Combinatorial investigation of ZrO2-based dielectric materials for DRAM capacitors

We investigated ZrO2-based new dielectric materials for random access memory by pulsed laser deposition (combi-PLD). We found that substitution of yttrium (Y) to ZrO2 system suppressed the leakage current effectively. MIM capacitor property of the promising composition candidates found in this system showed leakage current density less than 5×10-7 A/cm2 and the dielectric constant was 20. In addition, substitution of titanium (Ti) and tantalum (Ta) caused the dielectric constant up to ~ 22 within the allowed leakage level as well as 5×10-7 A/cm2. Zr-Y-Ti-O and Zr-Y-Ta-O system have a potential for high dielectric materials as a new material of DRAM capacitors instead of SiO2