Laterally diffused metal oxide semiconductor field effect transistor with RESURF (reduced surface field) structure

Abstract

The present invention relates to a laterally diffused metal oxide semiconductor field effect transistor with an RESURF (reduced surface field) structure. The laterally diffused metal oxide semiconductor field effect transistor includes a substrate, a gate, a source, a drain, a body region, a field oxide region which is located between the source and the drain, as well as a first well region and a second well region which are located on the substrate; a plurality of gate doped regions are arranged in the second well region below the gate; the polysilicon gate of the gate is of a multi-section structure; the sections of the polysilicon gate are separated from one another; the gate doped regions are arranged below gaps between the sections of the polysilicon gate; and each gate doped region is electrically connected with one of two sections of the polysilicon gate which are located at two sides of the gate doped region, wherein the one section of the polysilicon gate electrically connected with the gate doped region is adjacent to the source. According to the laterally diffused metal oxide semiconductor field effect transistor with the RESURF structure of the invention, the number of trench electrons is increased, and the electrons are accelerated a plurality of times during a process of flowing from the source to the drain, equivalently, and a trench electric field and trench current can be improved, and therefore, trench resistance is reduced, and on-resistance can be reduced.

Description

technical field [0001] The invention relates to a semiconductor process, in particular to a lateral diffusion metal oxide semiconductor field effect transistor with a RESURF structure. Background technique [0002] The basic structure using the principle of RESURF (reduced surface electric field) consists of a low-doped P-type substrate and a low-doped N-type epitaxial layer. Form a P well on the epitaxial layer and inject N+ and P+ to form a horizontal P-well / N-epi junction and a vertical P-sub / N-epi junction. Due to the higher doping concentration at both ends of the lateral junction, the breakdown voltage is lower than that of the vertical junction. The basic principle of RESURF is to use the interaction between the lateral junction and the vertical junction to completely deplete the epitaxial layer before the lateral junction reaches the critical avalanche breakdown electric field. Reduce the effect of the surface electric field. [0003] To improve the on-resistance ...

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Problems solved by technology

However, since the doping concentration is inversely proportional to the off-state breakdown, improving the on-resistance only by improving the drift region resistance Rdr has its limitations.

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