Composite iridium barrier structure with oxidized refractory metal companion barrier and method for its fabrication

摘要

An Ir-M-O composite film has been provided that is useful in forming an electrode of a ferroelectric capacitor, where M includes a variety of refractory metals. The Ir combination film effectively prevents oxygen diffusion, and is resistant to high temperature annealing in oxygen environments. When used with an underlying barrier layer made from oxidizing the same variety of M transition metals, the resulting conductive barrier also suppresses the diffusion of Ir into any underlying Si substrates. As a result, Ir silicide products are not formed, which degrade the electrode interface characteristics. The Ir combination film remains conductive, not peeling or forming hillocks, during high temperature annealing processes, even in oxygen. The Ir-M-O conductive electrode/barrier structures are useful in nonvolatile MFMIS (metal/ferro/metal/insulator/silicon) memory devices, DRAMs, capacitors, pyroelectric infrared sensors, optical displays and piezoelectric transducers. A method for forming an Ir-M-O composite film barrier layer with an oxidized refractory metal barrier layer is also provided.