A method for making a power MOSFET includes forming a trench in a semiconductor
layer, forming a gate dielectric layer lining the trench, forming a gate conducting
layer in a lower portion of the trench, and forming a dielectric layer to fill
an upper portion of the trench. Portions of the semiconductor layer laterally adjacent
the dielectric layer are removed so that an upper portion thereof extends outwardly
from the semiconductor layer. Spacers are formed laterally adjacent the outwardly
extending upper portion of the dielectric layer, the spacers are used as a self-aligned
mask for defining source/body contact regions.
