Abstract

A ferroelectric memory device of an MFIS FET structuring using a yttrium oxide film as a buffer film and a manufacturing method of the memory device are provided. The MFIS FET includes a p-type silicon substrate, a field oxide film formed in a device isolation region of the silicon substrate, a gate yttrium oxide film formed on the surface of the silicon substrate, a gate ferroelectric film formed on the gate yttrium oxide film, a gate TiN electrode formed on the gate ferroelectric film, and an n-type source/drain region formed in the silicon substrate of both sides of the gate TiN electrode. In this way, single crystals of the gate yttrium oxide film are easily formed resulting in the formation of a good-quality ferroelectric film on the yttrium oxide film.