Memory element with small threshold voltage variance and high-speed logic element with low power consumption

Abstract

A semiconductor device includes: a semiconductor layer; an element isolation region formed in the semiconductor layer for separation between a memory element part and a logic element part; first and second field-effect transistors formed in the memory element part and having first and second gate electrodes on a first surface side of the semiconductor layer and a second surface side opposite to the first surface, respectively, and having a source and drain region in common with each other; a third field-effect transistor formed in the logic element part and having a third gate electrode on the second surface side; and first and second insulating films formed on the semiconductor layer to cover the first field-effect transistor and the second and third field-effect transistors, respectively. The first field-effect transistor and the second field-effect transistor are fully-depleted field-effect transistors. The first gate electrode and the second gate electrode are electrically connected.