US Patent 10304851 Semiconductor memory device

A semiconductor memory device includes a first semiconductor well of a first conductivity type in a memory cell region and a contact region of a substrate, a second semiconductor well of a second conductivity type in the first semiconductor well in the contact region, a plurality of electrode films stacked on the first semiconductor well and spaced from one another in a first direction, the plurality of electrode films extending in a second direction within the memory cell region into the contact region, a first semiconductor pillar extending in the second direction through the plurality of electrode films in the memory cell region, a second semiconductor pillar extending in the second direction through at least one electrode film in the contact region, a charge storage film between the first semiconductor pillar and each electrode film, an insulating film between the second semiconductor pillar and the at least one electrode film.