阅读说明：本技术 一种双向硅控整流器及其制备方法 (Bidirectional silicon controlled rectifier and preparation method thereof ) 是由 朱天志 黄冠群 陈昊瑜 邵华 于 2020-03-27 设计创作，主要内容包括：本发明公开了一种双向硅控整流器及其制备方法,实际上是将原先单向无回滞效应硅控整流器阴极的结构全部去除,然后将两个原先单向无回滞效应硅控整流器阳极的结构用P阱左右对称地连接起来,本发明所提出的双向硅控整流器为双向器件,能同时适用于正负高压IO端口的防静电保护电路设计。另外,可通过调节所述第二距离的大小以调整所述双向硅控整流器回滞效应的触发电压,与现有技术中的无回滞效应硅控整流器相比,本发明提出的双向硅控整流器具有较高的触发电压。(The invention discloses a bidirectional silicon controlled rectifier and a preparation method thereof, which practically removes all the original unidirectional silicon controlled rectifier cathode structures without hysteresis effect, and then connects the two original unidirectional silicon controlled rectifier anode structures without hysteresis effect by using P wells in a bilateral symmetry manner. In addition, the triggering voltage of the hysteretic effect of the bidirectional silicon controlled rectifier can be adjusted by adjusting the size of the second distance, and compared with the silicon controlled rectifier without the hysteretic effect in the prior art, the bidirectional silicon controlled rectifier provided by the invention has higher triggering voltage.)

1. A bidirectional scr, comprising:

a semiconductor substrate (10);

a P well (20), a first N well (30) and a second N well (40) which are arranged on the semiconductor substrate (10), wherein the P well (20) is arranged between the first N well (30) and the second N well (40) and is used for connecting the first N well (30) and the second N well (40);

a first P-type heavily doped region (301) and a first N-type lightly doped region (302) are arranged on the first N-well (30) at intervals, a first shallow trench isolation region (303) is arranged on one side, away from the first N-type lightly doped region (302), of the first P-type heavily doped region (301), wherein the first P-type heavily doped region (301) is arranged at a position far away from the P-well (20), the first N-type lightly doped region (302) is arranged at a position close to the P-well (20), the distance between the first P-type heavily doped region (301) and the first N-type lightly doped region (302) is a first distance (D1), and the distance between the first N-type lightly doped region (302) and the P-well (20) is a second distance (D2);

a second P-type heavily doped region (401) and a second N-type lightly doped region (402) are arranged on the second N-well (40) at intervals, a second shallow trench isolation region (403) is arranged on one side, away from the second N-type lightly doped region (402), of the second P-type heavily doped region (401), wherein the second P-type heavily doped region (401) is arranged at a position away from the P-well (20), the second N-type lightly doped region (402) is arranged at a position close to the P-well (20), the distance between the second P-type heavily doped region (401) and the second N-type lightly doped region (402) is equal to the first distance (D1), and the distance between the second N-type lightly doped region (402) and the P-well (20) is equal to the second distance (D2);

the width of the first N-type lightly doped region (302) is a third distance (D3), and the width of the second N-type lightly doped region (402) is the same as the width of the first N-type lightly doped region (302);

the first P-type heavily doped region (301) and the first N-type lightly doped region (302) are connected through a metal phase to form an anode (A) of the bidirectional silicon controlled rectifier, and the second P-type heavily doped region (401) and the second N-type lightly doped region (402) are connected through a metal phase to form a cathode (K) of the bidirectional silicon controlled rectifier.

2. The SCR of claim 1, wherein the trigger voltage of the SCR hysteretic effect is adjusted by adjusting the magnitude of the second distance (D2).

3. The SCR of claim 1 wherein the P-well (20) has a width of a fourth distance (D4), and the SCR is selected by adjusting the first distance (D1), the third distance (D3) and the fourth distance (D4) to determine whether the SCR enters the hysteretic-free mode.

4. The SCR of claim 3, wherein the first distance (D1) is in the range of 0.2um to 10um, the second distance (D2) is in the range of 0um to 2um, the third distance (D3) is in the range of 0.4um to 10um, and the fourth distance (D4) is in the range of 1um to 10 um.

5. A preparation method of a bidirectional silicon controlled rectifier is characterized by comprising the following steps:

providing a semiconductor substrate (10);

a P well (20), a first N well (30) and a second N well (40) are arranged on the semiconductor substrate (10), and the P well (20) is arranged between the first N well (30) and the second N well (40) and used for connecting the first N well (30) and the second N well (40);

arranging a first P-type heavily doped region (301) and a first N-type lightly doped region (302) on the first N well (30) at intervals, wherein a first shallow trench isolation region (303) is arranged on one side, away from the first N-type lightly doped region (302), of the first P-type heavily doped region (301), the first P-type heavily doped region (301) is arranged at a position far away from the P well (20), the first N-type lightly doped region (302) is arranged at a position close to the P well (20), the distance between the first P-type heavily doped region (301) and the first N-type lightly doped region (302) is a first distance (D1), and the distance between the first N-type lightly doped region (302) and the P well (20) is a second distance (D2);

second P-type heavily doped regions (401) and second N-type lightly doped regions (402) are arranged on the second N well (40) at intervals, a second shallow trench isolation region (403) is arranged on one side of the second P-type heavily doped region (401) far away from the second N-type lightly doped region (402), wherein the second heavily P-type doped region (401) is arranged at a position far away from the P well (20), the second N-type lightly doped region (402) is arranged at a position close to the P well (20), the distance between the second P type heavily doped region (401) and the second N type lightly doped region (402) is equal to the first distance (D1), the second N-type lightly doped region (402) is separated from the P-well (20) by the second distance (D2), wherein the width of the first N-type lightly doped region (302) is a third distance (D3), the width of the second N-type lightly doped region (402) is the same as the width of the first N-type lightly doped region (302);

the first P type heavily doped region (301) and the first N type lightly doped region (302) are connected through a metal phase to form an anode (A) of the bidirectional silicon controlled rectifier, and the second P type heavily doped region (401) and the second N type lightly doped region (402) are connected through a metal phase to form a cathode (K) of the bidirectional silicon controlled rectifier.

6. The method of claim 4, further comprising the steps of:

adjusting the trigger voltage of the SCR hysteretic effect by adjusting the size of the second distance (D2).

7. The method of claim 4, further comprising the steps of:

the width of the P-well (20) is a fourth distance (D4);

selecting whether the SCR enters a no-hysteresis mode by adjusting the magnitude of the first distance (D1), the third distance (D3), and the fourth distance (D4).

8. The method as claimed in claim 7, wherein the first distance (D1) is in a range of 0.2um to 10um, the second distance (D2) is in a range of 0um to 2um, the third distance (D3) is in a range of 0.4um to 10um, and the fourth distance (D4) is in a range of 1um to 10 um.

Technical Field

The invention relates to the technical field of semiconductor integrated circuits, in particular to a bidirectional silicon controlled rectifier and a preparation method thereof.

Background

In the field of high-voltage integrated circuit anti-static protection design, the design scheme of the anti-static protection circuit applied to the high-voltage port by multistage series connection of the SCR without hysteresis effect has the advantage of saving layout area and is widely concerned.

Disclosure of Invention

The invention aims to provide a bidirectional silicon controlled rectifier and a preparation method thereof, which are used for solving the problem that the silicon controlled rectifier without hysteresis effect in the prior art cannot be suitable for a negative high-voltage scene.

In order to solve the above technical problem, the present invention provides a bidirectional silicon controlled rectifier, including:

a semiconductor substrate (10);

a P well (20), a first N well (30) and a second N well (40) which are arranged on the semiconductor substrate (10), wherein the P well (20) is arranged between the first N well (30) and the second N well (40) and is used for connecting the first N well (30) and the second N well (40);

a first P-type heavily doped region (301) and a first N-type lightly doped region (302) are arranged on the first N-well (30) at intervals, a first shallow trench isolation region (303) is arranged on one side, away from the first N-type lightly doped region (302), of the first P-type heavily doped region (301), wherein the first P-type heavily doped region (301) is arranged at a position far away from the P-well (20), the first N-type lightly doped region (302) is arranged at a position close to the P-well (20), the distance between the first P-type heavily doped region (301) and the first N-type lightly doped region (302) is a first distance (D1), and the distance between the first N-type lightly doped region (302) and the P-well (20) is a second distance (D2);

a second P-type heavily doped region (401) and a second N-type lightly doped region (402) are arranged on the second N-well (40) at intervals, a second shallow trench isolation region (403) is arranged on one side, away from the second N-type lightly doped region (402), of the second P-type heavily doped region (401), wherein the second P-type heavily doped region (401) is arranged at a position away from the P-well (20), the second N-type lightly doped region (402) is arranged at a position close to the P-well (20), the distance between the second P-type heavily doped region (401) and the second N-type lightly doped region (402) is equal to the first distance (D1), and the distance between the second N-type lightly doped region (402) and the P-well (20) is equal to the second distance (D2);

the width of the first N-type lightly doped region (302) is a third distance (D3), and the width of the second N-type lightly doped region (402) is the same as the width of the first N-type lightly doped region (302);

the first P-type heavily doped region (301) and the first N-type lightly doped region (302) are connected through a metal phase to form an anode (A) of the bidirectional silicon controlled rectifier, and the second P-type heavily doped region (401) and the second N-type lightly doped region (402) are connected through a metal phase to form a cathode (K) of the bidirectional silicon controlled rectifier.

Optionally, the bidirectional silicon controlled rectifier adjusts the trigger voltage of the hysteretic effect of the bidirectional silicon controlled rectifier by adjusting the size of the second distance (D2).

Optionally, the width of the P-well (20) is a fourth distance (D4), and the bidirectional scr selects whether the bidirectional scr enters the no-hysteresis mode by adjusting the sizes of the first distance (D1), the third distance (D3) and the fourth distance (D4).

Optionally, the first distance (D1) has a size range of 0.2um to 10um, the second distance (D2) has a size range of 0um to 2um, the third distance (D3) has a size range of 0.4um to 10um, and the fourth distance (D4) has a size range of 1um to 10 um.

Based on the same inventive concept, the invention also provides a preparation method of the bidirectional silicon controlled rectifier, which comprises the following steps:

providing a semiconductor substrate (10);

a P well (20), a first N well (30) and a second N well (40) are arranged on the semiconductor substrate (10), and the P well (20) is arranged between the first N well (30) and the second N well (40) and used for connecting the first N well (30) and the second N well (40);

arranging a first P-type heavily doped region (301) and a first N-type lightly doped region (302) on the first N well (30) at intervals, wherein a first shallow trench isolation region (303) is arranged on one side, away from the first N-type lightly doped region (302), of the first P-type heavily doped region (301), the first P-type heavily doped region (301) is arranged at a position far away from the P well (20), the first N-type lightly doped region (302) is arranged at a position close to the P well (20), the distance between the first P-type heavily doped region (301) and the first N-type lightly doped region (302) is a first distance (D1), and the distance between the first N-type lightly doped region (302) and the P well (20) is a second distance (D2);

second P-type heavily doped regions (401) and second N-type lightly doped regions (402) are arranged on the second N well (40) at intervals, a second shallow trench isolation region (403) is arranged on one side of the second P-type heavily doped region (401) far away from the second N-type lightly doped region (402), wherein the second heavily P-type doped region (401) is arranged at a position far away from the P well (20), the second N-type lightly doped region (402) is arranged at a position close to the P well (20), the distance between the second P type heavily doped region (401) and the second N type lightly doped region (402) is equal to the first distance (D1), the second N-type lightly doped region (402) is separated from the P-well (20) by the second distance (D2), wherein the width of the first N-type lightly doped region (302) is a third distance (D3), the width of the second N-type lightly doped region (402) is the same as the width of the first N-type lightly doped region (302);

the first P type heavily doped region (301) and the first N type lightly doped region (302) are connected through a metal phase to form an anode (A) of the bidirectional silicon controlled rectifier, and the second P type heavily doped region (401) and the second N type lightly doped region (402) are connected through a metal phase to form a cathode (K) of the bidirectional silicon controlled rectifier.

Optionally, the method further comprises the following steps:

adjusting the trigger voltage of the SCR hysteretic effect by adjusting the size of the second distance (D2).

Optionally, the method further comprises the following steps:

the width of the P-well (20) is a fourth distance (D4);

selecting whether the SCR enters a no-hysteresis mode by adjusting the magnitude of the first distance (D1), the third distance (D3), and the fourth distance (D4).

Optionally, the first distance (D1) has a size range of 0.2um to 10um, the second distance (D2) has a size range of 0um to 2um, the third distance (D3) has a size range of 0.4um to 10um, and the fourth distance (D4) has a size range of 1um to 10 um.

Compared with the prior art, the technical scheme provided by the invention has the following beneficial effects:

the invention provides a bidirectional silicon controlled rectifier and a preparation method thereof, which are characterized in that the cathode structure of the unidirectional silicon controlled rectifier without hysteresis effect in the prior art is completely removed, an N-type heavily doped region of an anode is replaced by an N-type lightly doped region, and then the anode structures of two original unidirectional silicon controlled rectifiers without hysteresis effect are connected by a P well in a bilateral symmetry manner.

In addition, the triggering voltage of the hysteretic effect of the bidirectional silicon controlled rectifier can be adjusted by adjusting the size of the second distance, and compared with the silicon controlled rectifier without the hysteretic effect in the prior art, the bidirectional silicon controlled rectifier provided by the invention has higher triggering voltage.

Drawings

FIG. 1 is a schematic diagram of a SCR structure without hysteresis effect according to the prior art;

FIG. 2 is a schematic diagram of another SCR structure without hysteresis effect proposed in the prior art;

FIG. 3 is a schematic diagram of a bidirectional SCR structure according to an embodiment of the present invention;

FIG. 4 is a schematic flow chart of a method for manufacturing a bidirectional SCR according to another embodiment of the present invention;

fig. 5 is a schematic view of an application scenario for implementing the technical solution of the present invention according to an embodiment of the present invention;

wherein, in fig. 3: 10-semiconductor substrate, 20-P well, 30-first N well, 301-first P type heavily doped region, 302-first N type lightly doped region, 303-first shallow channel isolation region, 40-second N well, 401-second P type heavily doped region, 402-second N type lightly doped region, 403 second shallow channel isolation region, D1-first distance, D2-second distance, D3-third distance, D4-fourth distance, A-anode and K-cathode.

Detailed Description

The following describes in more detail embodiments of the present invention with reference to the schematic drawings. The advantages and features of the present invention will become more apparent from the following description. It is to be noted that the drawings are in a very simplified form and are not to precise scale, which is merely for the purpose of facilitating and distinctly claiming the embodiments of the present invention.

In the description of the present invention, it is to be understood that the terms "center", "upper", "lower", "left", "right", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

Referring to fig. 3, an embodiment of the invention provides a bidirectional scr, including:

a semiconductor substrate 10, a P Well (P-Well)20, a first N Well (N-Well)30 and a second N Well (N-Well)40 which are arranged on the semiconductor substrate 10, the P Well (P-Well)20 is arranged between the first N Well (N-Well)30 and the second N Well (N-Well)40 for connecting the first N Well (N-Well)30 and the second N Well (N-Well)40, a first heavily doped P region (P +)301 and a first lightly doped N region (N L) 302 are arranged on the first N Well (N-Well)30 at intervals, a first heavily doped P63303 isolation region is arranged on one side of the first heavily doped P region (P +)301 which is far away from the first lightly doped N region (N) 302, a second heavily doped P63303 region (N +) which is arranged between the P Well (P-Well)20 and the second N Well (N-Well) 20 at intervals, a P464 + P + S301, a first heavily doped region P + S +.

The width of the first N-type lightly doped region (N L DD)302 is a third distance D3, the width of the second N-type lightly doped region (N L DD)402 is the same as the width of the first N-type lightly doped region (N L DD)302, the first P-type heavily doped region (P +)301 and the first N-type lightly doped region (N L DD)302 are connected by metal to form an anode A of the bidirectional silicon controlled rectifier, and the second P-type heavily doped region (P +)401 and the second N-type lightly doped region (N L DD)402 are connected by metal to form a cathode K of the bidirectional silicon controlled rectifier.

Comparing fig. 2 and fig. 3, it is obvious that the technical solution proposed by the embodiment of the present invention is to actually remove all the structures of the cathode K of the unidirectional hysteretic-free scr in the prior art, and then connect the two structures of the anode a of the original unidirectional hysteretic-free scr with the P-Well (P-Well)20 in a bilateral symmetry manner. As can be seen from the above description and with reference to FIG. 3, the structure of the bidirectional SCR provided by the embodiment of the present invention is symmetrical along the P-Well (P-Well) 20. The bidirectional silicon controlled rectifier provided by the embodiment of the invention is a bidirectional device, and can be simultaneously suitable for the design of an anti-static protection circuit of a positive/negative high-voltage IO port.

Further, the bidirectional scr provided by the embodiments of the invention can adjust the trigger voltage of the hysteretic effect of the bidirectional scr by adjusting the size of the distance between the first N-type lightly doped region (N L DD)302 and the P-Well (P-Well)20 and the distance between the second N-type lightly doped region (N L DD)402 and the P-Well (P-Well)20 (i.e., the second distance D2) within a certain range.

Further, the width of the P-Well (P-Well)20 is a fourth distance D4, and the bidirectional scr selects whether the bidirectional scr enters the no-hysteresis mode by adjusting the distance between the first P-type heavily doped region (P +)301 and the first N-type lightly doped region (N L DD)302 and the distance between the second P-type heavily doped region (P +)401 and the second N-type lightly doped region (N L DD)402 (i.e., the first distance D1), the width of the first N-type lightly doped region (N L DD)302 and the width of the second N-type lightly doped region (N L DD)402 (i.e., the third distance D3) and the fourth distance D4.

It is to be noted that the following range restrictions are proposed for the first distance (D1), the second distance (D2), the third distance (D3), and the fourth distance (D4) in the embodiment of the present invention: the size scope of first distance (D1) is 0.2um ~ 10um, the size scope of second distance (D2) is 0um ~ 2um, the size scope of third distance (D3) is 0.4um ~ 10um, the size scope of fourth distance (D4) is 1um ~ 10 um. It should be understood by those skilled in the art that the sizes of the first distance (D1), the second distance (D2), the third distance (D3) and the fourth distance (D4) are not limited to the ranges provided by the embodiments of the present invention, and other ranges may be selected, but the above ranges provided by the present invention are limited and can be implemented as preferred embodiments of the present invention.

Based on the same inventive concept, another embodiment of the present invention further provides a method for manufacturing a bidirectional scr, please refer to fig. 4, which includes the following steps:

s1: providing a semiconductor substrate 10;

s2: a P-Well (P-Well)20, a first N-Well (N-Well)30, and a second N-Well (N-Well)40 are provided on the semiconductor substrate 10, and the P-Well (P-Well)20 is provided between the first N-Well (N-Well)30 and the second N-Well (N-Well)40 for connecting the first N-Well (N-Well)30 and the second N-Well (N-Well) 40;

s3, arranging a first P type heavily doped region (P +)301 and a first N type lightly doped region (N L DD)302 at intervals on the first N Well (N-Well)30, wherein a first shallow trench isolation region 303 is arranged on one side, away from the first N type lightly doped region (N L DD), of the first P type heavily doped region (P +)301, the first N type lightly doped region (N L DD)302 is arranged at a position close to the P Well (P-Well)20, the distance between the first P type heavily doped region (P +)301 and the first N type lightly doped region (N L DD)302 is a first distance D1, and the distance between the first N type lightly doped region (N L DD)302 and the P (P-Well)20 is a second distance D2;

s4, arranging a second P type heavily doped region (P +)401 and a second N type lightly doped region (N L DD)402 at intervals on the second N Well (N-Well)40, wherein a side, away from the second N type lightly doped region (N L DD)402, of the second P type heavily doped region (P +)401 is provided with a second shallow trench isolation region 403, wherein the second P type heavily doped region (P +)401 is arranged at a position away from the P Well (P-Well)20, the second N type lightly doped region is arranged at a position close to the P Well (P-Well)20, a distance between the second P type heavily doped region (P +)401 and the second N type lightly doped region (P5631 DD)402 is equal to the first distance D1, a distance between the second N type lightly doped region (N L DD)402 and the P Well (P-Well (P5631 DD) 20 is equal to the second distance D2, and the first N type lightly doped region (N L DD)402 is equal to the second N type lightly doped region (N493302 DD)302, wherein the first N type lightly doped region (P +) 302) 3 and the second N type lightly doped region (DD) 302 are spaced at the same distance D2, the same width as the second N4934;

and S5, forming an anode A of the bidirectional silicon controlled rectifier after the first P-type heavily doped region (P +)301 and the first N-type lightly doped region (N L DD)302 are connected by metal, and forming a cathode K of the bidirectional silicon controlled rectifier after the second P-type heavily doped region (P +)401 and the second N-type lightly doped region (N L DD)402 are connected by metal.

Optionally, the method further comprises the following steps:

the trigger voltage of the hysteretic effect of the bidirectional silicon controlled rectifier is adjusted by adjusting the size of the second distance D2.

Optionally, the method further comprises the following steps:

the width of the P-Well (P-Well)20 is a fourth distance D4;

selecting whether the bidirectional SCR enters a no-hysteresis mode by adjusting the magnitude of the first distance D1, the third distance D3, and the fourth distance D4.

Referring to fig. 5, the bidirectional silicon controlled rectifier according to the embodiment of the present invention can be applied to a protection circuit of an input/output terminal of an ESD (Electro-Static discharge) protection circuit and a protection circuit of a power supply to ground, so as to improve the overall ESD protection capability of the chip.

In summary, the bidirectional silicon controlled rectifier and the manufacturing method thereof provided by the present invention actually remove all the structures of the cathode of the original unidirectional non-hysteresis effect silicon controlled rectifier, replace the N-type heavily doped region of the anode with the N-type lightly doped region, and then connect the structures of the anode of the two original unidirectional non-hysteresis effect silicon controlled rectifiers symmetrically left and right by using the P-well.

In addition, the triggering voltage of the hysteretic effect of the bidirectional silicon controlled rectifier can be adjusted by adjusting the size of the second distance, and compared with the silicon controlled rectifier without the hysteretic effect in the prior art, the bidirectional silicon controlled rectifier provided by the invention has higher triggering voltage.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example" or "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. And the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments. Furthermore, various embodiments or examples described in this specification can be combined and combined by those skilled in the art.

The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any way. It will be understood by those skilled in the art that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.