MOS type power device and preparation method thereof

The invention provides a MOS type power device and a preparation method thereof. A MOS-type power device comprises a substrate; a Well region; a Source region; a Gate oxide layer; a Gate electrode; anInsulating dielectric layer; A source region electrode, wherein a lower surface of the well region is provided with a protrusion extending downward. Thus, the MOS type power device has a well depth deep enough, sufficient withstand voltage margin can be ensured, At the same time, it has enough short channel and lower saturation voltage drop to increase channel density and reduce channel short-circuit current, effectively reduce on-resistance and improve short-circuit safety ability, fully ensure the reliability of device application, and has quasi-channel current self-pinch-off function to enhance the high-voltage and large-current shutdown ability of the device. 本发明提供了MOS型功率器件及其制备方法。所述MOS型功率器件包括：衬底；阱区；源区；栅氧化层；栅电极；绝缘介质层；源区电极，其中，阱区的下表面设置有向下延伸的凸起部。由此，该MOS型功率器件具有足够深的阱深，可以保证充足的耐压余量，同时具有足够短的沟道，更低的饱和压降，达到增大沟道密度和减小沟道短路电