Ldmos device with circular symmetrical structure and its preparation method

Abstract

The invention provides an LDMOS device with a circular symmetrical structure and a preparation method thereof, comprising: a substrate, a gate dielectric layer and a gate electrode; the substrate is divided into a first region, and a high-voltage well region is formed in the first region; the first region Including the second region and the third region; the second region is formed with a body region, the third region is formed with a drift region, and the drift region and the body region are located in the high voltage well region; the second region includes a fourth region and a fifth region, and the fourth The source region is formed by ion implantation in the region; the third region includes the sixth region and the seventh region; the drain region is formed in the seventh region by ion implantation; the gate dielectric layer is formed above the fifth region and the sixth region; the gate dielectric layer includes thin oxide region and the field oxygen region; the surface of the field oxygen region is divided into an eighth region; the gate electrode is arranged on the eighth region and the thin oxygen region. The central symmetrical layout is adopted to eliminate process gradient errors and improve the yield, uniformity and consistency of the mass production process; the circular field plate structure is adopted to improve the breakdown voltage and reliability of the device.

Description

technical field [0001] The invention relates to the technical field of semiconductor integrated circuits, in particular to an LDMOS device with a circular symmetrical structure and a method for preparing the LDMOS device with a circular symmetrical structure. Background technique [0002] As a power switching device, MOSFET has the advantages of low power consumption, fast speed, and simple driving, and is widely used in power integrated circuits. In the semiconductor industry, MOSFET occupies a considerable market share. In 2011, only power MOS in the domestic market accounted for nearly 30% of the market share. Since the source, drain and gate of the lateral power MOS are on the surface of the device, it is easy to integrate with other devices or circuits on a chip. This is the biggest advantage that lateral power devices have over vertical power devices. [0003] Because MOSFETs in digital circuits or analog circuits do not need to withstand a large withstand voltage, t...

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Problems solved by technology

The manufacturing process of such a field plate is obviously complicated

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