Stacked transistor device

Logic devices and methods of forming logic devices are described. An epitaxial channel is formed orthogonally to a horizontal plane of a substrate surface with a stack or horizontal transistors on the substrate surface. The first horizontal transistor having a first length and a first step, the second horizontal transistor having a second length and a second step and a third horizontal transistor has a third length and a third step. Each of the horizontal transistors is separated from adjacent layers by a horizontal isolation layer.