US Patent 8212298 Semiconductor storage device and methods of producing it

A semiconductor storage device where one MOS transistor in a memory cell section includes a selection transistor, and one MOS transistor in a peripheral circuit section includes a first MOS transistor and a second MOS transistor of different conductivity type, the first MOS and second MOS transistors and the selection transistor include lower drain or source regions in a planar semiconductor layer, a pillar-shaped semiconductor layer on the planar semiconductor layer, upper source or drain regions in an upper portion of the pillar-shaped semiconductor layer, and a gate electrode that surrounds a sidewall of the pillar-shaped semiconductor layer through a dielectric film, and where a first silicide layer connects a surface of the lower drain or source region of the first MOS and second MOS transistors, and a second silicide layer on a surface of the lower drain or source region of the selection transistor.