A device, including: a first structure including first memory cells, the first memory cells including first transistors; and a second structure including second memory cells, the second memory cells including second transistors, where the second transistors overlay the first transistors, and a plurality of memory cells control lines, where the first transistors are self-aligned to the second transistors, where a second transistor channel of the second transistors is aligned to a first transistor channel of the first transistors, the aligned is at an atomic level as would have been resulted from an epitaxial growth process.