Techniques and mechanisms for operating transistors that are in a stacked configuration. In an embodiment, an integrated circuit (IC) device includes transistors arranged along a line of direction which is orthogonal to a surface of a semiconductor substrate. A first epitaxial structure and a second epitaxial structure are coupled, respectively, to a first channel structure of a first transistor and a second channel structure of a second transistor. The first epitaxial structure and the second epitaxial structure are at different respective levels relative to the surface of the semiconductor substrate. A dielectric material is disposed between the first epitaxial structure and the second epitaxial structure to facilitate electrical insulation of the channels from each other. In another embodiment, the stacked transistors are coupled to provide a complementary metal-oxide-semiconductor (CMOS) inverter circuit.