A bottom electrode structure and manufacturing method is described for
producing crystallographically textured iridium electrodes for making
textured PZT capacitors that enables enhanced ferroelectric memory
performance. The use of seed layers originating from hexagonal crystal
structures with {0001} texture provides a smooth surface for growth of
{111} textured iridium, which exhibits the face-centered cubic ("FCC")
structure. This seeding technique results in {111} textured iridium with a
small surface roughness relative to the film thickness. The highly
textured iridium supports {111} textured PZT dielectric layer growth.
Textured PZT exhibits enhanced switched polarization, reduced operating
voltage and also improves the reliability of PZT capacitors used in
FRAM.RTM. memory and other microelectronic devices.
