A
ruthenium film deposition method is disclosed. In one embodiment of the method, a first
ruthenium film is deposited by using a PEALD process until a substrate is substantially entirely covered with the first
ruthenium film. Then, a second ruthenium film is deposited on the first ruthenium film by using a thermal ALD process having a higher deposition speed than that of the PEALD process. In the method, a ruthenium
metal film having a
high density is formed in a short time by combining a PEALD process of depositing a ruthenium film at a low deposition speed and a
deposition process of depositing a ruthenium film at a higher deposition speed. Accordingly, it is possible to form a ruthenium film having
high density, a
smooth surface, good adhesiveness, and a short
incubation period. Therefore, according to the embodiment, in comparison to cases of using only a PEALD process or an ALD process that has a long
incubation period, it is possible to obtain a ruthenium film having a large thickness and a
high density in the same time interval. As a result, the ruthenium film formed by the ruthenium film deposition method according to the embodiment is more suitable for
electrode structures of
semiconductor devices than the ruthenium films formed by using conventional methods.