DUAL RESURF TRENCH FIELD PLATE IN VERTICAL MOSFET

摘要

A semiconductor device contains a vertical MOS transistor with instances of a vertical RESURF trench on opposite sides of a vertical drift region. The vertical RESURF trench contains a dielectric trench liner on sidewalls, and a lower field plate and an upper field plate above the lower field plate. The dielectric trench liner between the lower field plate and the vertical drift region is thicker than between the upper field plate and the vertical drift region. A gate is disposed over the vertical drift region and is separate from the upper field plate. The upper field plate and the lower field plate are electrically coupled to a source electrode of the vertical MOS transistor.