TWM472947U - Dual-directional silicon controlled rectifier - Google Patents

Description

Bidirectionally controlled rectifier

The present invention relates to a Dual-directional Silicon Controlled Rectifier (DSCR), and more particularly to a bidirectionally controlled rectifier having a doped region.

With the advancement of semiconductor technology, the size of metal-oxide-semiconductor field-effect transistors (MOSFETs) has become smaller and smaller, and its size has been reduced to submicron meters or even deep times. Deep submicron meter rating. With this advanced technology, the gate oxide is getting thinner. In this case, it is very likely that damage will occur when a slightly higher voltage is applied. When facing an electrostatic voltage in a general environment, since the voltage value of the electrostatic voltage can be as high as several thousand or even tens of thousands of volts, when designing an integrated circuit, the designer must consider the static electricity before it accumulates to a certain amount. Discharge. Under these conditions, a Silicon Controlled Rectifier (SCR) with low on-resistance, low capacitance, low power consumption, and high power current derivation capability is an effective way to achieve Electromagnetic Interference (EMI). element.

In general, bidirectionally controlled rectifiers have become the mainstream of the I/O protection circuit for positive and negative voltages. The initial controlled rectifiers are directly fabricated on the germanium substrate. Due to their low withstand voltage, the application is limited only to the general integrated circuit process. It is also known that there is a ring-type layout of the controlled rectifier, but its layout area is large, the starting speed is too large due to the structure, and it is not widely Use it in general.

Therefore, in order to improve the startup speed of the controlled rectifier, the designer has reduced the breakdown voltage by modifying the internal MOS structure to modulate the trigger voltage of the rectifier. However, it is worth noting that although this method can quickly start the rectifier rectifier, it also limits the operating voltage of the integrated circuit. That is to say, the operating voltage of the integrated circuit is limited to P+/N well (or N+/P well) in the MOS structure and the breakdown voltage is limited below the breakdown voltage before the occurrence of the punchthrough. When the input voltage is higher than the operating voltage, a malfunction may occur. For example, if the input voltage of the EIA/TIA-232-E specification is 15 volts or so, it is easy to collapse or breakdown early, so it cannot be applied to such applications. On the circuit.

Therefore, how to design a controlled rectifier with good electrostatic protection and at the same time can withstand high working voltage is one of the important research directions in the development of today.

In view of the above problems, the present invention is to provide a bidirectionally controlled rectifier to solve the conventional problems.

The present invention provides a dual-directional silicon controlled rectifier (DSCR), comprising: a substrate, a buried layer, a first well, a second well and a third well, a first semiconductor region, and a second a semiconductor region, a third semiconductor region and a fourth semiconductor region, and a doped region. Wherein, the substrate is in a first conductivity type. The buried layer is on the substrate and is in a second conductivity type. The first well and the second well are located on the buried layer and are all in a first conductivity type. The third well is located on the buried layer and between the first well and the second well, the third well It is a second conductivity type. The first semiconductor region and the second semiconductor region are both located in the first well; the third semiconductor region and the fourth semiconductor region are both located in the second well. A doped region is disposed between the first semiconductor region and the third semiconductor region, the doped region includes a portion of the third well, and the doped region is in a second conductivity type.

According to the bidirectionally controlled rectifier of the present invention, the doped region further includes a portion of the first well and the second well.

According to the bidirectionally controlled rectifier of the present invention, one of the first conductivity type and the second conductivity type is N-type, and the other is P-type.

According to the bidirectionally controlled rectifier of the present invention, when the first semiconductor region and the third semiconductor region are in the first conductivity type, the second semiconductor region and the fourth semiconductor region are in the second conductivity type.

According to the bidirectional voltage controlled rectifier proposed by the present invention, when the first semiconductor region and the third semiconductor region are in the second conductivity type, the second semiconductor region and the fourth semiconductor region are in the first conductivity type.

Therefore, the bidirectionally controlled rectifier according to the present invention is regulated by a doping region between the first semiconductor region and the third semiconductor region, changing the carrier concentration or using a semiconductor having a different carrier concentration in a standard process. The collapse voltage of the junction causes the operating voltage of the integrated circuit to be no longer limited to the conventional breakdown effect or low breakdown point, greatly increasing its application value and industrial utilization.

The above description of the present invention is provided to demonstrate and explain the spirit and principles of the present invention, and to provide a further explanation of the scope of the present patent application. With regard to the features, implementations and effects of the present invention, the preferred embodiment is described in conjunction with the drawings. The details are as follows.

10‧‧‧P type substrate

10a‧‧‧N type substrate

20‧‧‧N type buried layer

20a‧‧‧P type buried layer

31‧‧‧P type first well

31a‧‧‧N type first well

32‧‧‧P type second well

32a‧‧‧N type second well

33‧‧‧N type third well

33a‧‧‧P type third well

34‧‧‧N type fourth well

34a‧‧‧P type fourth well

41‧‧‧N type first semiconductor area

41a‧‧‧P type first semiconductor area

42‧‧‧P type second semiconductor area

42a‧‧‧N type second semiconductor area

43‧‧‧N type third semiconductor area

43a‧‧‧P type third semiconductor area

44‧‧‧P type fourth semiconductor area

44a‧‧‧N type fourth semiconductor area

50‧‧‧N-doped region

50a‧‧‧P type doped area

1000‧‧‧Bidirectional remote control rectifier

1000a‧‧‧Bidirectional remote control rectifier

FIG. 1A is a schematic structural view of a bidirectionally controlled rectifier according to a first embodiment of the present invention.

FIG. 1B is a schematic structural view of a bidirectionally controlled rectifier according to a second embodiment of the present invention.

1C is a schematic structural view of a bidirectionally controlled rectifier according to a third embodiment of the present invention.

1D is a schematic structural view of a bidirectionally controlled rectifier according to a fourth embodiment of the present invention.

Figure 2A is a schematic diagram of the forward operating voltage-current of the bidirectionally controlled rectifier according to "1A".

Figure 2B is a schematic diagram of the negative operating voltage-current of the bidirectionally controlled rectifier according to "1A".

3A is a schematic structural view of a bidirectionally controlled rectifier according to a fifth embodiment of the present invention.

3B is a schematic structural view of a bidirectionally controlled rectifier according to a sixth embodiment of the present invention.

3C is a schematic structural view of a bidirectionally controlled rectifier according to a seventh embodiment of the present invention.

The 3D figure is a schematic structural view of the bidirectionally controlled rectifier according to the eighth embodiment of the present invention.

The detailed features and advantages of the present invention are described in detail in the following detailed description of the embodiments of the present invention. Any related art and related art can easily understand the related purposes and advantages of the present invention.

Fig. 1A is a schematic structural view of a bidirectionally controlled rectifier according to a first embodiment of the present invention. The bidirectionally controlled rectifier 1000 includes a P-type substrate 10 having an N-type thereon N-buried layer (NBL) 20. The N-type buried layer 20 includes a P-type first well 31, a P-type second well 32 and an N-type third well 33, wherein the N-type third well 33 is disposed in the P-type first well 31 and the P-type Between two wells 32.

According to an embodiment of the present invention, an N-type fourth well 34 is further provided between the P-type first well 31, the N-type buried layer 20 and the P-type substrate 10. Similarly, the N-type fourth well 34 may be disposed between the P-type second well 32, the N-type buried layer 20, and the P-type substrate 10. The N-type fourth well 34 may be, but not limited to, an undoped epitaxial layer or any type of conductive type having an N-type, such as an N-type epitaxial layer or an N-type well region.

The P-type first well 31 includes an N-type first semiconductor region 41 and a P-type second semiconductor region 42 which are commonly connected to an anode. The P-type second well 32 includes an N-type third semiconductor region 43 and a P-type fourth semiconductor region 44 that are commonly connected to a cathode. The manner in which the semiconductor region is connected to the anode and the cathode may also be as shown in FIG. 1B, which connects the N-type first semiconductor region 41 and the P-type second semiconductor region 42 to the cathode, and the N-type third. The semiconductor region 43 and the P-type fourth semiconductor region 44 are commonly connected to the anode.

As shown in FIG. 1A, an N-type doped region 50 is disposed between the N-type first semiconductor region 41 and the N-type third semiconductor region 43, and the N-type doped region 50 includes a portion. P-type first well 31, P-type second well 32 and N-type third well 33. Here, the N-type doped region 50 forms a Doped concentration between the N-type first semiconductor region 41, the N-type third semiconductor region 43, the P-type first well 31 and the P-type second well 32. N-type area.

The "1C diagram" is a schematic structural view of a bidirectionally controlled rectifier according to still another embodiment of the present invention. Among them, the N-type doping region 50 can be designed as a discontinuous implant region. Further, "1D" is a two-way controlled rectifier according to another embodiment of the present invention. Schematic diagram of the structure of the device. As shown, wherein the N-type doped region 50 can also selectively include only a portion of the N-type third well 33, and all of the above embodiments can be used to achieve the efficacy of the present invention (described in detail below).

According to an embodiment of the present invention, since the N-type doping region 50 can be used to effectively extend the collapse point between the original N-type first semiconductor region 41 and the P-type first well 31 to the P-type first well 31 and the N-type The junction of the doped regions 50, and likewise the collapse point between the original N-type third semiconductor region 43 and the P-type second well 32 is effectively extended to the junction of the P-type second well 32 and the N-type doped region 50. In this way, the withstand voltage of the bidirectionally controlled rectifier 1000 is thereby effectively changed (i.e., its breakdown voltage is changed). Therefore, the bidirectionally controlled rectifier according to the first to fourth embodiments of the present invention can be used as an effective component for maintaining rectification and electrostatic protection when applied to an I/O voltage higher than an operating voltage.

"2A" and "2B" are schematic diagrams of the forward operating voltage-current and negative operating voltage-current according to the "1A" bidirectionally controlled rectifier, respectively, from "A 2A" and As can be seen in Figure 2B, the breakdown voltage of the bidirectionally controlled rectifier 1000 has been effectively boosted to 20 volts, so even when applied to the EIA/TIA-232-E specification, the input voltage is plus or minus 15 volts. The controlled rectifier 1000 is still applicable without malfunction and can maintain good low signal loss and high electrostatic protection.

The first to fourth embodiments of the present invention (that is, "1A" to "1D") are illustrative of an embodiment in which a P-type substrate is used as a bidirectionally controlled rectifier. The conductivity patterns of the respective components (including the buried layer, the first well to the third well, and the doped region) are all determined according to the conductivity type of the P-type substrate. For example, the bidirectionally controlled rectifier can also be an N-type substrate. As an illustration of another embodiment, "3A" is a bidirectional 矽 according to the fifth embodiment of the present invention. A schematic diagram of the structure of a controlled rectifier using an N-type substrate as its substrate.

The bidirectionally controlled rectifier 1000a includes an N-type substrate 10a, a P-type buried layer 20a, an N-type first well 31a, an N-type second well 32a, a P-type third well 33a, a P-type fourth well 34a, and a P-type doping. The region 50a, wherein the N-type first well 31a includes a P-type first semiconductor region 41a and an N-type second semiconductor region 42a commonly connected to the anode, and the N-type second well 32a includes a P-type third commonly connected to the cathode. The semiconductor region 43a and the N-type fourth semiconductor region 44a. The conductivity patterns of the first semiconductor region, the second semiconductor region, the third semiconductor region and the fourth semiconductor region are not intended to limit the novel range of the novel. In the embodiment proposed by the present invention, when the first semiconductor region and the third semiconductor region are N-type semiconductor type in response to the P-type substrate, the second semiconductor region and the fourth semiconductor region are P-type; When the semiconductor region and the third semiconductor region are of a P-type semiconductor type in response to the N-type substrate, the second semiconductor region and the fourth semiconductor region are N-type, and the conductive type can be designed according to actual circuit application conditions.

Secondly, with the first embodiment of the present invention, the connection mode of the bidirectionally controlled rectifier 1000a to the anode and the cathode can also be interchanged, and the P-type doping region 50a can also be selectively set as a discontinuous implant region. Or only part of the P-type third well 33a, as shown in "3B", "3C" and "3D", respectively, can also be used to achieve the effects of the present invention.

Therefore, in summary, the purpose of the present invention is to provide a bidirectionally controlled rectifier to effectively prevent damage to the semiconductor component caused by static electricity and to maintain its high electrostatic protection capability.

Another object of the present invention is to provide a bidirectionally controlled rectifier having a doped region for effectively modulating the concentration of a carrier in a doped region or using a semiconductor having a different carrier concentration in a standard process. The breakdown voltage of the integrated circuit, at the I/O voltage far When the voltage is higher than the working voltage, there will be no problem of malfunction, which effectively solves the problem that the trigger voltage of the conventional controlled rectifier is limited.

Although the present invention has been described above with reference to the preferred embodiments thereof, it is not intended to limit the present invention. Any one skilled in the art can make some changes and refinements without departing from the spirit and scope of the present invention. The scope of patent protection shall be subject to the definition of the scope of the patent application attached to this specification.

10‧‧‧P type substrate

20‧‧‧N type buried layer

31‧‧‧P type first well

32‧‧‧P type second well

33‧‧‧N type third well

34‧‧‧N type fourth well

41‧‧‧N type first semiconductor area

42‧‧‧P type second semiconductor area

43‧‧‧N type third semiconductor area

44‧‧‧P type fourth semiconductor area

50‧‧‧N-doped region

1000‧‧‧Bidirectional remote control rectifier

Claims (10)

A dual-directional Silicon Controlled Rectifier (DSCR) includes: a substrate in a first conductivity type; a buried layer on the substrate and a second conductivity type; a first well and a second well are located on the buried layer and are all in the first conductivity type; a third well is located on the buried layer, and in the first well and the second well The third well is in the second conductivity type; a first semiconductor region and a second semiconductor region are located in the first well; a third semiconductor region and a fourth semiconductor region are located in the first semiconductor region a second well; and a doped region between the first semiconductor region and the third semiconductor region, the doped region comprising a portion of the third well, and the doped region is The second conductivity type. The bidirectionally controlled rectifier of claim 1, wherein the doped region further comprises a portion of the first well and the second well. The bidirectionally controlled rectifier of claim 1, wherein the first conductivity type is one of an N type or a P type, and the second conductivity type is another one of an N type or a P type. The bidirectionally controlled rectifier of claim 1, wherein the first semiconductor region and the second semiconductor region are connected to an anode, and the third semiconductor region and the fourth semiconductor region are connected to a cathode. The bidirectionally controlled rectifier of claim 1, wherein the first semiconductor region and the second semiconductor are The body region is connected to a cathode, and the third semiconductor region and the fourth semiconductor region are connected to an anode. The bidirectionally controlled rectifier according to claim 1, further comprising at least one fourth well connected between the first well, the buried layer and the substrate, wherein the fourth well is in the second conductivity type. The bidirectionally controlled rectifier of claim 6, wherein the fourth well is an epitaxy layer. The bidirectionally controlled rectifier according to claim 1, further comprising at least one fourth well connected between the second well, the buried layer and the substrate, wherein the fourth well is in the second conductivity type. The bidirectionally controlled rectifier of claim 8, wherein the fourth well is an epitaxy. The bidirectionally controlled rectifier of claim 1, wherein the first semiconductor region and the third semiconductor region are one of the first conductivity type or the second conductivity type, the second semiconductor region and the The fourth semiconductor region is the other of the first conductivity type or the second conductivity type.