A method for manufacturing a monolithic three-dimensional (3D) integrated circuit (IC) with junctionless semiconductor devices (JSDs) is provided. A first interlayer dielectric (ILD) layer is formed over a semiconductor substrate, while also forming first vias and first interconnect wires alternatingly stacked in the first ILD layer. A first doping-type layer and a second doping-type layer are transferred to a top surface of the first ILD layer. The first and second doping-type layers are stacked and are semiconductor materials with opposite doping types. The first and second doping-type layers are patterned to form a first doping-type wire and a second doping-type wire overlying the first doping-type wire. A gate electrode is formed straddling the first and second doping-type wires. The gate electrode and the first and second doping-type wires at least partially define a JSD.