Ultrathin EOT high-κ/metal gate devices for future technologies: Challenges, achievements and perspectives (invited)

Ultrathin EOT-values are achieved by using optimized processing conditions and interface layer scavenging in metal-gated (TiN and TaN) HfO2 based planar and bulk-FinFET devices. EOT values down to 4.5 Å (Tinv∼8.5Å) in the planar devices and Tinv<11Å in bulk-FinFETs are demonstrated. Improved EOT-leakage current scaling is observed with the use of chemical oxides as compared to thermally grown SiO2 as interface layer for the HfO2. In contrast, the mobility is found independent of the compared interface layers, processing conditions and metal electrodes and follows one trend-line with EOT. The FinFET devices show decreased Tinv-values and improved mobility for more narrow fin widths.