MOSFET device for automobile air conditioner speed regulation module

The utility model relates to a metal oxide semiconductor field effect transistor (MOSFET) device for a speed regulation module of an automobile air conditioner, which is characterized in that an N + type epitaxial layer is arranged on the back of an N-type substrate, and a back metal layer is arranged on the back of the N + type epitaxial layer; an N + type electric field cut-off ring is arranged on the outermost periphery of the front face of the N-type substrate, a regular hexagonal P + type well region is arranged on the front face of the N-type substrate corresponding to the inner side of the N + type electric field cut-off ring, and an N + type source region is arranged on the front face of the P + type well region. Gate oxide layers are arranged on the front face of part of the P + type well region, the front face of part of the N + type source region and the front face of the N-type substrate between the P + type well region and the N + type electric field cut-off ring, a polycrystalline silicon layer