Trench gate device and method for making the same

A trench gate device, comprising:

• a substrate with a super junction structure, a trench gate structure formed in the substrate, and an interlayer dielectric layer on the surface of the substrate;
• the trench gate structure comprises a gate dielectric layer covering the bottom and sidewalls of a trench, a polysilicon gate at the inner side of the gate dielectric layer, an intermediate dielectric layer at the inner side of the polysilicon gate, and an auxiliary polysilicon layer at the inner side of the intermediate dielectric layer;
• in the substrate, a source region is formed at the outer side of the trench gate structure;
• contacts are formed in the interlayer dielectric layer, and the polysilicon gate, the auxiliary polysilicon layer, and the source region are respectively led out from the contacts;
• and
• the led-out auxiliary polysilicon layer is connected to the led-out source region.