Lateral double-diffused transistor and manufacturing method thereof

Abstract

The invention discloses a lateral double-diffused transistor and a manufacturing method thereof. The lateral double-diffused transistor comprises a substrate, a well region and a drift region which are located at the top of the substrate, a source region and a drain region which are located in the well region and the drift region respectively, a first dielectric layer located on a surface of the drift region, a first field plate which is located on a surface of the drift region and covers a part of a surface of the first dielectric layer, a second dielectric layer which partially covers the surface of the first field plate and is stacked on a part of the surface of the first dielectric layer, and a second field plate positioned on a surface of the second dielectric layer, wherein the second field plate comprises at least one contact channel. The lateral double-diffusion transistor is advantaged in that a contact channel is used as the second field plate, so the manufacturing process isreduced, a distance between the second field plate and the silicon substrate is increased, a breakdown voltage of the transistor is increased, and the-powered-on resistance is reduced.

Description

technical field [0001] The present invention relates to the technical field of semiconductors, in particular to a lateral double-diffused transistor and a manufacturing method thereof. Background technique [0002] The power field effect transistor is an important transistor. The power field effect transistor mainly includes a vertical diffused MOS (Vertical Diffused Metal Oxide semiconductor, VDMOS) transistor and a lateral diffused MOS (Lateral Double-Diffused MOSFET, LDMOS) transistor. Compared with VDMOS transistors, LDMOS transistors have many advantages, such as compatibility with planar CMOS (Complementary Metal Oxide Semiconductor, Complementary Metal Oxide Semiconductor) process, better thermal stability and frequency stability, higher gain, and lower feedback Capacitance and thermal resistance, as well as constant input impedance, are therefore widely used. [0003] In the application of lateral double-diffused transistor (LDMOS), it is required to reduce the sou...

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Problems solved by technology

[0004] The VDMOS device in the prior art forms a single field plate on the surface of the dielectric layer, the distance between the field plate and the semiconductor surface is constant, and the thickness of the oxide dielectric layer is uniform, which cannot simultaneously meet the high turn-off breakdown voltage (off-BV) and Lower on-resistance (Rdson) requirements, resulting in poorer transistor performance

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