A 3D semiconductor device, the device including: a first level including a first single crystal layer, the first level including first transistors, where each of the first transistors includes a single crystal channel; a first metal layer; a second metal layer overlaying the first metal layer; a second level including second transistors, first memory cells including at least one second transistor, and overlaying the second metal layer, a third level including third transistors and overlaying the second level, a fourth level including fourth transistors, second memory cells including at least one fourth transistor, and overlaying the third level, where the first level includes memory control circuits which control writing to the second memory cells, and at least one Phase-Lock-Loop (“PLL”) circuit or at least one Digital-Lock-Loop (“DLL”) circuit.