Semiconductor memory device having pillar structures

Abstract

A semiconductor memory device includes first and second active pillar structures protruding at an upper part of a substrate, buried bit lines each extending in a first direction, and first gate patterns and second gate patterns each extending in a second direction. The first and second active pillar structures occupy odd-numbered and even-numbered rows, respectively. The first and the second active pillar structures also occupy even-numbered and odd-numbered columns, respectively. The columns of the second active pillar structures are offset in the second direction from the columns of the first active pillar structures. Each buried bit line is connected to lower portions of the first active pillar structures which occupy one of the even-numbered columns and to lower portions of the second active pillar structures which occupy an adjacent one of the odd-numbered columns.