LDMOS device and forming method thereof

Abstract

The invention discloses an LDMOS device and a forming method thereof. The LDMOS device comprises a semiconductor substrate, a drift region, a shallow trench isolation structure, a doping layer, a gate structure, a source region and a drain region. A well region is located in the semiconductor substrate. The drift region is located in the well region, and the doping type of the drift region is opposite to the doping type of the well region. The shallow trench isolation structure is placed in the drift region, and the depth of the shallow trench isolation structure is smaller than the depth of the drift region. The doping layer is placed at the bottom of the shallow trench isolation structure, and the doping type of the doping layer is opposite to the doping type of the drift region. The gate structure is placed on the semiconductor substrate, one end of the gate structure extends to the position above the well region, and the other end of the gate structure extends to the position above the shallow trench isolation structure. The source region is located in the well region on one side of the gate structure, and the drain region is located in the drift region on the other side of the gate structure. The breakdown voltage of the LDMOS device is kept unchanged, and meanwhile drive currents are increased.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to an LDMOS device and a forming method thereof. Background technique [0002] Power field effect transistors mainly include two types: vertical double-diffused field effect transistor VDMOS (Vertical Double-Diffused MOSFET) and lateral double-diffused field effect transistor LDMOS (Lateral Double-Diffused MOSFET). Among them, compared with the vertical double diffused field effect transistor VDMOS, the lateral double diffused field effect transistor LDMOS has many advantages, for example, the latter has better thermal stability and frequency stability, higher gain and durability, lower Feedback capacitance and thermal resistance, as well as constant input impedance and simpler bias current circuit. [0003] Drive current (Ion) and breakdown voltage BV (Breakdown Voltage) are two important parameters to measure the performance of LDMOS devices. Among them, the driving cu...

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Problems solved by technology

[0005] The larger breakdown voltage and larger driving current make the LDMOS device have better switching characteristics and stronger driving capability, but it is difficult for the existing LDMOS device to meet the above two conditions at the same time

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