US Patent 7732891 Semiconductor device

A semiconductor device has a substrate, a source region formed on the surface portion of the substrate, a first insulating layer formed on the substrate, a gate electrode formed on the first insulating layer, a second insulating layer formed on the gate electrode, a body section connected with the source region, penetrating through the first insulating layer, the gate electrode and the second insulating layer, and containing a void, a gate insulating film surrounding the body section, and formed between the body section and the gate electrode, and a drain region connected with the body section.