Power device and preparation method therefor

Abstract

The invention provides a power device, and the power device includes a substrate, an epitaxial layer formed on the substrate, body regions formed in the epitaxial layer, source regions formed in the body regions, channel regions between the body regions and the source regions, a drift region between the body regions, first silicon oxide layers formed on the epitaxial layer, a silicon oxynitride layer formed between the first silicon oxide layers, semi-insulating polysilicon layers which are formed on the upper surfaces of the first silicon oxide layers and the silicon oxynitride layer, secondsilicon oxide layers formed on the semi-insulating polysilicon layers, and polysilicon layers formed on the upper surfaces of the second silicon oxide layers. The first silicon oxide layers are located on the upper surfaces of the channel regions and the source regions, and a projection region of the silicon oxynitride layer in a direction perpendicular to the upper surface of the substrate is included in the projection region of the drift region. The invention also provides a method for preparing the power device, which reduces conduction loss and parasitic capacitance, and improves the switching speed.

Description

technical field [0001] The invention relates to the technical field of semiconductor chip manufacturing technology, in particular to a power device and a preparation method thereof. Background technique [0002] The drain and source poles of the vertical double diffused field effect transistor (VDMOS) are respectively on both sides of the device, so that the current flows vertically inside the device, increasing the current density, improving the rated current, and the on-resistance per unit area is also small, which is a A very versatile power device. The most important performance parameter of the vertical double-diffused field effect transistor is the operating loss, which can be divided into three parts: conduction loss, cut-off loss and switching loss. The conduction loss is determined by the conduction resistance, the cut-off loss is affected by the reverse leakage current, and the switching loss refers to the loss caused by the charging and discharging of parasitic c...

AI Technical Summary

Problems solved by technology

Since a large part of the conduction loss is caused by the gate leakage of the power device, the gate of the power device needs to withstand a certain operating voltage in the working state, and the gate leakage will increase the conduction of the power device. In addition to loss, it will also affect the reliability of power devices

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