High-voltage asymmetric structure ldmos device and its preparation method

Abstract

The invention provides a high-voltage asymmetric structure LDMOS device and a preparation method thereof. The LDMOS device includes: 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 divided by the first gate The dielectric layer is extended and covered; 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 covered by the second gate dielectric layer; the surface of the second gate dielectric layer is divided into a sixth region and a fifth region , the first gate dielectric layer outside the fifth region and the seventh region is covered by the polysilicon gate extension; the first region of the drift region forms a drain region from the surface inward; the third region of the body region forms an active region from the surface inward , the depth of the drain region is greater than the depth of the source region. The double-layer gate dielectric structure ensures the reliability of the device under high-voltage and high-current conditions. The junction depth of the drain region is greater than the junction depth of the source region, which effectively improves the ability of the drain region to control the 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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