Semiconductor device and method for fabricating the same

A method for fabricating a capacitor, the method comprising:

• forming a first ruthenium oxide layer over a substrate;
• forming a lower electrode ruthenium layer for a lower electrode on the first ruthenium oxide layer;
• forming a dielectric layer over the lower electrode ruthenium layer;
• and
• forming an upper electrode conduction layer for an upper electrode over the dielectric layer,
• wherein forming the first ruthenium oxide layer and forming the lower electrode ruthenium layer are performed by atomic layer deposition (ALD),
• wherein each of forming the first ruthenium oxide layer and forming the lower electrode ruthenium layer comprises:
• injecting a ruthenium source into a reaction chamber at a flow rate of approximately 50 sccm to approximately 500 sccm for approximately 0.1 sec to approximately 10 sec;
• purging the reaction chamber;
• injecting a reaction gas including O2 gas or O3 gas into the reaction chamber at a flow rate of approximately 200 sccm to approximately 1,000 sccm for approximately 1 sec to approximately 10 sec;
• and
• purging the reaction chamber,
• wherein a cycle of the injecting of the ruthenium source, the purging of the reaction chamber, the injecting of the reaction gas, and the purging of the reaction chamber is repeated one or more times,
• wherein forming the lower electrode ruthenium layer comprises chemically reducing the first ruthenium oxide layer to a ruthenium layer, and
• wherein at least one of an injection flow rate or an injection time of the reaction gas for forming the first ruthenium oxide layer is greater than an injection flow rate or an injection time, respectively, of the reaction gas for forming the lower electrode ruthenium layer.