A method for fabricating a capacitor of a semiconductor device is
disclosed, which can control the composition of a dielectric layer easily
and improve the property of leakage current while not dropping the
throughput because it does not need to require to lower the process
temperature and pressure. The method includes: a) forming a bottom
electrode; b) forming an STO seed layer as a first dielectric layer on the
bottom electrode; c) forming a BST layer as a second dielectric layer on
the STO seed layer; and d) forming a top electrode on the BST layer.
