RUO2 TIN-BASED STORAGE ELECTRODES FOR (BA,SR)TIO3 DYNAMIC RANDOM-ACCESS MEMORY CAPACITORS/

Sputtered (Ba, Sr)TiO3 (BST) thin film capacitors have been fabricated with thick RuO2/TiN-based storage electrodes and poly-Si contact plug s, and the electrical properties of the storage electrodes have been s tudied, The electrode height was higher than 450 nm and the contact si ze was 0.8 x 0.8 mu m(2). Resistance of the storage electrodes includi ng contact plugs can be evaluated from the dispersion observed in capa citance-frequency measurements. TiN oxidation at the RuO2/TiN interfac e and native oxide at the TiN/Si contact contribute to the electrode r esistance of RuO2/TiN electrodes. With increasing BST deposition tempe rature, the thickness of oxidized TIN in RuO2/TiN electrodes increases and the electrode resistance increases correspondingly. A Bu layer in serted at the RuO2/TiN interface, a TiN/TiSi2/Si junction and rapid th ermal annealing in N-2 ambient of the TiN layer are eff effective ways to reduce the resistance of RuO2/TiN-based electrodes.