Hafnium Titanate bilayer structure multimetal dielectric nMOSCAPs

A novel approach of fabricating laminated TiO/sub 2//HfO/sub 2/ bilayer multimetal oxide dielectric has been developed for high-performance CMOS applications. Ultrathin equivalent oxide thickness (/spl sim/8 /spl Aring/) has been achieved with increased effective permittivity (k/spl sim/36). Hysteresis was significantly reduced using the bilayer dielectric. Top TiO/sub 2/ layer was found to induce effective negative charge from the flatband voltage shift. Leakage current characteristic was slightly higher than control HfO/sub 2/, and this is believed to be due to the lower band offset of TiO/sub 2/. However, the interface state density of this bilayer structure was found to be similar to that of HfO/sub 2/ MOSCAP because the bottom layer is HfO/sub 2/. These results demonstrate the feasibility of new multimetal dielectric application for future CMOS technology.