TWI382526B - Isolated scr esd device - Google Patents

Description

Isolated 矽controlled rectifier electrostatic protection component

The present invention relates to an isolated controllable rectifier (SCR) Electrostatic Discharge Device (ESD), and more particularly to an electrostatic protection component that can prevent a negative voltage from adversely affecting a circuit.

It is often necessary to use an ESD protection component in an integrated circuit to discharge first when the circuit receives an excessive voltage at the external pin to avoid damaging the internal components of the circuit. One of the electrostatic protection elements is to use a tamper-controlled rectifier. As shown in Fig. 1, an N-type well region 11 and a P-type well region 21 are disposed on the P-type base 100, and a high-concentration P+ is disposed in the N-type well region 11. The doped region 13 and the N+ doped region 15 are provided with a high concentration P+ doped region 23 and an N+ doped region 25 in the P-type well region 21 to form a pseudo-controlled rectifier as illustrated, wherein the P+ doped region 13 is N+ The doped region 15, the N-type well region 11 to the P-type well region 21 constitute a PNP transistor, and the N-type well region 11 constitutes an NPN transistor through the P-type well region 21 to the N+ doped region 25. The external connection pad PAD is electrically connected to the P+ doping region 13 and the N+ doping region 15, and the external ground pad GND is electrically connected to the P+ doping region 23 and the N+ doping region 25, so that when the connection pad PAD receives the high voltage The pilot rectifier can be activated to direct current to the ground pad GND to eliminate.

A disadvantage of the prior art described above is that when the connection pad PAD receives a negative voltage, the junction diodes of the N+ doping region 15, the N-type well region 11 to the P-type substrate 100 will be turned on, resulting from the substrate 100. Current extraction from the connection pad The loss of PAD not only consumes energy, but may cause latch-up of the current, which prevents the internal components of the circuit from working properly. In general, the ESD protection component is not designed to contact the negative voltage of the connection pad PAD, but when the circuit is used to push the power transistor switch in the power supply circuit, it may be oscillated due to the switching of the power transistor switch ( Switching ringing) produces an instantaneous negative voltage.

In view of the above, the present invention is directed to the above-mentioned deficiencies of the prior art, and proposes an isolated step-controlled rectifier electrostatic protection element that can avoid adverse effects of negative voltage on the circuit.

One of the objects of the present invention is to provide an isolated step-by-step rectifier electrostatic protection component.

In order to achieve the above object, in one aspect, the present invention provides an isolated step-by-step rectifier electrostatic protection component comprising: a substrate; a first well region having a first conductivity type in the substrate, the well The region is floating; a first high concentration doped region having a second conductivity type in the first well region; a second well region adjacent to the first well region and having a second conductivity type; a second high concentration doped region having a second conductivity type in the second well region; and a third high concentration doped region having a first conductivity type in the second well region, wherein the first high concentration region The doped region is electrically connected to a connection pad, and the first well region is not provided with a high concentration doped region having a first conductivity type connected to the connection pad.

The above-mentioned isolated 矽-controlled rectifier electrostatic protection component can be in the first well Another high concentration doped region is disposed at the junction of the region and the second well region, and the high concentration doped region may be the first or second conductivity type. Alternatively, another high concentration doped region of the first conductivity type may be disposed at a predetermined distance from the junction of the first well region and the second well region in the first well region, or in the second well region And another high concentration doping region of the second conductivity type is disposed at a predetermined distance from the junction of the first well region and the second well region.

The purpose, technical content, features and effects achieved by the present invention will be more readily understood by the detailed description of the embodiments.

The illustrations of the present specification are schematic and their dimensions are not drawn to scale.

Referring to Figure 2, there is shown a first embodiment of the present invention. As shown in the figure, in the present embodiment, the N-type well region 11 is floating, and only the high-concentration P+ doping region 13 and the N+-doped region 15 are disposed in the N-type well region 11. The connection pad PAD is only connected to the P+ doping region 13. When the connection pad PAD receives a high voltage, its guidance can be eliminated by the illustrated discharge path 200. Different from the prior art, when the connection pad PAD receives a negative voltage, since the P+ doping region 13 and the N-type well region 11 constitute a PN junction, the negative voltage does not affect the circuit, and the negative voltage is No other path can cause the substrate to generate current, thus solving the problems of the prior art.

Figure 3 shows another embodiment of the present invention. In the present embodiment, a high concentration N+ doping region 17 is additionally disposed at the junction of the N-type well region 11 and the P-type well region 21. The N+ doping region 17 is set to adjust the electrostatic protection component Trigger voltage. In detail, the junction formed by the N-type well region 11 and the P-type well region 21 has a higher voltage required for collapse conduction, for example, about 40 V; if the N+ doped region 17 is provided, it can pass N+ The junction of the doped region 17 and the P-type well region 21 effectively reduces the breakdown voltage to, for example, about 12-15 V, so that the voltage-controlled rectifier starts to conduct at a lower voltage, and the electrostatic protection function is activated.

Fig. 4 shows an embodiment similar to Fig. 3, in which a high concentration P+ doping region 27 is provided at the junction of the N-type well region 11 and the P-type well region 21. The purpose of the P+ doping region 27 is also to adjust the trigger voltage of the ESD protection component. The junction formed by the N-type well region 11 and the P+ doped region 27 can also reduce the breakdown voltage to activate the ESD protection function early.

Fig. 5 shows another embodiment of the present invention. In the present embodiment, the N+ doping region 17 is not disposed at the boundary of the N-type well region 11 and the P-type well region 21, but is spaced apart from the P-type well region 21 by a predetermined distance d. According to the length of the distance d, the trigger voltage of the static electricity protection element can be appropriately adjusted to a range between the second figure and the third figure.

Figure 6 shows another embodiment of the present invention. In the present embodiment, the P+ doping region 27 is not disposed at the junction of the N-type well region 11 and the P-type well region 21, but is spaced apart from the P-type well region 21 by a predetermined distance d'. According to the length of the distance d', the trigger voltage of the static electricity protection element can be appropriately adjusted to the range between the second figure and the fourth figure.

The present invention has been described with reference to the preferred embodiments thereof, and the present invention is not intended to limit the scope of the present invention. In the same spirit of the present invention, those skilled in the art can think of various equivalent changes, and should be included in this Within the scope of the invention.

11‧‧‧N type well area

13‧‧‧P+ doped area

15‧‧‧N+ doped area

17‧‧‧N+ doped area

21‧‧‧P type well area

23‧‧‧P+ doped area

25‧‧‧N+ doped area

27‧‧‧P+ doped area

100‧‧‧ base

200‧‧‧discharge path

GND‧‧‧Grounding pad

PAD‧‧‧ connection pad

Figure 1 is a cross-sectional view of a prior art controlled rectifier electrostatic protection element.

2 to 6 show schematic cross-sectional views of several embodiments of the present invention.

11‧‧‧N type well area

13‧‧‧P+ doped area

21‧‧‧P type well area

23‧‧‧P+ doped area

25‧‧‧N+ doped area

200‧‧‧discharge path

GND‧‧‧Grounding pad

PAD‧‧‧ connection pad

Claims (9)

An isolated anti-controlled rectifier electrostatic protection component comprises: a base; a first well region having a first conductivity type in the base body, the well region is floating; and the second well region has a second a first high concentration doped region of a conductive type; a second well region adjacent to the first well region having a second conductivity type; and a second high concentration having a second conductivity pattern in the second well region a doped region; a third high concentration doped region having a first conductivity type in the second well region; and being located in the first well region, the second well region, or the first well region and Another high concentration doping region at the junction of the second well region to adjust a trigger voltage of the static protection component, and the high concentration doping region is not the gate, source or drain of any transistor, wherein the first The high concentration doping region is electrically connected to a connection pad, and the first well region is not provided with a high concentration doping region having a first conductivity type connected to the connection pad. The isostatically controlled rectifier electrostatic protection component of claim 1, wherein the first high concentration doping region, the first well region, the second well region, and the third high concentration doping region are formed. Remote control rectifier. The isostatically controlled rectifier electrostatic protection device of claim 1, wherein the first conductivity type is an N type and the second conductivity type is a P type. The isostatically controlled rectifier electrostatic protection component of claim 1, wherein the another high concentration doping region is a fourth high concentration doping region, the first The four high concentration doped regions are in a first or second conductivity type. The isostatically controlled rectifier electrostatic protection component of claim 1, wherein the another high concentration doping zone is located in the first well zone, at a boundary between the first well zone and the second well zone. a fifth high concentration doped region at a predetermined distance. The isostatically controlled rectifier electrostatic protection component of claim 5, wherein the fifth high concentration doped region is in a first conduction mode. The isostatically controlled rectifier electrostatic protection component of claim 1, wherein the another high concentration doping zone is located in the second well zone, at a boundary between the first well zone and the second well zone. a sixth high concentration doped region at a predetermined distance. The isostatically controlled rectifier electrostatic protection component of claim 7, wherein the sixth high concentration doped region is in a second conduction mode. The isolated step-controlled rectifier electrostatic protection component of claim 1, wherein the second and third high concentration doping regions are electrically connected to a ground pad.