.
[0057] As described in the background art, the SCR structure has a very low holding voltage, so it can withstand very high ESD currents. However, due to the low holding voltage of the SCR structure, there is a risk of latch-up when it is applied to the corresponding voltage port. Figure 1 and Figure 2 As shown, an exemplary SCR structure is shown, which includes: a P-type substrate 20, an N-type well region 21 formed on the P-type substrate 20; a P-type well region 22 formed in a preset partial area on the surface of the N-type well region 21, and the depth of the P-type well region 22 is less than the depth of the N-type well region 21; a first N-type heavily doped region 210 and a first P-type heavily doped region 211 formed on the upper surface of the N-type well region 21 and contacting each other and arranged together; a second N-type heavily doped region 220 and a second P-type heavily doped region 221 formed on the upper surface of the P-type well 22 and arranged in sequence; and a second N-type heavily doped region 220 and a second P-type heavily doped region 221 formed on the upper surface of the P-type well 22 and arranged in sequence. The third N-type heavily doped region 222 at the junction, wherein a portion of the third N-type heavily doped region 222 is formed on the surface of the N-type well region 21 and is spaced apart from the first P-type heavily doped region 211, and another portion is formed on the surface of the P-type well region 22; the third N-type heavily doped region 222 is spaced apart from the second N-type heavily doped region 220, and an NMOS transistor gate 23 is formed on the surface of the P-type well region 22 in the space; the first N-type heavily doped region 210 is electrically connected to the device anode 24, and the gate 23, the second N-type heavily doped region 220 and the second P-type heavily doped region 221 are connected to the device cathode 25. The advantage of the SCR-based structure is that it can obtain higher current capacity and withstand voltage, but the disadvantage is that the maintenance voltage is relatively low.
[0058] Based on this, Figures 3 to 8 As shown, this embodiment provides an SCR structure, which includes: a P-type substrate 10; an N-type well region 11 located on the P-type substrate 10; a P-type well region 12 located inside the N-type well region 11, and the P-type well region 12 extends from a portion of the upper surface of the N-type well region 11 to the inside thereof; a first N-type heavily doped region 110 extending from the upper surface of the N-type well region 11 to the inside thereof; a plurality of mutually separated first P-type heavily doped regions 111 located in the first N-type heavily doped region 110 and extending inward from the upper surface of the first N-type heavily doped region 110; a second N-type heavily doped region 120 and a second P-type heavily doped region 121 extending from the upper surface of the P-type well region 12 to the inside thereof and mutually separated along a first direction OX; the first N-type heavily doped region 110 and the second N-type heavily doped region 120 are arranged at intervals, and a gate 13 is formed on the surface of the P-type well region 12 at the interval;
[0059] The first N-type heavily doped region 110 is configured as the anode 14 of the SCR structure, and the gate 13 , the second N-type heavily doped region 120 , and the second P-type heavily doped region 121 are collectively configured as the cathode 15 of the SCR structure.
[0060] like Figure 6 As shown, a plurality of the first P-type heavily doped regions 111 are sequentially arranged along a second direction OY on a horizontal plane, and the first direction OX is perpendicular to the second direction OY; wherein all the first P-type heavily doped regions 111 are arranged at intervals along the second direction OY, so that the first N-type heavily doped regions 110 are connected as a whole through the interval 17 between two adjacent first P-type heavily doped regions 111 (such as Fig.11 shown).
[0061] It should be noted that, for ease of understanding and description, the SCR structure is described in the present embodiment in an OXYZ three-dimensional rectangular coordinate system. Figures 3 to 5 The cross-sectional structure is the cross-sectional structure of the XOZ plane, that is, the vertical plane in space, such as Figures 6 to 8 The top-view structure is the top-view structure of the XOY plane, that is, the horizontal plane.
[0062] As an example, the first N-type heavily doped region 110 , the second N-type heavily doped region 120 , and the second P-type heavily doped region 121 are sequentially arranged along the first direction OX; a plurality of mutually separated first P-type heavily doped regions 111 are arranged along the second direction OY.
[0063] The SCR structure of this embodiment is Figure 1 and Figure 2 Compared with the SCR structure shown in FIG. 1 , by setting the first P-type heavily doped region 111 in the first N-type heavily doped region, that is, the two are in contact with each other, and at the same time dividing the first P-type heavily doped region 111 into a plurality of first P-type heavily doped regions 111 arranged at intervals, the interface between the emitter and the base of the PNP transistor in the SCR structure is realized by Figure 1 and Figure 2 The first P-type heavily doped region 211 as the emitter shown in FIG. 1 is surrounded by the N-type well region 21 as the base region. The contact is changed to Figure 6 The first P-type heavily doped region 111 serving as an emitter is surrounded and contacted by the first N-type heavily doped region 110 serving as a base region. Figure 1 and Figure 2 The current conduction path of the PNP transistor in the SCR structure shown is as follows Figure 1The L1 current path shown needs to pass through the first P-type heavily doped region 211 and the N-type well region 21 with a very low doping concentration to reach the third N-type heavily doped region 222, that is, the base region of the PNP transistor is composed of the N-type well region 21 with a very low doping concentration and the third N-type heavily doped region 222, which are the only way for current conduction. In this embodiment, the current conduction path of the PNP transistor in the SCR structure is as follows: Fig. 9 and Fig.10 The L3 current path shown in the figure directly enters the first N-type heavily doped region 110 with high doping concentration from the first P-type heavily doped region 111 and enters the first N-type heavily doped region 110 through the N-type well region 11. In this current conduction path, the first P-type heavily doped region 111 directly enters the first N-type heavily doped region 110 with high doping concentration, which is the main path of the current conduction path of the PNP transistor. It is well known that the magnitude of the holding voltage of the SCR structure is determined by the current amplification factor β of the PNP transistor and the NPN transistor in the structure. The smaller β is, the greater the holding voltage is. In addition, the current amplification factor β is proportional to the transistor emitter junction injection efficiency γ, and the transistor emitter junction injection efficiency γ is proportional to the N E / N B Proportional relationship, N E is the ion implantation concentration of the transistor emitter, N B is the ion implantation concentration in the base region of the transistor. It can be seen that the ion implantation concentration N E Under the condition of no change, the ion implantation concentration N in the base region of the transistor B The larger the transistor emitter junction injection efficiency γ, the smaller the corresponding transistor current amplification factor β, so the maintenance voltage can be improved. In this embodiment, the ion implantation concentration of the PNP transistor base region in the SCR structure is effectively increased, thereby effectively improving the maintenance voltage of the SCR structure. On the other hand, in this embodiment, the first P-type heavily doped region 111 is set in the first N-type heavily doped region, that is, the two are in contact with each other, and the first P-type heavily doped region 111 is divided into a plurality of first P-type heavily doped regions 111 arranged at intervals, so that the auxiliary trigger current of the NMOS transistor to the SCR structure is Figure 1 The L2 current path, that is, the first N-type heavily doped region 210 passes through the N-type well region 21 to the third N-type heavily doped region 222 and then to the P-type well region 22 is changed to Fig.10 The L4 current path in the circuit, that is, from the first N-type heavily doped region 110 connected as a whole directly to the P-type well region 12, effectively reduces the auxiliary trigger voltage of the NMOS transistor to the SCR structure. Fig.10As shown, due to the addition of the L4 current path, the current path is more likely to reduce the current amplification factor β of the NPN transistor composed of the first P-type heavily doped region 111 and the first N-type heavily doped regions 110 on the left and right sides of the OX direction, thereby further improving the holding voltage of the SCR structure.
[0064] The working process of the SCR structure of this embodiment is mainly as follows: Figure 3 As shown, after voltage is applied to the anode 14 of the SCR device, reverse avalanche breakdown will first occur at the reverse PN junction of the first N-type heavily doped region 110 and the P-type well region 12, and the current will mainly flow from the first N-type heavily doped region 110 connected as a whole into the P-type well region 12. At this time, the two ends of the SCR structure show the breakdown characteristics of a reverse diode; as the breakdown current continues to increase, the potential difference on the resistor of the P-type well region 12 increases until this potential difference causes the forward diode between the P-type well region 12 and the second N-type heavily doped region 120 to turn on. At this time, the two ends of the SCR device show the characteristics of an NPN triode, which is equivalent to the NMOS transistor realizing the auxiliary triggering of the SCR structure; similarly, as the current continues to increase, the forward diodes of the first P-type heavily doped region 111 and the first N-type heavily doped region 110 will also turn on, causing the parasitic PNP triode to turn on, and a positive feedback effect will occur between the NPN structure and the PNP structure, and finally the entire device structure will show the characteristics of an SCR structure.
[0065] As an example, the doping concentration of the first N-type heavily doped region 110 is one order of magnitude greater than the doping concentration of the N-type well region 11. When the doping concentration of the first N-type heavily doped region 110 is one order of magnitude greater than the doping concentration of the N-type well region 11, a significant reduction in the PNP triode emitter junction injection efficiency γ can be achieved. From the perspective of reducing the PNP triode emitter junction injection efficiency γ, the greater the doping concentration of the first N-type heavily doped region 110, the more significant the reduction in the PNP triode emitter junction injection efficiency γ.
[0066] like Figure 5As shown, as an example, along the first direction OX, the length X1 of the first N-type heavily doped region 110 located on the right side of the first P-type heavily doped region 111 is greater than the length X2 of the first P-type heavily doped region, and the length X2 of the first P-type heavily doped region is greater than the length X3 of the first N-type heavily doped region 110 located on the left side of the first P-type heavily doped region 111. Since the first N-type heavily doped region 110 is connected as a whole, its current path can be guaranteed even if the length X3 is very small, and the first P-type heavily doped region 111, as the emitter of the parasitic PNP transistor, can transfer more size to the first N-type heavily doped region 110 located on the right side of the first P-type heavily doped region 111 as the base region on the premise of satisfying the electron emission capability of the emitter, thereby further reducing its emitter junction injection efficiency γ on the premise of ensuring the conduction of the parasitic PNP transistor.
[0067] As a specific example, the doping concentration of the N-type well region 11 is generally selected to be in the order of 1E16, the doping concentration of the P-type well region 12 is generally selected to be in the order of 1E16-1E18, the doping concentration of the first N-type heavily doped region 110 is generally selected to be in the order of 1E20-1E21, the doping concentration of the second N-type heavily doped region 120 is generally selected to be in the order of 1E20-1E21, the doping concentration of the first P-type heavily doped region 111 is generally selected to be in the order of 1E20-1E21, and the doping concentration of the second P-type heavily doped region 121 is generally selected to be in the order of 1E20-1E21. In the process of manufacturing, preferably, the first N-type heavily doped region 110 and the second N-type heavily doped region 120 are completed in the same ion implantation process, and the first P-type heavily doped region 111 and the second P-type heavily doped region 121 are completed in the same ion implantation process.
[0068] like Figure 3 As shown, as an example, the second N-type heavily doped region 120 and the second P-type heavily doped region 121 are separated by an isolation structure, for example, by a shallow trench isolation 16. In addition, the outer sides of the first N-type heavily doped region 110 and the second P-type heavily doped region 121 can also be isolated from other device structures by the shallow trench isolation 16.
[0069] As described above, a plurality of first P-type heavily doped regions 111 are arranged in a spaced relationship in the second direction OY, so there is no excessive restriction on whether the interval 17 between two adjacent first P-type heavily doped regions 111 is the same. Fig.14 As shown, the intervals 17 between the four first P-type heavily doped regions 111 are set to be different. Fig.10 and Fig.11As shown, the interval 17 between two adjacent first P-type heavily doped regions 111 will form a current path for the device anode 14, so preferably, all the first P-type heavily doped regions 111 are set to be the same (that is, the shape and size of all the first P-type heavily doped regions 111 are set to be the same) and are set at equal intervals, which can effectively ensure the uniform flow of the current path. In addition, the arrangement of the first P-type heavily doped regions 111 and the interval 17 at both ends of the first P-type heavily doped regions 111 in the second direction OY is not excessively restricted, for example, Fig.12 As shown in FIG. 1 , the two ends of the second direction OY may be set as the first P-type heavily doped region 111, or may be set as Fig.15 As shown in FIG. 1 , the interval 17 is set at both ends of the second direction OY. Fig.16 and Fig.17 As shown, one end of the two ends of the second direction OY may be set as the interval 17, and the other end may be set as the first P-type heavily doped region 111, which may be set according to actual conditions. Finally, the number of the first P-type heavily doped regions 111 set in the second direction OY is not excessively limited. As long as more than two first P-type heavily doped regions 111 are set at intervals, the SCR structure maintenance voltage can be improved. For example, Fig.12 and Fig.14 Four first P-type heavily doped regions 111 are provided. Fig.13 and Fig.15 Three first P-type heavily doped regions 111 are provided, and of course other numbers of the first P-type heavily doped regions 111 may be provided.
[0070] In this embodiment, the shape of the cross section of the first P-type heavily doped region 111 is not excessively limited, that is, the shape of the first P-type heavily doped region 111 in the horizontal XOY plane can be a regular shape or an irregular shape, for example Fig.11 The rectangular shape in Fig.12 The right-angled trapezoidal shape in Fig.13 From the perspective of process implementation, it is better to set the first P-type heavily doped region 111 to be a rectangle.
[0071] As a preferred example, when the cross section of the first P-type heavily doped region 111 is set to be rectangular, and the intervals 17 between all the first P-type heavily doped regions 111 are set to be the same, as shown in FIG. Fig.11 As shown, the length Y1 of the first P-type heavily doped region 111 along the second direction is 2 to 3 times the distance Y2 between two adjacent first P-type heavily doped regions 111. The smooth flow of the current path can be achieved under the premise of ensuring the uniform flow of the current path. Under this premise, as a specific example, Fig.11As shown, when the length Y3 of the first N-type heavily doped region 110 along the second direction is 36 μm to 44 μm, four first P-type heavily doped regions 111 may be arranged along the second direction in the first P-type heavily doped region 111 .
[0072] like Figure 3 As shown, as an example, part of the first N-type heavily doped region 110 extends to the P-type well region 12 , that is, part of the right side of the first N-type heavily doped region 110 along the OX direction extends to the P-type well region 12 .
[0073] like Figure 3 and Figure 4 As shown, in the doping depth direction, that is, the OZ direction, the doping depth relationship between the first N-type heavily doped region 110 and the first P-type heavily doped region 111 is not strictly limited, and the doping depths of the two can be the same or different, that is, the doping depth of the first N-type heavily doped region 110 and the doping depth of the first P-type heavily doped region 111 can be the same (e.g. Figure 3 As shown), the doping depth of the first N-type heavily doped region 110 may be greater than the doping depth of the first P-type heavily doped region 111, or the doping depth of the first N-type heavily doped region 110 may be less than the doping depth of the first P-type heavily doped region 111 (as shown Figure 4 shown).
[0074] As an example, Figure 7 and Figure 8 As shown, the sizes of the plurality of first P-type heavily doped regions 111 arranged in the second direction OY may be different. For example, one side of at least one of the P-type heavily doped regions 111 may overlap with the side of the first N-type heavily doped region 110 away from the second N-type heavily doped region 120. Figure 7 One side of the first and third of the four first P-type heavily doped regions 111 arranged in the embodiment overlaps with the side of the first N-type heavily doped region 110 away from the second N-type heavily doped region 120, and one side of at least one of the P-type heavily doped regions 111 may be longer than the same side of the other P-type heavily doped regions 111, such as Figure 8 One side of the second and fourth first P-type heavily doped regions 111 among the four first P-type heavily doped regions 111 is longer than the same side of the first and third first P-type heavily doped regions 111. As described above, the interval 17 between two adjacent first P-type heavily doped regions 111 will form a current path for the device anode 14, so there is no excessive restriction on whether the sizes of the plurality of first P-type heavily doped regions 111 are the same, as long as the interval 17 between two adjacent first P-type heavily doped regions 111 is the same, the effect of uniform current can be achieved.
[0075] In summary, the present invention provides an SCR structure, which effectively improves the ion implantation concentration of the base region of the PNP transistor in the SCR structure by disposing a first P-type heavily doped region in a first N-type heavily doped region, that is, the two are in a state of contact with each other, and at the same time divides the first P-type heavily doped region into a plurality of first P-type heavily doped regions disposed at intervals, so that the sides of the plurality of first P-type heavily doped regions are surrounded by the first N-type heavily doped region, thereby effectively improving the holding voltage of the SCR structure; in addition, the auxiliary trigger voltage of the NMOS transistor to the SCR structure can be effectively reduced; finally, the current amplification factor β of the NPN transistor composed of the first P-type heavily doped region and the first N-type heavily doped regions on its left and right sides is reduced, thereby further improving the holding voltage of the SCR structure.
[0076] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.
Claims
1. An SCR structure, characterized in that: The SCR structure comprises: P-type substrate; An N-type well region located on the P-type substrate; A P-type well region located inside the N-type well region; wherein the P-type well region extends from a portion of the upper surface of the N-type well region toward the inside thereof; A first N-type heavily doped region extending from the upper surface of the N-type well region to the interior thereof; a plurality of mutually separated first P-type heavily doped regions located in the first N-type heavily doped region and extending inward from an upper surface of the first N-type heavily doped region; A second N-type heavily doped region and a second P-type heavily doped region separated from each other extending from the upper surface of the P-type well region to the inside thereof; The first N-type heavily doped region and the second N-type heavily doped region are spaced apart, and a gate is formed on the surface of the P-type well region in the space; The first N-type heavily doped region is configured as an anode of the SCR structure, and the gate, the second N-type heavily doped region, and the second P-type heavily doped region are collectively configured as a cathode of the SCR structure.
2. The SCR structure according to claim 1, characterized in that: The first N-type heavily doped region, the second N-type heavily doped region and the second P-type heavily doped region are arranged in sequence along a first direction; a plurality of mutually separated first P-type heavily doped regions are arranged along a second direction; and the first direction is perpendicular to the second direction.
3. The SCR structure according to claim 1, characterized in that: An isolation structure is disposed between the second N-type heavily doped region and the second P-type heavily doped region.
4. The SCR structure according to claim 1, characterized in that: A portion of the first N-type heavily doped region extends to the P-type well region.
5. The SCR structure according to claim 1, characterized in that: The doping depth of the first N-type heavily doped region is the same as the doping depth of the first P-type heavily doped region; or the doping depth of the first N-type heavily doped region is different from the doping depth of the first P-type heavily doped region.
6. The SCR structure according to claim 1, characterized in that: One side of at least one of the P-type heavily doped regions overlaps with a side of the first N-type heavily doped region away from the second N-type heavily doped region.
7. The SCR structure according to claim 1, characterized in that: One side of at least one of the P-type heavily doped regions overlaps with a side of the first N-type heavily doped region close to the second N-type heavily doped region.
8. The SCR structure according to claim 1, characterized in that: All of the first P-type heavily doped regions have the same shape and size and are arranged at equal intervals.
9. The SCR structure according to claim 8, characterized in that: The cross-sectional shape of the first P-type heavily doped region is rectangular.
10. The SCR structure according to claim 9, characterized in that: The length of the first P-type heavily doped regions along their arrangement direction is 2 to 3 times the spacing distance between two adjacent first P-type heavily doped regions.
11. The SCR structure according to claim 1, characterized in that: The doping concentration of the first N-type heavily doped region is at least one order of magnitude greater than the doping concentration of the N-type well region.