A ferroelectric or high dielectric constant capacitor having a multilayer lower
electrode comprising at least two layersa platinum layer and a platinum-rhodium
layerfor use in a random access memory (RAM) cell. The platinum layer of
the lower electrode adjoins the capacitor dielectric, which is a ferroelectric
or high dielectric constant dielectric such as BST, PZT, SBT or tantalum pentoxide.
The platinum-rhodium layer serves as an oxidation barrier and may also act as an
adhesion layer for preventing separation of the lower electrode from the substrate,
thereby improving capacitor performance. The multilayer electrode may have titanium
and/or titanium nitride layers under the platinum-rhodium layer for certain applications.
The capacitor has an upper electrode which may be a conventional electrode or which
may have a multilayer structure similar to that of the lower electrode. Processes
for manufacturing the multilayer lower electrode and the capacitor are also disclosed.
