Stacked MOS device with means to prevent substrate floating

Claim 1

An MOS type semiconductor device comprising: a. a semiconductor substrate of a first conducting type; b. a first MOS transistor formed on a portion of said semiconductor substrate; c. an insulating layer formed on said first MOS transistor and on a portion of said substrate, said insulating layer having an opening to said substrate; and d. a second MOS transistor formed on said insulating layer at least in part over said first MOS transistor, said second MOS transistor comprising a source region of a second conductivity type completely separated from said substrate by said insulating layer, a drain region of said second conductivity type spaced from said source region and completely separated from said substrate by said insulating layer, and a channel region of said first conductivity type located between said source and drain regions and over said opening in said insulating layer and contacting said substrate through said opening.