Semiconductor Device

A semiconductor device comprising:

• a transistor including first and second impurity regions;
• a bit line electrically connected to the first impurity region;
• a lower electrode electrically connected to the second impurity region;
• a dielectric layer on the lower metal layer and containing a first metal;
• a sacrificial layer on the dielectric layer and containing a second metal, wherein electronegativity of the second metal is greater than that of the first metal;
• and
• an upper metal layer formed on the sacrificial layer.

A semiconductor device comprising:

• a lower metal layer;
• a dielectric layer on the lower metal layer and containing a first metal;
• a diffusion barrier on the dielectric layer and containing ruthenium (Ru) or molybdenum (Mo);
• and
• an upper metal layer on the diffusion layer;
• wherein the diffusion barrier is configured to obstruct diffusion of oxygen atoms from the dielectric layer into the upper metal layer and to supply oxygen atoms to the upper metal layer.