HfO2 films and ZrO2 films are currently being developed for use as 
capacitor dielectric films in 85 nm technology node 
DRAM. However, these films will be difficult to use in 65 nm technology node or later 
DRAM, since they have a relative 
dielectric constant of only 20-25. The 
dielectric constant of such films may be increased by stabilizing their cubic phase. However, this results in an increase in the leakage current along the 
crystal grain boundaries, which makes it difficult to use these films as 
capacitor dielectric films. To overcome this problem, the present invention dopes a base material of HfO2 or ZrO2 with an 
oxide of an element having a large 
ion radius, such as Y or La, to increase the 
oxygen coordination number of the base material and thereby increase its relative dielectric constant to 30 or higher even when the base material is in its amorphous state. Thus, the present invention provides dielectric films that can be used to form 
DRAM capacitors that meet the 65 nm technology node or later.