US Patent 9997413 Stacked vertical devices

A semiconductor structure containing a plurality of stacked vertical field effect transistor (FETs) is provided. After forming a first vertical FET of a first conductivity type at a lower portion of a semiconductor fin, a second vertical FET of a second conductivity type is formed on top of the first vertical FET. The second conductivity type can be opposite to, or the same as, the first conductivity type. A source/drain region of the first vertical FET is electrically connected to a source/drain region of the second vertical FET by a conductive strip structure.