Scr device and chip

Abstract

The application provides a silicon controlled rectifier (SCR) device, which comprises a high-voltage P well region and a high-voltage N well region. The high-voltage P well region is sequentially provided with a first P+ doped region and a first N+ doped region. The high-voltage N well region is sequentially provided with a second P+ doped region and a second N+ doped region, and a preset normal-pressure P well region is arranged below the first N+ doped region and / or a preset normal-pressure N well region is arranged below the second P+ doped region. In the SCR device and chip, the preset normal-pressure P well region is formed below the first N+ doped region in the high-voltage P well region and / or the preset normal-pressure N well region is formed below the second P+ doped region in the high-voltage N well region, the recombination efficiency of the emitter injection carriers of the SCR device is improved, the regenerative feedback effect of the SCR device in the conduction process is inhibited, the holding current is improved, and the latch-up phenomenon of the SCR device under the electrostatic protection impact is avoided.

Description

Technical Field

[0001] This application relates to the field of electrostatic discharge protection technology for integrated circuits, and more specifically, to a silicon controlled rectifier (SCR) device and chip. Background Technology

[0002] Electrostatic discharge (ESD) protection plays a crucial role in chip-level reliability design. By designing dedicated ESD protection units and placing them in the overall chip protection network, reliable and effective protection can be provided for the functional circuits inside integrated circuits under transient, low-charge, and high-voltage electrostatic shocks.

[0003] For ESD protection design of high-voltage integrated circuits, on-chip protection based on SCRs is widely used as an ESD protection structure due to its advantages such as the strongest discharge capability per unit area, low parasitic capacitance, and simple structure. However, traditional SCR devices have a deep hysteresis curve, and latch-up must be avoided during use. Summary of the Invention

[0004] This application provides an SCR device and chip, which at least solves the problem of latch-up occurring during the use of the SCR device.

[0005] The SCR device according to this application includes a high-voltage P-well region and a high-voltage N-well region. The high-voltage P-well region is sequentially provided with a first P+ doped region and a first N+ doped region. The high-voltage N-well region is sequentially provided with a second P+ doped region and a second N+ doped region. A preset atmospheric pressure P-well region is disposed below the first N+ doped region and / or a preset atmospheric pressure N-well region is disposed below the second P+ doped region.

[0006] The chip in this application includes the SCR device of any of the above embodiments.

[0007] In the SCR device and chip of this application, a preset constant-pressure P-well region is formed below the first N+ doped region in the high-pressure P-well region and / or a preset constant-pressure N-well region is formed below the second P+ doped region in the high-pressure N-well region. This improves the recombination efficiency of carriers injected into the emitter of the SCR device, suppresses the regenerative feedback effect of the SCR device during the conduction process, increases the holding current, and avoids latch-up phenomenon of the SCR device under ESD impact.

[0008] Additional aspects and advantages of embodiments of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of embodiments of this application. Attached Figure Description

[0009] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, wherein: Figure 1 This is a schematic diagram of the structure of an SCR device with a preset atmospheric pressure P-well region and a preset atmospheric pressure N-well region nested in certain embodiments of this application; Figure 2 This is a schematic diagram of the structure of an SCR device with a preset atmospheric pressure P-well region nested in certain embodiments of this application; Figure 3 This is a schematic diagram of the structure of an SCR device with a preset atmospheric pressure N-well region nested in certain embodiments of this application; Figure 4 This is a schematic diagram of an SCR device without a pre-set atmospheric pressure P-well region and a pre-set atmospheric pressure N-well region. Figure 5 yes Figure 4 The SRH carrier recombination diagram of the SCR device is shown below; Figure 6 yes Figure 3 The SRH carrier recombination diagram of the SCR device is shown below; Figure 7 yes Figure 2 The SRH carrier recombination diagram of the SCR device is shown below; Figure 8 yes Figure 1 The SRH carrier recombination diagram of the SCR device is shown below; Figure 9 yes Figure 1 , Figure 2 , Figure 3 and Figure 4 The simulation data diagram of the SCR device is shown below; Figure 10 This is a schematic diagram of a chip according to certain embodiments of this application. Detailed Implementation

[0010] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the embodiments of this application, and should not be construed as limiting the embodiments of this application.

[0011] Please see Figure 1This application provides an SCR device 100. The SCR device 100 includes a high-voltage P-well region 10 and a high-voltage N-well region 30. The high-voltage P-well region 10 is sequentially provided with a first P+ doped region 11 and a first N+ doped region 13. The high-voltage N-well region 30 is sequentially provided with a second P+ doped region 31 and a second N+ doped region 33. A preset atmospheric pressure P-well region 20 is provided below the first N+ doped region 13 and / or a preset atmospheric pressure N-well region 40 is provided below the second P+ doped region 31.

[0012] In the SCR device 100 of this application, a preset constant-pressure P-well region 20 is formed below the first N+ doped region 11 in the high-pressure P-well region 10 and / or a preset constant-pressure N-well region 40 is formed below the second P+ doped region 31 in the high-pressure N-well region 30. This improves the recombination efficiency of carriers injected into the emitter of the SCR device 100, suppresses the regenerative feedback effect of the SCR device 100 during the conduction process, increases the holding current, and avoids latch-up phenomenon in the SCR device 100.

[0013] Specifically, in the SCR device 100, the high-voltage P-well region 10 can be disposed on the left side of the SCR device 100, and the high-voltage N-well region 30 can be disposed on the right side of the SCR device 100. The first P+ doped region 11 and the first N+ doped region 13 form the cathode, and the second P+ doped region 31 and the second N+ doped region 33 form the anode.

[0014] A preset atmospheric pressure P-well region 20 is disposed below the first N+ doped region 13 and / or a preset atmospheric pressure N-well region 40 is disposed below the second P+ doped region 31, including: Figure 1 As shown, a preset atmospheric pressure P-well region 20 is disposed below the first N+ doped region 13, and a preset atmospheric pressure N-well region 40 is disposed below the second P+ doped region 31. Alternatively, as... Figure 2 As shown, a preset atmospheric pressure P-well region 20 is disposed below the first N+ doped region 13. Alternatively, as... Figure 3 As shown, a preset atmospheric pressure N-well region 40 is provided below the second P+ doped region 31.

[0015] Specifically, the preset constant voltage P-well region 20 is a constant voltage 5V P-well region, and the preset constant voltage N-well region 40 is a constant voltage 5V N-well region. This increases the carrier recombination rate of the SCR device 100 and ensures that even after the transmission line pulse (TLP) voltage of the SCR device 100 hysteresis below the power supply voltage, latch-up of the internal circuit of the SCR device 100 can still be avoided. This allows the SCR device 100 to meet the design requirements of a high-voltage ESD protection device, which has significant advantages.

[0016] In this application, by setting the number and type of the constant pressure wells (preset constant pressure P-well region 20 and preset constant pressure N-well region 40) in the SCR device 100, the overall holding current of the SCR device 100 is adjusted to meet the design requirements for ESD latch-up resistance.

[0017] Please see Figure 1 The SCR device 100 also includes a P-type substrate 50. A high-voltage P-well region 10 and a high-voltage N-well region 30 are disposed on the P-type substrate 50. The high-voltage P-well region 10 is disposed on the left side of the P-type substrate 50, and the high-voltage N-well region 30 is disposed on the right side of the P-type substrate 50.

[0018] In some embodiments, the high-voltage P-well region 10 and the high-voltage N-well region 30 are connected. That is, the high-voltage P-well region 10 and the high-voltage N-well region 30 are tangent.

[0019] In some embodiments, the first P+ doped region 11 and the first N+ doped region 13 are spaced apart in the high-voltage P-well region 10. The second P+ doped region 31 and the second N+ doped region 33 are spaced apart in the high-voltage N-well region 30. Specifically, the spacing between the first P+ doped region 11 and the first N+ doped region 13 may be the same as the spacing between the second P+ doped region 31 and the second N+ doped region 33; or, the spacing between the first P+ doped region 11 and the first N+ doped region 13 may be different from the spacing between the second P+ doped region 31 and the second N+ doped region 33.

[0020] In this application, the first N+ doped region 13 in the high-voltage P-well region 10 and the second P+ doped region 31 in the high-voltage N-well region 30 are spaced apart, and the spacing between them is the same as the spacing between the first P+ doped region 11 and the first N+ doped region 13; or, the spacing between them is the same as the spacing between the second P+ doped region 31 and the second N+ doped region 33.

[0021] Specifically, the first P+ doped region 11, the first N+ doped region 13, the second P+ doped region 31, and the second N+ doped region 33 are all source regions.

[0022] Please see Figure 1 In some embodiments, the first P+ doped region 11 is provided with a first metal region 111, and the first N+ doped region 13 is provided with a second metal region 131. The first metal region 111 can be connected to the second metal region 131, and both the first metal region 111 and the second metal region 131 are grounded.

[0023] In some embodiments, the second P+ doped region 31 is provided with a third metal region 311, and the second N+ doped region 33 is provided with a fourth metal region 331. Both the third metal region 311 and the fourth metal region 331 are connected to the electrostatic input terminal.

[0024] Typically, in SCR devices that do not have a preset atmospheric pressure P-well region 20 and / or a preset atmospheric pressure N-well region 40 (such as... Figure 4 As shown in the figure, at the electrostatic input terminal V ESD The working principle during an ESD impact is as follows: at V ESD When a forward bias is applied, the PN junction formed by the high-voltage N-well and high-voltage P-well regions is reverse biased when the voltage is low, resulting in only a small leakage current. Under ESD impact, the anode voltage gradually increases, causing avalanche breakdown and generating a large number of electron-hole pairs. Holes flow into the high-voltage P-well region and out through the first P+ doped region of the cathode. The resulting hole current flows through the resistor Rpwell of the high-voltage P-well region, forming a voltage drop. When the voltage drop reaches above 0.7V, the lateral NPN transistor turns on. Simultaneously, a large number of electrons enter the second N+ doped region of the anode through the high-voltage N-well region. The resulting electron current flows through the resistor Rnwell of the high-voltage N-well region, forming a voltage drop that turns on the PNP transistor. Subsequently, the PNP and NPN transistors are structurally back-to-back, forming a positive feedback system. Under the influence of electrical modulation, the SCR device exhibits a significant hysteresis in its IV characteristic curve when encountering ESD impact. When the current in an SCR device cyclically amplifies, the sustaining voltage (TLP) of the SCR device hysteresis to a very small value, forming a low-impedance discharge path (PNPN), discharging a large amount of ESD current until the SCR device burns out due to thermal breakdown caused by heat accumulation. Because the sustaining voltage of an SCR device is lower than the normal supply voltage of high-voltage integrated circuits, latch-up is very likely to occur during the application of SCR devices, burning out the internal circuitry.

[0025] Please see Figure 1 In one embodiment, a 5V N-well region (preset atmospheric pressure N-well region 40) is nested directly below the second P+ doped region 31 of the anode in the high-voltage N-well region 30, locally increasing the concentration of the high-voltage N-well region 30. The nesting of the 5V N-well region ensures that during the triggering process of the SCR device 100, a portion of the non-equilibrium holes emitted from the second P+ doped region 31 of the anode will recombine, requiring a larger current to sustain the SCR device 100, thus achieving a high sustaining current for the SCR device 100. Furthermore, a 5V P-well region (preset atmospheric pressure P-well region 20) is nested directly below the first N+ doped region 13 of the cathode in the high-voltage P-well region 10, increasing the non-equilibrium electrons emitted from the emitter of the first N+ doped region 13 of the cathode, thereby increasing the sustaining current (i.e., TLP current, relative to V) of the SCR device 100. ESD The corresponding current is increased to avoid latch-up in the internal circuitry of the SCR device 100.

[0026] Please see Figure 2In another embodiment, a P-well region with a normal voltage of 5V (preset normal voltage P-well region 20) is nested directly below the first N+ doped region 13 of the cathode in the high voltage P-well region 10. This increases the non-equilibrium electrons emitted by the emitter of the first N+ doped region 13 of the cathode, thereby increasing the sustaining current of the SCR device 100 and simplifying the structure of the SCR device 100, effectively reducing the manufacturing cost of the SCR device 100.

[0027] Please see Figure 3 In another embodiment, a 5V N-well region (preset atmospheric pressure N-well region 40) is nested directly below the second P+ doped region 31 of the anode in the high-voltage N-well region 30, locally increasing the concentration of the high-voltage N-well region 30. The nesting of the 5V N-well region allows some of the non-equilibrium holes emitted from the second P+ doped region 31 of the anode to recombine during the triggering process of the SCR device 100. This results in a higher current being required to sustain the SCR device 100, increasing its sustaining current. This also simplifies the structure of the SCR device 100 and effectively reduces its manufacturing cost.

[0028] Specifically, the working principle of the SCR device 100 nested with a preset atmospheric pressure P-well region 20 and / or a preset atmospheric pressure N-well region 40 was simulated and analyzed using Sentaurus TCAD software, and the change of the sustaining current of the SCR device 100 was analyzed in combination with the obtained SRH carrier recombination diagram.

[0029] Figure 5 The SRH carrier recombination diagram is shown for an SCR device that does not have a pre-set atmospheric pressure P-well region 20 and / or a pre-set atmospheric pressure N-well region 40 nested within it. Figure 6 The SRH carrier recombination diagram of the SCR device 100 after nesting the preset atmospheric pressure N-well region 40 (atmospheric pressure 5V N-well region) is shown in combination with... Figure 5 and Figure 6 Comparative analysis shows that the carrier recombination rate in the SCR device 100 with the preset atmospheric pressure N-well region 40 is higher than that in the SCR device without the preset atmospheric pressure P-well region 20 and / or the preset atmospheric pressure N-well region 40. This allows the SCR device 100 with the preset atmospheric pressure N-well region 40 to effectively suppress the regenerative feedback during the conduction process of the SCR device 100, and requires a larger sustaining voltage to ensure the conduction of the SCR device 100, thus achieving a high sustaining current for the SCR device 100.

[0030] Figure 7 The SRH (SRH stands for indirect recombination) carrier recombination diagram of the SCR device 100 after nesting the preset atmospheric pressure P-well region 20 (atmospheric pressure 5V P-well region) is combined with Figure 5 and Figure 7Comparative analysis shows that the carrier recombination rate in the SCR device 100 with the preset atmospheric pressure P-well region 20 is higher than that in the SCR device without the preset atmospheric pressure P-well region 20 and / or the preset atmospheric pressure N-well region 40. This allows the SCR device 100 with the preset atmospheric pressure P-well region 20 to effectively suppress the regenerative feedback during the conduction process of the SCR device 100, and requires a larger sustaining voltage to ensure the conduction of the SCR device 100, thus achieving a high sustaining current for the SCR device 100.

[0031] Figure 8 The SRH carrier recombination diagram of the SCR device 100 after nesting the preset atmospheric pressure P-well region 20 (5V atmospheric pressure P-well region) and the preset atmospheric pressure N-well region 40 (5V atmospheric pressure N-well region) is shown. The carrier recombination rate of the SCR device 100 after nesting the preset atmospheric pressure P-well region 20 (5V atmospheric pressure P-well region) and the preset atmospheric pressure N-well region 40 (5V atmospheric pressure N-well region) is higher than that of the other three types of SCR devices, and much higher than that of the SCR device without the preset atmospheric pressure P-well region 20 and / or the preset atmospheric pressure N-well region 40. This can suppress the regenerative feedback effect during the conduction process of the SCR device 100, so that the SCR device 100 needs a larger holding current to ensure the conduction of the SCR device 100.

[0032] Please see Figure 9 The Sentaurus TCAD software was used to simulate and analyze the four types of SCR devices mentioned above, obtaining TLP simulation data graphs. The ESD performance of each SCR device was then analyzed based on these TLP simulation data graphs. In each simulation data graph, the horizontal axis represents the TLP voltage, i.e., V. ESD The unit is V; the vertical axis represents the TLP current, which is related to V. ESD The corresponding current, in amperes (A).

[0033] Specifically, the IV characteristic curve of the SCR device without the preset atmospheric pressure P-well region 20 and / or the preset atmospheric pressure N-well region 40 is denoted as ref and represented by a square line; the IV characteristic curve of the SCR device 100 with the preset atmospheric pressure N-well region 40 (atmospheric pressure 5V N-well region) is denoted as SH_N and represented by a circular line; the IV characteristic curve of the SCR device 100 with the preset atmospheric pressure P-well region 20 (atmospheric pressure 5V P-well region) is denoted as SH_P and represented by an equilateral triangle line; the IV characteristic curve of the SCR device 100 with both the preset atmospheric pressure P-well region 20 (atmospheric pressure 5V P-well region) and the preset atmospheric pressure N-well region 40 (atmospheric pressure 5V N-well region) is denoted as SH_N SH_P and represented by an inverted triangle line. Simulation data from various SCR devices show that when the three types of SCR devices 100 in this embodiment are nested within preset atmospheric pressure wells (preset atmospheric pressure P-well region 20 and / or preset atmospheric pressure N-well region 40), the preset atmospheric pressure wells are only positioned directly below the doped regions (first N+ doped region 13 and / or second P+ doped region 31), ensuring that the voltage of the device (formed by high-voltage P-well region 10 and high-voltage N-well region 30) remains around 23V. Figure 9 The first inflection point of the four curves (ref, SH_N, SH_P, SH_N, SH_P) is around 23V, indicating that the doping concentration on both sides determining the breakdown of the device has not changed. When the TLP voltage of the SCR device changes from 2.5V to 6V again, the TLP current corresponding to the ref curve is less than 0.5A, while the TLP currents corresponding to the SH_N and SH_P curves are between 0.5A and 0.9A respectively, and the TLP current corresponding to the SH_N and SH_P curves is 1.3A. The SCR device 100, which nests the preset constant voltage P-well region 20 (constant voltage 5V P-well region) and the preset constant voltage N-well region 40 (constant voltage 5V N-well region), obtains a higher sustaining current, and the effect of avoiding latch-up phenomenon in the internal circuit of the SCR device 100 is better.

[0034] In summary, in the SCR device 100 of this application, a preset constant-voltage P-well region 20 is formed below the first N+ doped region 11 in the high-voltage P-well region 10 and / or a preset constant-voltage N-well region 40 is formed below the second P+ doped region 31 in the high-voltage N-well region 30. This improves the recombination efficiency of carriers injected into the emitter of the SCR device 100, suppresses the regenerative feedback effect of the SCR device 100 during the conduction process, increases the holding current, and even if the TLP voltage of the SCR device 100 hysteresis below the power supply voltage, it can still avoid latch-up of the SCR device 100. This gives the SCR device 100 a significant advantage in the design of high-voltage ESD protection devices.

[0035] Please see Figure 10This application also provides a chip 1000. The chip 1000 includes the SCR device 100 of any of the above embodiments. In the chip 1000 of this application, by providing an SCR device 100 with a high holding current in the chip 1000, the internal circuitry of the chip 1000 can be better protected.

[0036] In the description of this specification, the references to terms such as "some embodiments," "in one example," "exemplarily," etc., indicate that a specific feature, structure, material, or characteristic described in connection with the described embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0037] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more executable instructions for implementing a particular logical function or process, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the function involved, as will be understood by those skilled in the art to which embodiments of this application pertain.

[0038] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A silicon controlled rectifier (SCR) device, characterized in that, include: A high-voltage P-well region, wherein a first P+ doped region and a first N+ doped region are sequentially disposed therein; and A high-pressure N-well region is provided, wherein a second P+ doped region and a second N+ doped region are sequentially disposed in the high-pressure N-well region, and a preset atmospheric pressure P-well region is disposed below the first N+ doped region; or, a preset atmospheric pressure P-well region is disposed below the first N+ doped region, and a preset atmospheric pressure N-well region is disposed below the second P+ doped region, wherein the thickness of the preset atmospheric pressure P-well region is greater than the thickness of the first N+ doped region, and the thickness of the preset atmospheric pressure N-well region is greater than the thickness of the second P+ doped region.

2. The SCR device according to claim 1, characterized in that, The preset atmospheric pressure P-well region is an atmospheric pressure 5V P-well region, and the preset atmospheric pressure N-well region is an atmospheric pressure 5V N-well region.

3. The SCR device according to claim 1, characterized in that, The SCR device also includes a P-type substrate, on which the high-voltage P-well region and the high-voltage N-well region are sequentially disposed.

4. The SCR device according to claim 3, characterized in that, The high-pressure P-well region and the high-pressure N-well region are connected.

5. The SCR device according to claim 1, characterized in that, The first P+ doped region, the first N+ doped region, the second P+ doped region, and the second N+ doped region are all source regions.

6. The SCR device according to claim 1, characterized in that, The first P+ doped region and the first N+ doped region are disposed alternately in the high-voltage P-well region, and the second P+ doped region and the second N+ doped region are disposed alternately in the high-voltage N-well region.

7. The SCR device according to claim 1, characterized in that, The first P+ doped region is provided with a first metal region, and the first N+ doped region is provided with a second metal region. Both the first metal region and the second metal region are grounded.

8. The SCR device according to claim 1, characterized in that, The second P+ doped region is provided with a third metal region, and the second N+ doped region is provided with a fourth metal region. Both the third metal region and the fourth metal region are connected to the electrostatic input terminal.

9. A chip, characterized in that, Includes the SCR device according to any one of claims 1 to 8.

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