The invention discloses a multi-dimensional doped profile optimized ultrathin body
MOSFET device and a preparation process thereof, and belongs to the technical field of
semiconductor devices, the multi-dimensional doped profile optimized ultrathin body
MOSFET device comprises a plurality of MOS cells which are parallel to one another, and each MOS
cell comprises a drain
electrode, a
semiconductor epitaxial layer, a source
electrode and a grid
electrode; the
semiconductor epitaxial layer comprises an N substrate layer, an N drift layer, a P + layer, an N well layer and a P well layer, a lightly doped N layer is arranged in the middle of the N drift layer of a single MOS
cell, side symmetric P-
layers are arranged in the single MOS
cell and located on the left side and the right side of the N drift layer, the side symmetric P-
layers are of rectangular outlines, and the top ends of the side symmetric P-
layers make contact with the grid electrode; in the first embodiment, the laterally symmetrical P-layer and the N drift layer form a PN junction, a transverse
depletion region is generated during
reverse bias, the transverse
electric field range is expanded, and local
electric field concentration is avoided.