Methods of forming metal layers using oxygen gas as a reaction source and methods of fabricating capacitors using such metal layers

A method of fabricating a capacitor comprising:

• forming an interlayer insulating layer on a semiconductor substrate;
• forming a contact plug that penetrates the interlayer insulating layer;
• forming a first metal layer on the contact plug by performing a first deposition process that includes at least one cycle of supplying a first metal source, and then purging, and then supplying an oxygen source, and then purging, and then plasma processing in a reduction gas ambient, and then purging;
• forming a second metal layer on the first metal layer by a second deposition process that includes multiple cycles of supplying a second metal source that consists of the same material as the first metal source, purging, supplying the oxygen source, and purging where at least some of the multiple cycles in the second deposition process do not include any plasma processing in a reduction gas ambient;
• removing portions of the first and second metal layers to form a lower electrode;
• forming a dielectric film on a surface of the lower electrode;
• forming an upper electrode on an upper surface of the dielectric film by forming a third metal layer on an upper surface of the dielectric film by a third deposition process that includes multiple cycles of supplying a third metal source, and then purging, and then supplying an oxygen source, and then purging where at least some of the multiple cycles in the third deposition process do not include any plasma processing in a reduction gas ambient, and then forming a fourth metal layer on an upper surface of the third metal layer by a fourth deposition process that includes at least one cycle of supplying the third metal source, and then purging, and then supplying the oxygen source, and then purging, and then plasma processing in a reduction gas ambient and then purging;
• and
• forming a metal interconnect in direct contact with the upper electrode.