Semiconductor memory device

Abstract

A semiconductor memory device including a first MIS transistor having source and drain regions formed in a substrate and a gate electrode provided on the substrate through an insulating layer; a semiconductor layer provided on the first MIS transistor through the insulating layer and being in contact with the source and drain regions of the first MIS transistor; a second MIS transistor having source and drain regions formed in the semiconductor layer and being in contact with the source and drain regions of the first MIS transistor and having a gate electrode provided on the semiconductor layer through an insulating layer; and a bit line being in contact with the source or drain region of the second MIS transistor and extended on the second MIS transistor; each gate electrode of the first and the second MIS transistors being connected with different word lines respectively, and impurities having an amount more than a required value being doped to at least one of the substrate and the semiconductor layer below the gate electrode of the first MIS transistor and the semiconductor.

Dependencies are inferred from the claim text.