TiO2-based metal-insulator-metal structures for future DRAM storage capacitors

Capacitors with TiO2 and Al-doped TiO2 dielectric films grown by atomic layer deposition exhibit promising properties for application in DRAM technology for 20 nm node and beyond. For stabilization of the high dielectric constant rutile TiO2 phase RuO2 thin films were employed as a bottom electrode. The capacitors with the equivalent oxide thickness below 0.5 nm show leakage current below 10-7 A/cm2 at voltage 0.8 and 0.6 V, respectively. Current distribution study using Conductive AFM studies revealed preferential leakage current flow through grains. Low equivalent oxide thickness and low leakage currents of TiO2-based capacitors confirm that they can be considered as an alternative to the SrTiO3 DRAM capacitors.