Semiconductor device and preparation method thereof

The invention discloses a semiconductor device and a preparation method thereof, and the semiconductor device comprises a substrate layer; the epitaxial layer is located on the substrate layer and comprises an active region and a terminal region surrounding the active region; the field limiting rings are arranged in the terminal region of the epitaxial layer at intervals; the junction termination extension regions are located in the terminal region at intervals, the depth of the junction termination extension regions is smaller than that of the field limiting rings, and at least part of the junction termination extension regions are located among the field limiting rings; the epitaxial layer between the adjacent junction termination extension regions forms a current cut-off region, and the conduction type of the current cut-off region is opposite to the conduction type of the field limiting rings and the junction termination extension regions. The semiconductor device is high in reliability and stability. 一种半