Groove MOSFET device and manufacturing method thereof

Abstract

The invention provides a groove MOSFET device and a manufacturing method thereof. The manufacturing method includes the steps that a substrate with an epitaxy layer is provided; a groove is formed in the epitaxy layer; a first insulating layer, a first gate electrode, a second insulating layer and a second gate electrode are sequentially formed in the groove through deposition and etching; ions are ejected into the two sides of the groove to form a well region and a source electrode region; groove type contact regions and a metal connector are formed. By means of the manufacturing method, the first gate electrode and the second gate electrode are separated, the thickness of the first insulating layer between the lower portion of the first gate electrode and the epitaxy layer is large, the thickness of the second insulating layer between the second gate electrode and the well region and between the second gate electrode and the source electrode region is small, and the two separated gate electrodes are connected through the metal connector, so that the device is good in high voltage resistance while the threshold voltage of the device is low. The device is stable in performance, simple in preparing method and low in preparing cost.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a trench MOSFET device and a manufacturing method thereof. Background technique [0002] MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor, Metal-Oxide-Semiconductor Field Effect Transistor) parameters such as response speed, switching current ratio, and threshold voltage all affect the performance of the final device. In order to improve the response speed of the MOSFET transistor, the switching current ratio and reduce the threshold voltage of the MOSFET transistor, the thickness of the gate oxide layer needs to be continuously reduced. However, the thinner the gate oxide layer is, the easier it is to be broken down by the charge accumulated in the gate electrode at a higher gate voltage, thus causing damage to the MOSFET transistor. [0003] In order to make the MOSFET transistor have better withstand voltage performance under the premise of high r...

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Problems solved by technology

However, this structure requires very good insulation between the gate 7 and the polysilicon protection electrode 6, which not only increases the difficulty of the process, but also is not conducive to ensuring the high-voltage resistance of the device, resulting in poor stability of the device, and The device process steps for manufacturing this structure are complicated and the manufacturing cost is high

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