Improved electrical and material characteristics of hafnium titanate multi-metal oxide n-MOSFETs with ultra-thin EOT (∼8 Å) gate dielectric application

A novel approach of fabricating laminated TiO₂/HfO₂ bi-layer multi-metal oxide dielectric was developed for high performance CMOS applications. Both layers showed negligible intermixing and no silicide formation. For the first time, ultra-thin EOT (∼8 Å) was achieved with increased effective permittivity (k ∼ 36) using the bi-layer dielectric. Leakage current characteristic was slightly higher than HfO₂ due to lower band offset of TiO₂. However, superior thermal stability (>950°C), significantly reduced hysteresis characteristic, and comparable interface state density represent the high quality of TiO₂/HfO₂ multi-metal oxide. Also, excellent subthreshold swing, increased transconductance, higher current drive, and -33% improved channel electron mobility compared to the control HfO₂ samples demonstrate the feasibility of new multi-metal oxide application for future CMOS technology.