RU ELECTRODE DEPOSITED BY SPUTTERING IN AR O-2 MIXTURE AMBIENT/

Ru films are fabricated by de magnetron sputtering in an Ar/O-2 ambien t, as the bottom electrodes of Ba0.5Sr0.5TiO3 thin film capacitors. Th e Ru films deposited on Si in an Ar/O-2 mixture ambient show low resis tivity and low film stress and do not form Ru2Si3 following thermal pr ocessing even at 700 degrees C. It becomes clear that there exist very thin amorphous and crystalline layers composed of Ru, Si and O betwee n the Ru films and Si in the case of Ru films deposited in an Ar/O-2 a mbient. A low contact resistance at the Ru/n(+)-Si interface is obtain ed after annealing at 700 degrees C. An effective SiO2 film thickness of 0.42 nm is obtained for an actual Ba0.5Sr0.5TiO3 film thickness of 42 nm with a leakage current of less than I x 10(-8) A/cm(2) in the ra nge between -1.5 V and +1.8 V for a Ru/Ba0.5Sr0.5TiO3/Ru/n(+)-Si capac itor without a barrier metal layer.