CN-122028506-A - Low-voltage SCR device

Abstract

The application provides a low-voltage SCR device which comprises a substrate, a first well region, a second well region, at least one first PN junction unit, at least one second PN junction unit, a plurality of shallow trench isolation structures, a third PN junction unit and a first heavily doped region, wherein the third PN junction unit and the first heavily doped region are respectively positioned in the first well region and the second well region and between the first PN junction unit and the second PN junction unit. According to the application, the third PN junction unit is introduced into the first well region or the second well region, so that the third PN junction unit and the first well region or the second well region form a PN junction, and the breakdown voltage of the PN junction can be adjusted along with the change of the distance between the third PN junction units, so that the trigger voltage of the device can be dynamically reduced according to the requirement.

Inventors

• FAN WEISHENG

Assignees

• 华虹半导体(无锡)有限公司

Dates

Publication Date

20260512

Application Date

20260129

Claims (8)

1. 1. A low voltage SCR device, comprising: A substrate; a first well region of a first conductivity type, the first well region being located in the substrate; a second well region of a second conductivity type, the second well region being located in the substrate and adjacent to the first well region; at least one first PN junction unit located in the first well region; At least one second PN junction unit located in the second well region; A third PN junction unit and a first heavily doped region, wherein the third PN junction unit and the first heavily doped region are respectively located in the first well region and the second well region, and the third PN junction unit and the first heavily doped region are located between the first PN junction unit and the second PN junction unit; the shallow trench isolation structures are positioned among different well regions, among different PN junction units and among the PN junction units; the first PN junction unit is connected with a high level, the second PN junction unit is connected with a low level, and the third PN junction unit is electrically connected with a heavily doped region with the same conductivity type in the first heavily doped region.
2. 2. The low voltage SCR device of claim 1, wherein the first PN junction unit comprises an N-type doped second heavily doped region and a P-type doped third heavily doped region positioned on the right side of the second heavily doped region, and the shallow trench isolation structure is arranged between the second heavily doped region and the third heavily doped region.
3. 3. The low voltage SCR device of claim 2, wherein the second PN junction unit comprises a fourth heavily doped region with N type doping and a fifth heavily doped region with P type doping positioned on the right side of the fourth heavily doped region, and the shallow trench isolation structure is arranged between the fourth heavily doped region and the fifth heavily doped region.
4. 4. The low voltage SCR device of claim 3, wherein the third PN junction unit includes a sixth heavily doped region doped with N-type and a seventh heavily doped region doped with P-type located on the right side of the sixth heavily doped region and spaced apart from the sixth heavily doped region.
5. 5. The low voltage SCR device of claim 4, wherein in the third PN junction cell, the sixth heavily doped region and the seventh heavily doped region are located in the same active region.
6. 6. The low voltage SCR device of claim 5, wherein the first heavily doped region is a P-type heavily doped region or an N-type heavily doped region.
7. 7. The low voltage SCR device of claim 6, wherein when the first heavily doped region is a P-type heavily doped region, the third PN junction cell is located in the first well region, the first heavily doped region is located in the second well region, and the seventh heavily doped region in the third PN junction cell is electrically connected to the first heavily doped region.
8. 8. The low voltage SCR device of claim 6, wherein when the first heavily doped region is an N-type heavily doped region, the first heavily doped region is located in the first well region, the third PN junction unit is located in the second well region, and the sixth heavily doped region in the third PN junction unit is electrically connected to the first heavily doped region.

Description

Low-voltage SCR device Technical Field The application relates to the technical field of integrated circuit manufacturing, in particular to a low-voltage SCR device. Background As the process node advances, the gate oxide thickness is further reduced, resulting in the situation that the breakdown voltage of the gate oxide is smaller than that of the PN junction, and the window reserved for ESD (Electro-STATIC DISCHARGE, electrostatic discharge) design is narrower and narrower, and meanwhile, the integration level is improved, so that the area of the ESD device is further compressed. The ESD capability per unit area of an SCR (Silicon Controlled Rectifier) device is much greater than that of a conventional structure device, but the breakdown voltage (trigger voltage) of the SCR is difficult to be further lowered. Referring to fig. 1, fig. 1 is a schematic structure diagram of a first SCR device in the prior art, an N type heavily doped region (n+) 5 is introduced between an N type well region 2 and a P type well region 3 to form an n+/PW PN junction so as to reduce the SCR trigger voltage, or referring to fig. 2, fig. 2 is a schematic structure diagram of a second SCR device in the prior art, and a gate structure 6 is formed on the P type well region 3 to form an NMOS device, so that the second SCR device is capable of reducing the trigger voltage by introducing the NMOS device. However, the trigger voltage of the two SCR device structures is still higher, and the sustain voltage is lower. Disclosure of Invention The application provides a low-voltage SCR device, which can solve the problems of higher trigger voltage and lower maintenance voltage of the traditional SCR device. The embodiment of the application provides a low-voltage SCR device, which comprises: A substrate; a first well region of a first conductivity type, the first well region being located in the substrate; a second well region of a second conductivity type, the second well region being located in the substrate and adjacent to the first well region; at least one first PN junction unit located in the first well region; At least one second PN junction unit located in the second well region; A third PN junction unit and a first heavily doped region, wherein the third PN junction unit and the first heavily doped region are respectively located in the first well region and the second well region, and the third PN junction unit and the first heavily doped region are located between the first PN junction unit and the second PN junction unit; the shallow trench isolation structures are positioned among different well regions, among different PN junction units and among the PN junction units; the first PN junction unit is connected with a high level, the second PN junction unit is connected with a low level, and the third PN junction unit is electrically connected with a heavily doped region with the same conductivity type in the first heavily doped region. Optionally, in the low-voltage SCR device, the first PN junction unit comprises an N-type doped second heavily doped region and a P-type doped third heavily doped region positioned on the right side of the second heavily doped region, and the shallow trench isolation structure is arranged between the second heavily doped region and the third heavily doped region. Optionally, in the low-voltage SCR device, the second PN junction unit comprises a fourth heavily doped region with N type doping and a fifth heavily doped region with P type doping, wherein the fifth heavily doped region is positioned on the right side of the fourth heavily doped region, and the shallow trench isolation structure is arranged between the fourth heavily doped region and the fifth heavily doped region. Optionally, in the low-voltage SCR device, the third PN junction unit comprises a sixth heavily doped region doped with N type and a seventh heavily doped region doped with P type, wherein the seventh heavily doped region is positioned on the right side of the sixth heavily doped region and keeps a space with the sixth heavily doped region. Optionally, in the low-voltage SCR device, in the third PN junction unit, the sixth heavily doped region and the seventh heavily doped region are located in the same active region. Optionally, in the low-voltage SCR device, the first heavily doped region is a P-type heavily doped region or an N-type heavily doped region. Optionally, in the low-voltage SCR device, when the first heavily doped region is a P-type heavily doped region, the third PN junction unit is located in the first well region, the first heavily doped region is located in the second well region, and the seventh heavily doped region in the third PN junction unit is electrically connected to the first heavily doped region. Optionally, in the low-voltage SCR device, when the first heavily doped region is an N-type heavily doped region, the first heavily doped region is located in the first well region, the third PN junction