| 摘要 |
A trench type MOSFET and a manufacturing method thereof are provided to improve the degree of integration and to reduce the capacitance by using an improved interlayer dielectric structure. A trench type MOSFET includes a drain electrode, a substrate(15) on the drain electrode, a drain region(20) on the substrate, a body on the drain region, a plurality of source regions(30) on the body, a trench(35), an oxide layer(40) along an inner surface of the trench, a polysilicon gate on the oxide layer, an interlayer dielectric(50) on the polysilicon gate, a source electrode(55) for contacting the source regions, a common gate electrode, and a bus line for connecting the common gate electrode with the polysilicon gate. A first lateral of the interlayer dielectric is consistent with a second lateral of the trench. The upper surface of the interlayer dielectric is higher than that of the body. The interlayer dielectric is made of an undoped oxide layer and a BPSG layer. A bottom corner of the trench is roundly formed.
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