SEMICONDUCTOR MEMORY DEVICE HAVING VERTICAL TRANSISTOR AND BURIED BIT LINE AND METHOD FOR FABRICATING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a semiconductor memory device with a simple fabrication process, in which an ohmic contact is formed between a drain region of a vertical transistor and a buried bit line, and a method for fabricating the same.

SOLUTION: A semiconductor memory device includes: an active region protruding upward from a substrate by a trench formed on the substrate; a first impurity region formed at an upper portion of the active region; a second impurity region formed at a lower portion of the active region; a gate dielectric layer formed along a side of the active region between the first impurity region and the second impurity region; a gate electrode layer formed on the gate dielectric layer; and a buried bit line consisting of a metal layer disposed apart from the second impurity region by a liner layer below the trench and a polysilicon layer disposed so as to directly contact the second impurity region over the metal layer.

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