Higher-k Zirconium Doped Hafnium Oxide (HZO) Trigate Transistors with Higher DC and RF Performance and Improved Reliability

Equivalent oxide thickness (EOT) of gate stack has not scaled over past several technology nodes. For 3nm and beyond logic nodes it is imperative to resume EOT scaling to meet the high performance, low-gate leakage (I_Gate) and improved reliability requirements of advanced CMOS. In this work, we demonstrate a novel strategy to reduce the EOT of high-K HfO₂ gate-stacks, by enhancing the dielectric constant (κ) through optimum Zirconium (Zr) doping Hf: Zr ratio of 3:7. Through comprehensive theoretical modeling and experimental characterization, we show: 1) Higher-κ response in scaled Zr-doped (70%) HfO₂ (HZO) gate-stack, due to strong inter-domain electrostatic interactions; 2) a 22% EOT reduction in HZO FET over control HfO₂ without any mobility degradation, resulting in 20% and 18% boost in drive-current (ID,SAT) and transconductance (g_m) respectively; 3) improved device reliability such as positive bias temperature instability (PBTI) resulting in ~60mV higher V_MAX gain and 4) consistent enhancement in gm arising from thinner EOT that persists in the gigahertz frequency domain.