DIRECT-CONTACT FERROELECTRIC CAPACITORS FOR MEMORY APPLICATIONS

The manufacturing of high-density ferroelectric memories or DRAM memor ies with high-dielectric constant materials in sub-micron IC processes demands for a technology where the capacitor is directly contacted fr om below to the access transistor. In this paper such a technology, ba sed on a sub-micron IC process with planarization and tungsten plugs, is described. The risk of deterioration of the CMOS circuitry (in part icular the oxidation of contacts) is successfully prevented by using a Ru/RuPt bottom electrode for the ferroelectric capacitors. With this electrode no increase of contact resistances nor degradation of CMOS c haracteristics are found after the ferroelectric processing, using a P bZrxT1-xO3 film deposited by organometallic chemical vapour deposition at 700 degrees C. The properties of direct-contact capacitors are goo d.