A semiconductor device including: a first single crystal layer including first transistors, first alignment mark, and at least one metal layer, the at least one metal layer overlying the first single crystal layer and includes copper or aluminum; and a second layer overlying the metal layer; the second layer includes second transistors which include mono-crystal and are aligned to the first alignment mark with less than 40 nm alignment error, the mono-crystal includes a first region and second region which are horizontally oriented with respect to each other, the first region has substantially different dopant concentration than the second region.