Parasitic lateral pnp transistor and manufacturing method thereof

Abstract

A parasitic lateral PNP transistor is disclosed, in which, an N-type implanted region formed in each of two adjacent active regions forms a base region; a P-type doped polysilicon pseudo buried layer located under a shallow trench field oxide region between the two active regions serves as an emitter; and a P-type doped polysilicon pseudo buried layer located under each of the shallow trench field oxide regions on the outer side of the active regions serves as a collector region. The transistor has a C-B-E-B-C structure which alters the current path in the base region to a straight line, which can improve the current amplification capacity of the transistor and thus leads to a significant improvement of its current gain and frequency characteristics, and is further capable of reducing the area and increasing current intensity of the transistor. A manufacturing method of the parasitic lateral PNP transistor is also disclosed.