A 3D semiconductor device, the device including: first transistors; second transistors, overlaying the first transistors; third transistors, overlaying the second transistors; and fourth transistors, overlaying the third transistors, where the second transistors, the third transistors and the fourth transistors are self-aligned, being processed following the same lithography step, and where at least one of the first transistors is part of a control circuit controlling at least one of the second transistors, at least one of the third transistors and at least one of the fourth transistors.