| abstract |
The invention discloses a method for preparing a trench MOSFET device, which is included in a semiconductor substrate, and a mask is used to simultaneously prepare a narrow trench and a wide trench, so as to define the narrow trench and the wide trench. An insulating layer with a first portion that fills the narrow trench and a second portion that partially fills the wide trench. The second portion is completely removed from the wide trench, and the narrow trench filled with the first part is retained to prepare a gate. Electrode, a body region is prepared on the top of the semiconductor substrate, an insulation region is prepared in a part of the body region, a first portion of the nitride is removed from the narrow trench, and a second conductive material in the narrow trench is filled to prepare a Touch the plug. |