Semiconductor power device and preparation method thereof

The invention provides a semiconductor power device and a preparation method thereof. The semiconductor power device comprises: a plurality of main well regions arranged at intervals in a drift layer; a source region in the main well region; a channel region is arranged in the top region of the main well region, and the channel region is adjacent to the side wall of the source region; the auxiliary well regions and the JFET regions are located in the drift layer between the adjacent main well regions, the auxiliary well regions and the main well regions are spaced, the JFET regions make contact with the side walls, away from the source region, of the channel regions, and the conduction type of the JFET regions is opposite to that of the main well regions; the JFET region comprises a first JFET region located between the auxiliary well region and the main well region; the first JFET region is provided with a first side wall and a second side wall which are opposite to each other, the first side wall is in cont