Semiconductor device and method for manufacturing semiconductor device

Abstract

The present application relates to a semiconductor device and a method for preparing the semiconductor device. The semiconductor device comprises: a substrate; an epitaxial layer, which is arranged on one side of the substrate, and a first groove is arranged on the surface of the epitaxial layer facing away from the substrate; a gate, which is at least partially located in the first groove; a first oxide layer, which is located at the bottom of the first groove, and the first oxide layer comprises a planar portion and a curved portion connected to the edge of the planar portion, the curved portion is arranged toward the gate, and the corners of the gate and the curved portion are matched and connected; a gate dielectric layer, which is arranged on the sidewall of the gate, and the thickness of the first oxide layer is greater than that of the gate dielectric layer. The first oxide layer at the bottom of the first groove and the gate corner position are smoothed, the peak electric field strength at the corner position is reduced, the breakdown resistance of the device is improved, and the reliability of the device is improved.

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