A structure of shielded gate-trench type mosfet and its manufacturing method

Abstract

The invention discloses a shielded gate-groove MOSFET structure and a manufacturing method thereof. The shielded gate-trench MOSFET in the present invention adopts a stepped gate oxide to form a gate dielectric layer, and the stepped gate dielectric layer is an n-level oxide, and the thickness of the oxide from the bottom of the trench to the top of the trench is D1 , D2,..., Dn, wherein, D1>D2>...>Dn. The shielded gate-trench MOSFET structure using the stepped gate oxide as the gate dielectric layer disclosed in the present invention can effectively realize the isolation between the gate and the drain, reduce the gate-to-drain capacitance Cgd, and also make the The MOSFET has a lower specific on-resistance and maintains a high breakdown voltage, which improves the performance of the MOSFET.

Description

technical field [0001] The invention relates to semiconductor technology, and more specifically, to a structure and a manufacturing method of a shielded gate-trench MOSFET. Background technique [0002] Metal-Oxide-Semiconductor Field-Effect Transistors, referred to as Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) are widely used in switching components of power devices, such as power supplies, rectifiers or low-voltage motors controller etc. Existing MOSFETs mostly adopt a vertical structure design, such as trench MOSFETs, to increase device density. Shielded gate metal oxide semiconductor field effect transistors are commonly used in the industry to improve the excessively high gate-drain capacitance in the existing trench MOSFET structure, increase the cut-off voltage of the transistor, and reduce switching losses. [0003] Operating loss is one of the most important performance parameters of power devices. Operating loss mainly includes three aspects: co...

AI Technical Summary

Problems solved by technology

From the above relationship between breakdown voltage and specific on-resistance, it can be seen that if the device can be used in high voltage, a larger breakdown voltage is required. At this time, the specific on-resistance will rise sharply, which will limit some The application of MOSFET devices in high-voltage power integrated circuits, especially in circuits requiring low conduction loss and small chip area

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