Semiconductor devices and method of manufacturing the same

A method of manufacturing a semiconductor device, the method comprising:

• forming a mold layer having an opening on a substrate;
• forming a preliminary lower electrode layer on the mold layer, the preliminary lower electrode layer covering an inner wall of the opening of the mold layer and comprising a niobium oxide;
• converting at least a portion of the preliminary lower electrode layer to a first lower electrode layer comprising a niobium nitride by performing a nitridation process on the preliminary lower electrode layer;
• forming a dielectric layer on the first lower electrode layer;
• and
• forming an upper electrode layer on the dielectric layer.

A method of manufacturing a semiconductor device, the method comprising:

• forming a preliminary lower electrode layer on a substrate, the preliminary lower electrode layer comprising a niobium oxide;
• converting at least a portion of the preliminary lower electrode layer to a first lower electrode layer comprising a niobium nitride by performing a plasma nitridation process on the preliminary lower electrode layer;
• forming a dielectric layer on the first lower electrode layer, the dielectric layer comprising a hafnium oxide;
• and
• forming an upper electrode on the dielectric layer.