Oxygen diffusion blocking semiconductor capacitor

Abstract

Provided is a semiconductor memory device in which defective contact, deterioration in transistor characteristics and other problems are solved with a thermally stable, conductive diffusion barrier layer against oxygen, and against constituent elements in a plug material and a lower electrode, formed at the interface between a plug and the lower electrode made of a noble metal. The semiconductor memory device comprises a dielectric capacitor of a stacked structure including a first electrode (a lower electrode), a dielectric film and a second electrode (an upper electrode) and a conductive plug connected to the lower electrode, wherein the lower electrode connected to the conductive plug includes a metal suboxide layer with conductiveness and a diffusion barrier layer blocking diffusion of oxygen, and the metal suboxide layer and the diffusion barrier layer are stacked in the order from the conductive plug side of the lower electrode.