Semiconductor device and manufacturing method thereof

摘要

It is the object to provide a semiconductor device capable of preventing ohmic resistance between a tungsten plug and a metallic electrode from increasing even if an oxide film is formed on the tungsten plug. The tungsten plug 13 is formed in the reducing atmosphere on a P-type substrate 3. A ferroelectric layer 19b is formed on the P-type substrate 3. A USG layer 18 is formed on the tungsten plug 13. An upper titanium (Ti) layer 15 and an upper titanium nitride (TiN) layer 17 are formed to cover the tungsten plug 13. The upper titanium (Ti) layer 15 and the upper titanium nitride (TiN) layer 17 are made of barrier metals. In this way, the ferroelectric material does not deteriorate, and even if a metallic electrode is placed on the contact region, ohmic resistance between them is prevented from increasing. <IMAGE>