A semiconductor device, the device comprising: a plurality of transistors, wherein at least one of said plurality of transistors comprises a first single crystal source, channel, and drain, wherein at least one of said plurality of transistors comprises a second single crystal source, channel, and drain, wherein said second single crystal source, channel, and drain is disposed above said first single crystal source, channel, and drain, wherein at least one of said plurality of transistors comprises a third single crystal source, channel, and drain, wherein said third single crystal source, channel, and drain is disposed above said second single crystal source, channel, and drain, wherein at least one of said plurality of transistors comprises a fourth single crystal source, channel, and drain, and wherein said third single crystal channel is self-aligned to said fourth single crystal channel being processed following the same lithography step.