PNPNP type triac

Abstract

The invention discloses a PNPNP type triac which comprises a P type substrate, wherein an N type buried layer is arranged in the P type substrate, a P well is injected on the N type buried layer, an annular N well in the junction depth which is the same with that of the P well is injected between the side surface of the P well and the P type substrate, a first N type drift region and a second N type drift region are injected in the P well, a first P+ injection region and a first N+ injection region are arranged in the first N type drift region, and a second P+ injection region and a second N+ injection region are arranged in the second N type drift region, wherein the first P+ injection region and the second P+ injection region are positioned on the inner side, and oxidation and isolation layers are covered on the P type substrate, the N well and the P well. The PNPNP type triac structure can realize the compatibility of the process with the commonly used BCD process in the industry; as the PNPNP type triac structure has higher and symmetric forward and reverse breakdown voltage, the PNPNP type triac is more applicable to ESD protection application of a plurality of mixed voltage interface circuits or among different power domains.

Description

technical field [0001] The invention relates to the field of integrated circuits, in particular to a PNPNP bidirectional thyristor. Background technique [0002] The electrostatic discharge (ESD) phenomenon in nature is one of the most important reliability problems that cause the failure of integrated circuit products. Relevant research surveys show that 30% of integrated circuit failure products are caused by electrostatic discharge phenomena. Therefore, improving the reliability of electrostatic discharge protection on integrated circuits has a non-negligible effect on improving the yield of integrated circuit products and even driving the entire national economy. [0003] Electrostatic discharge phenomenon is usually divided into three discharge modes according to the source of charge: HBM (Human Body Discharge Model), MM (Machine Discharge Mode), and CDM (Component Charge Discharge Mode). The two most common electrostatic discharge modes that industrial products must ...

AI Technical Summary

Problems solved by technology

[0006] like Figure 1~4 As shown, an SCR structure under the CMOS process, the trigger voltage of the SCR in one direction is higher, and it works in the form of SCR after triggering, while the trigger voltage in the other direction is lower (generally, the conduction voltage of the forward diode On-voltage), so the SCR structure is difficult to apply to the ESD protection of some mixed voltage interface circuits (such as RS232, etc.)

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