Shielded gate field effect transistor with improved inter-poly dielectric

摘要

A field effect transistor (FET) includes a trench extending into a silicon region of a first conductive type. A shield insulated from the silicon region by a shield dielectric extends in a lower portion of the trench. A gate electrode is in the trench over but insulated from the shield electrode by an inter-poly dielectric (IPD). The IPD comprises a conformal layer of dielectric and a thermal oxide layer.