Physical and electrical characteristics of high-κ gate dielectric Hf(1−x)LaxOy

Abstract The physical and electrical characteristics of high- κ gate dielectric Hf (1− x ) La x O y were systematically investigated in this work. Cross-sectional transmission electron microscopy and X-ray diffraction confirmed that HfO 2 film crystallized after annealing at 900 °C for 30 s. On the other hand, Hf (1− x ) La x O y films with x  = 0.15 (15% La) and x  = 0.5 (50% La) remained amorphous even after annealing at 900 °C for 30 s. Moreover, NMOSFETs fabricated with Hf (1− x ) La x O y films exhibit superior electrical performances in terms of drive current, electron mobility, charge trapping induced threshold voltage instability and gate leakage current compared to NMOSFETs fabricated with HfO 2 films. We also report for the first time the effective workfunction tuning of TaN (or HfN) metal gate with the incorporation of La to meet the workfunction requirements of NMOSFETs. These unique and advantageous characteristics of Hf (1− x ) La x O y make it a promising high- κ gate dielectric to replace SiO 2 and SiON to meet the international technology roadmap for semiconductors (ITRS) requirements for high- κ dielectrics.