The invention relates to an
MOSFET device with a
silicon carbide single-side deep L-shaped base region structure and a preparation method of the
MOSFET device. The
MOSFET device comprises a
gate dielectric layer, a base region which comprises a first base region and a second base region located on the two sides of the
gate dielectric layer respectively, a current
diffusion layer located between the
gate dielectric layer and the second base region, a drift layer located on the lower surfaces of the base region and the current
diffusion layer, a substrate layer located on the lower surface of the drift layer, a drain
electrode located on the lower surface of the substrate layer, a
polycrystalline silicon layer positioned on the inner surface of the gate
dielectric layer, a gate
electrode located on the upper surface of the
polycrystalline silicon layer, a first source region located on the upper surface of a preset region of the base region, a
second source region located on the upper surface of the rest region of the base region, and a source
electrode located on the upper surfaces of the first source region and the
second source region. According to the MOSFET device, by changing the structure of the single-side P-type base region, under the condition that the
cell area of the device is not enlarged, the
electric field aggregation at the groove-gate corner is reduced, and the
breakdown voltage of the device is improved.