High-voltage asymmetric structure LDMOS device and preparation method thereof

Abstract

The invention provides a high-voltage asymmetric structure LDMOS device and a preparation method thereof. The LDMOS device comprises a drift region and a body region, the surface of the drift region is divided into a first region and a second region; the surface of the body region is divided into a third region and a fourth region, and the second region and the fourth region are extended and covered by a first gate dielectric layer; the surface of the first gate dielectric layer is divided into a seventh region, and the seventh region is located above the drift region and is covered by a second gate dielectric layer; the surface of the second gate dielectric layer is divided into a sixth region and a fifth region, and the first gate dielectric layer outside the fifth region and the seventhregion is covered by a polysilicon gate in an extending manner; a drain region is formed in the first region of the drift region from the surface to the inside; a source region is formed in the thirdregion of the body region from the surface to the inside, and the drain region is deeper than the source region. And the double-layer gate dielectric structure ensures the working reliability of thedevice under the conditions of high voltage and high current. The junction depth of the drain region is greater than that of the source region, thereby effectively improving the control capability ofthe drain region for a conductive channel.

Description

technical field [0001] The invention relates to the technical field of semiconductor integrated circuits, in particular to a high-voltage asymmetric structure LDMOS device and a preparation method of a high-voltage asymmetric structure LDMOS device. Background technique [0002] With the development of the times, power semiconductor devices have penetrated into all aspects of national economic life. In recent years, energy conservation and environmental protection have become a topic of increasing concern worldwide, and the application fields of semiconductors have also expanded from traditional industrial control, communications, computers, and consumer electronics to new fields such as new energy, smart grids, rail transit, and automotive electronics. The pursuit of power semiconductor devices is the processing of electric energy, which is required to have high withstand voltage and high current characteristics. [0003] LDMOS (Lateral Double-Diffused MOSFET), as a latera...

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Problems solved by technology

The design of LDMOS is mainly carried out around the reasonable compromise between the breakdown voltage and the characteristic on-resistance. Increasing the device withstand voltage by increasing the length of the drift region will lead to a sharp increase in the device on-resistance

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