US Patent 9997598 Three-dimensional semiconductor device and method of fabrication

A semiconductor device including a substrate and a gate region of a field effect transistor formed on the substrate. The gate region includes vertically stacked nanowires having longitudinal axes that extend parallel with a working surface of the substrate. A given stack of vertically stacked nanowires includes at least two nanowires vertically aligned in which a p-type nanowire and an n-type nanowire are spatially separated from each other vertically. The semiconductor device further includes a step-shaped connecting structure formed within the gate region that electrically connects each nanowire to positions above the gate region. A first gate electrode has a step-shaped profile and connects to a first-level nanowire.